In many infections some patients recover while others die or are permanently disabled. These extremes in clinical outcome may be determined as much by the capacity of the host to eliminate the infecting agent as by the antigenic load on the individual. Children with measles who do not recover may succumb to acute complications (mainly respiratory) or chronic disease (respiratory and neurological) may develop. Analysis of immunological function antedating any of these final events would assist in understanding their pathogenesis and possibly aid in management. In order to achieve t h i s , immunological responsiveness was at f i r st studied in 24 children with acute measles and compared with that in 20 children with established chronic post measles chest disease investigated 6 - 1 6 weeks after appearance of the rash. The immunosuppressive effects of acute measles were extensive. Total white cells were reduced and this reduction was accounted for entirely by lymphopenia which was equally expressed among the major lymphocyte sub-populations studied; the function of T cells, assessed by radioisotope incorporation into phytohaemaggiutinin-transformed lymphocytes and by delayed skin hypersensitivity to dinitrochlorobenzene, was depressed. Serum IgA was reduced in acute measles patients. In contrast there was a relative sparing of the measured indices of immunity in patients with chronic post measles chest disease, with the major defect being an impaired delayed hypersensitivity reaction to dinitrochlorobenzene. There were minor alterations in complement components in both groups of patients with the evidence suggesting minimal utilisation of the alternative pathway in acute measles and classical pathway in chronic patients. High levels of heterophile antibodies to sheep red blood cells were detected in patients with chronic chest disease. (11) The results suggested that the conditions for chronicity of pulmonary disease in measles were unlikely to be determined by persistent abnormalities in the immunopathological factors enumerated, most of which were normal in chronic patients. It was not possible to interpret the findings of defective delayed hypersensitivity and complement components in patients with chronic chest disease as being either the cause or the effect of chronicity. The latter findings would have to be compared with results in children who had recovered from measles studied six weeks after onset of rash. An attempt was made to resolve this problem. Twenty-two children with measles were studied in the acute stage of the rash and six weeks later and results compared with matched controls. The above findings in acute measles were confirmed: the total lymphocyte count and major lymphocyte sub-populations were significantly below control values. At six weeks the B cell and Null cell counts were s t i ll significantly diminished. The function of T cells assessed by radioisotope uptake by phytohaemagglutinin-stimulated lymphocytes and by delayed skin hypersensitivity reaction to dinitrochlorobenzene was impaired during the acute stage and this persisted for six weeks. No important abnormalities were detected in serum immunoglobulins and complement components. Partial reversal of immunological suppression caused by measles was therefore demonstrated at 6 weeks after the appearance of rash. Demonstration of a persistently defective delayed hypersensitivity in those who recovered made i t unlikely that this anergy was important in the development of chronicity. Complement abnormalities were similarly unrelated to progression to chronic lung damage. ( Children who recovered, when studied at six weeks, appeared to be worse o f f immunologically than those with established chronic chest disease following measles. Children with chronic chest disease were studied 6 - 1 6 weeks after onset of rash, by which time the partial reversal of immune deficiency, noted at 6 weeks, would be complete. Among the group of children studied during the acute rash of measles there were five who subsequently died and one who progressed to chronic chest disease. Results in these six children were compared with those in six age-matched children who recovered from measles within a week. In the children who subsequently died or developed chronic pneumonia, immunosuppression was more pronounced during the acute rash ( i . e ., 3 - 2 0 days before death) than in the children who recovered. The absolute total lymphocyte count (T and B cells) was s i g n i f i c a n t ly lower in those who died or developed chronicity. Mean serum C, was also lower in this group. There were no significant differences between the two groups for total white c e l l s , neutrophils, Null c e l l s, cells with both T and B cell markers, other complement factors, serum immunoglobulins and phytohaemagglutinin stimulation of lymphocytes. The total lymphocyte count in a further nineteen patients with measles who had died, studied retrospectively, was s i g n i f i c a n t l y lower than that in twenty-seven patients with measles who recovered. Children whose outcome was poor generally had absolute lymphocyte 3 counts below 2000 cells/mm whereas those who recovered had values above this level. (iv) Therefore children who w i l l die or develop chronic chest disease can be often distinguished, within two days of the appearance of the rash, from those who w i l l recover. In order to test the v a l i d i t y of this conclusion based on results obtained from a small sample the study was extended so as to increase the number of patients with measles who had severe lymphopenia (< 2000 cells/mm3). Seventy seven per cent of 30 children who had severe lymphopenia within 2 days of appearance of rash f a i l e d to recover: 30% died from pulmonary complications within a few days to two months of the onset of the exanthem while 47% developed chronic lung damage. This was s i g n i f i c a n t ly worse than the outcome in 30 children with lymphocyte counts above 2000 3 cells/mm , of whom 67% recovered, 33% developed chronic chest disease and none died. Persistence of severe lymphopenia (which was due to reduction 3 in both T and B cells) in those with i n i t i a l counts below 2000 cells/mm , for at least fifteen days after onset of rash, remained a good predictive index of morbidity and mortality. Reversal of immunoparesis in those with i n i t i a l severe lymphopenia was slower and less complete 42 days from the appearance of the rash in children who subsequently died or progressed to chronicity than in those who recovered. All patients who died f a i l ed to produce an adequate or sustained antibody response to measles. The results of these studies suggest that long term pulmonary and possibly neurological sequelae of measles are probably due to a transient widespread immunoparesis during early measles with persistent defects in specific immunity to measles and probably other viruses, whereas recovery is due to less severe effects of shorter duration. (v) In order to answer the question why some children do badly and others well after measles, studies on the HLA frequencies and measles antigen load have been undertaken in children with severe lymphopenia. Results of viral load are inconclusive and those of HLA suggest a trend towards histocompatibility linked genetic susceptibility to the development of severe lymphopenia in measles associated with HLA AW32. The therapeutic implication of these studies is that children with measles who are at risk for death and chronic disease can be identified early in the disease and intervention at this stage may reverse the severe immunosuppression which leads to rapid demise or modify the immunopathological changes progressing relentlessly in some cases to permanent lung and brain damage and occasionally to death. / Thesis (MD)-University of Natal, Durban, 1977.

Thesis (MD)-University of Natal, Durban, 1967.

The ocular complications of vitamin A deficiency have been known for many years, however, recent studies have suggested that marginal vitamin A status enlarges the risk of common childhood infections and increases mortality. It is therefore important to assess the vitamin A status, and some of its consequences, in children who are most likely to be at risk for vitamin A deficiency as this has important implications for promoting the health of children and for formulating appropriate primary health care policies. In South Africa very little data is available on vitamin A nutrition of communities; therefore one of the objectives of this research programme was to document the vitamin A status of African children who, because of historical inequities, are most likely to be at risk for deficiency. Sound, epidemiologically based surveys of vitamin A intake and body levels were conducted in a typical established township (using dietary intake as the measuring tool) and in a typical peri-urban informal settlement (using serum retinol and conjunctival impression cytology as the measuring tools). These studies revealed that the majority (97%) of children living in the established township surveyed had an adequate intake of vitamin A, whereas 44% of the children in the informal settlement had low serum retinol levels (20 ug/dL), and 18% had insufficient vitamin A, as assessed by 2 abnormal disc specimens, using the conjunctival impression cytology test. In order to investigate the interrelationsnips between vitamin A, other micronutrients and some risk factors, an analysis was undertaken of anthropometry, parasite infestation and blood concentrations of vitamin E, calcium, magnesium, phosphorous, albumin, haemaglobin, serum iron and ferritin and percent transferrin saturation. Significant positive correlations were found between serum retinol and all the biochemical indicators of iron metabolism studied except for serum ferritin. Ninety one percent of the children sampled were infested with parasites. These results highlight the fact that in this population close interconnections exist among nutrients and suggest that attempts at correcting vitamin A deficiency in such communities should be based on comprehensive intervention programmes rather than on single nutrient replacement. The impact of infections on blood levels of vitamin A was investigated in African children with severe measles. In addition, substances related to vitamin A metabolism such as other micronutrients (zinc, vitamin E) and proteins (retinol binding protein, prealbumin, albumin) were measured in serum. In addition the changes induced in these substances by vitamin A supplementation (offered in a randomised, double blind, placebo controlled trial) were studied. Serum retinol as well as the other nutrients measured were significantly reduced early in the exanthem in measles patients as compared to healthy controls. Vitamin A and prealbumin levels on day 8 (of the intervention trial) were significantly increased in the supplemented group compared to the placebo group. vitamin A levels in serum correlated with those of retinol binding protein (RBP), prealbumin and zinc. These findings strengthen the hypothesis that hyporetinaemia during measles is the consequence of impaired mobilisation of retinol stores from the liver. The effect of reversing the temporary lowering of serum retinol concentrations during acute measles infections by supplementation with vitamin A was investigated in a hospital based, randomized, double-blind, placebo controlled trial. The two groups were comparable in known covariates of measles severity : weight/age centiles; overcrowding; rash; total 90% of the patients had blood lymphocytes; serum levels pre-albumin, RBP, vitamins A and E. of zinc, albumin, hyporetinaemia. Integrated Morbidity Scores ( IMS) derived from diarrhoea, herpes and respiratory tract infection (radiologically confirmed) were assigned on day 8, at 6 weeks and 6 months - these were reduced by 82%, 61% and 85% respectively in the supplemented group. This was mainly due to reduced respiratory tract infection. There was one death in the placebo group. At 6 weeks there was significant weight gain in the supplemented group. Despite the selected sample, attention to multiple covariates enhances the validity of the data obtained and supports the current WHO recommendations for vitamin A supplementation during measles. There are several mechanisms by which vitamin A is thought to have its effect of reducing morbidity, one of which is by improving immune responsiveness. This particular mechanism has not been adequately studied in children; most of the studies having been conducted in animals. The effect of vitamin A supplementation on selected factors of immunity in African children with complicated measles was therefore investigated during the randomized double-blind, placebo controlled, intervention trial described above. Placebo and treated groups had similar baseline characteristics. In the treated group there was a significant increase in total number of lymphocytes (day 42, P = .05) and measles IgG antibody concentrations (day 8, p = .02), both of which have consistently been shown to correlate more closely with outcome in measles than other immunological, clinical and radiological factors. Interleukin-2 (IL-2) and plasma complement (C3 ) values were unaffected by vitamin A supplement.at.Lon , These findings reinforce results from animal studies which show that the pathways of vitamin A activity in decreasing morbidity and mortality are partly founded on selective immunopotentiation. In conclusion epidemiological and biochemical methods which were used to assess the vitamin A status of African children in South Africa revealed that overt vitamin A deficiency is not a Public health issue to the extent it is in the poor rice eating nations of the world. Marginal vitamin A deficiency is however prevalent in informal settlements. Interventions to reverse this marginal vitamin A deficiency should be incorporated in comprehensive programmes to ensure food security. Infections such as measles which increase utilisation and inhibit mobilisation from body stores are damaging to vitamin A homeostasis in the individual. The morbidity associated with measles can be reversed by high dose vitamin A supplementation during the acute phase of the infection. Improving immune responsiveness is one of the likely paths of vitamin A activity in decreasing morbidity from measles. / Thesis (Ph.D.)-University of Natal, Durban, 1993.

Background: HIV-1 envelope (Env) diversity is arguably the most significant challenge for the development of an efficacious vaccine. An ideal vaccine would elicit the production of broadly neutralizing antibodies (nAb), capable of retaining potent activity against a diverse panel of viral isolates. The evolutionary forces that shape the diversity of envelope and ensuing nAb responses are incompletely understood in HIV-1 subtype C infection, the dominant subtype globally. Therefore there is an urgent need to define the patterns of envelope diversity, determine the correlates of immune protection and to discover subtype C immunogens in order to develop a globally relevant vaccine. Methods: We applied the single genome sequencing strategy to study plasma derived viruses from four slow progressors and four progressors over a median of 21 months between study entry and study exit. The participants‘ samples were from the Sinikithemba cohort of antiretroviral therapy-naïve chronically infected individuals and were termed slow progressors or progressors based on CD4 T-cell counts and viral loads over two years. We analyzed env sequence diversity, divergence patterns and envelope characteristics across the entire HIV-1 subtype C gp160. We studied the evolution of autologous nAb (AnAb) and heterologous nAb responses in order to test the hypothesis that slow disease progression is associated with more potent autologous or heterologous nAb responses. Furthermore, genotypic env characteristics were correlated to potency of neutralization in order to understand possible differences in nAb responses with divergent rates of disease progression and to describe genotypic differences associated with differential nAb potencies. In addition, the binding affinities of HIV-specific immunoglobulins (IgGs) and the affinities of the IgGs to various Fcγ receptors (both activating- FcγRI, FcγRIIa, FcγRIIIa; inhibitory- FcγRIIb) were assessed. These binding affinities were used as a surrogate for the recruitment of effector functions of cells of the innate immune system e.g. macrophages or natural killer cells to initiate antibody-dependent cell-mediated cytotoxicity (ADCC) or antibody dependent cell-mediated viral inhibition (ADCVI) and these were correlated to markers of disease progression namely CD4 T-cell counts and viral loads. Results: Intra-patient diversity was higher in slow progressors for regions C2 (p=0.0006), V3 (p=0.01) and C3 (p=0.005) compared to progressors. Consistent with this finding, slow progressors also had significantly increased amino acid length in V1-V4 with fewer potential N-linked glycosylation sites (PNGs) compared to progressors (p=0.009 and p=0.02 respectively). Similarly, in progressors, the gp41 region was significantly longer and had significantly fewer PNGs compared to slow progressors (p=0.02 for both parameters). Positive selection was prominent in regions V1, C3, V4, C4 and gp41 in slow progressors, whereas in progressors, it was prominent in gp41. Signature consensus sequence differences between the groups occurred mainly in gp41. Neutralizing antibodies (nAb) evolved over time in progressors, as evidenced by significantly higher nAb IC50 titers to baseline (study entry) viruses when tested against study exit time-point plasma compared to contemporaneous responses (p=0.003). In contrast, slow progressors‘ nAb titers did not differ significantly between study entry and study exit time points. nAb IC50 titers significantly correlated with amino acid lengths for C3-V5 (p=0.03) and V1-V5 (p=0.04) for slow progressors and V1-V2 for progressors (p=0.04). Slow progressors and progressors displayed preferential heterologous activity against the subtype C panel. There were no significant differences in breadth of responses between the groups for either subtype A or C. Neutralization breadth and titers to subtype B reference strains however, was significantly higher in progressors compared to slow progressors (both p<0.03) with increasing nAb breadth from study entry to study exit in progressors. Progressors had cross-reactive neutralizing antibodies that targeted V2 and V3. Binding affinities of non-neutralizing antibodies to HIV-specific gp120, gp41 and p24 and to activating and inhibitory Fcγ receptors (FcγRs) were similar in both groups. However, in slow progressors, CD4 T-cell counts correlated inversely with antibody binding affinity for the activating FcγRIIa (p=0.005). Conclusions: These data suggest that separate regions of Env are under differential selective forces, and the heterogeneity of env diversity and evolution differ with HIV-1 disease course. Single genome sequence analysis of circulating viruses in slow progressors and progressors indicate that diversity, length polymorphisms, sites under positive selection pressure, and PNGs consistently map to specific regions in Env. Cross-reactive neutralizing antibodies targeting epitopes in V2 and V3 indicate that nAb breadth may be dictated by a limited number of target Env epitopes. Certain key N-linked glycosylation sites were shown to be crucial for antibody neutralization. The potencies of autologous nAbs were directly affected by the amino acid lengths in certain regions of Env gp160 and by the numbers of PNGs. Target vaccine immunogens may have to be given over long periods of time and may have to include multiple subtype immunogens to elicit the production of potent, broad cross neutralizing antibodies with high binding affinity. Overall, the data suggest that neither nAbs nor non-neutralizing antibodies could be directly associated with disease attenuation in this cohort of chronically infected individuals. However, continuous evolution of nAbs was a potential marker of HIV-1 disease progression. Further studies on larger cohorts to identify people with potent nAbs and to identify specific targets of these antibodies are needed. Furthermore studies of non-neutralizing antibodies in HIV-1 infection using functional assays will be required in order to determine their role in HIV-1 pathogenesis. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

Background: Breastfeeding is known to have benefits both for maternal and child health. Some questions around the benefits and risks of breastfeeding in the presence of HIV infection still remain unclear. Aims: To study the effects of infant feeding mode by HIV-positive mothers, on maternal and child health. In addition, to assess the effect of nutritional supplementation to HIV-positive lactating mothers on nutritional and health status of mothers and their infants and on the quality of breastmilk. Methods: The study had 2 components; a prospective study to examine the impact of infant feeding mode on nutritional and health indices in mothers and their infants and within it a nested randomized controlled clinical trial to study the impact of a daily 50 g soya/peanut based supplement during breastfeeding on the above parameters. The measurements included anthropometry; body composition indicators (using both deuterium dilution and BIA); haematology and biochemical markers; as well as incidence rates of opportunistic infections and clinical disease progression. Breastmilk was analysed for both macro and micronutrients. Cervical screening was offered to all the women. Results: AFASS criteria were fulfilled by 38.7% of the formula feeding mothers. No significant differences between the formula feeding and breastfeeding groups in terms of haematological, immunological and body composition changes were seen. Breastfeeding mothers had significantly lower events with high depression scores (p=0.043). Longer duration of breastfeeding was observed to be significantly associated with a mean increase in CD4 count (74 cells/μL) and better health outcomes. The supplement made no significant impact on any maternal or child outcomes except for a limited effect on mothers with low BMI, where it was significantly associated with preventing loss of lean body mass (p=0.026). Breastfeeding infants had a significantly lower risk of diarrhoea and hospitalisation at 3 months (p=0.006 and 0.014 respectively). Both breastfeeding and longer duration of breastfeeding was significantly associated with better development scores and growth parameters. Supplementation made no impact on breastmilk composition. Of the 86 mothers who agreed for cervical screening, 27.6% had human papilloma virus infection. Conclusions: Breastfeeding is not harmful to the mother despite the presence of HIV infection. On the contrary we observed both breastfeeding and longer breastfeeding duration to be associated with better maternal and child outcomes. Mothers are still choosing formula feeding inappropriately presumably because of the availability of free formula and/or sub-optimal counseling. The new (2010) local PMTCT guidelines based on WHO recommendations should reverse this. Food insecurity was prevalent amongst 32% of our study population, highlighting the need to include sustainable and empowering solutions to encounter this problem. Less sustainable solutions such as nutritional supplementation should be targeted to the malnourished and in emergency situations. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

There are comprehensive accounts of the nephrotic syndrome in childhood in temperate countries. Many of the important features of this disease have been known for close on to two decades. The causal link between malaria and nephrosis in tropical Africa has also been recognised and documented for a similar length of time. Very little was known of the nephrotic syndrome in the sub-tropical zones of Africa where malaria is not endemic. Anecdotal evidence in South Africa suggested that African children with this disease appeared to have steroid resistant nephrosis and a more protracted clinical course than expected from prevailing accounts in the literature and that Indian South African children generally responded to steroids. This thesis is the result of detailed investigations in to this disease in African and Indian children in Durban, South Africa. 2. Preliminary Study A preliminary study was undertaken in which 53 (12 African and 41 Indian) children with the nephrotic syndrome defined by clinical and biochemical criteria 1 ii were studied. Renal biopsies were not available on these patients. The results revealed that two thirds of the African children were over 5 years of age and 50% were males. Of the Indian children 50% were under 5 years of age and 50% were males. Nine African children were treated with steroids and 8 did not respond whereas 31 of the 39 Indian children treated clearly responded to steroid therapy. In addition 5 Indian patients were treated with cyclophosphamide and 3 responded. On follow-up 7 of the African children had persistent proteinuria, 2 experienced remissions and 3 were lost to follow-up. All the Indian patients experienced remissions. The differences between the 2 groups of nephrotic patients were quite striking and therefore a more detailed prospective study of this problem was undertaken. 3. Prospective Study of Primary Nephrotic Syndrome One hundred and seventy children of whom 104 were African and 66 Indian with primary nephrotic syndrome were studied. In both racial groups the male sex dominated, Indian children tended to present iii at a younger age group whereas African children presented at two peak ages, 5 years and between 5 - 10 years. 3.1 Histological Differences The histological types found on light microscopic examination of renal tissue were distinctly different between the African and the Indian children. The majority (85.6%) of the African children had 'obvious' glomerular lesions, the commonest being extramembranous nephropathy (29.8%). Although the proliferative group was the single largest group (40%) none of the subgroups exceeded the extramembranous type in their number. Minimal change accounted for only 14.4% of the African children with nephrotic syndrome. The majority of Indian children (72.7%) had minimal change on light microscopy, 9.1% focal glomerulosclerosis and 12.1% had proliferative changes. 3.2 Immunofluorescence Immunofluorescent studies also indicated differences between the two groups of patients. Generally, heavier deposits of immunoglobulins iv and complement components were identified on renal biopsy specimens of African children. This occurred even in MCNS where most African children had heavy IgG, light IgM, IgA and complement components whereas only a few of the Indian children had light IgM deposits. Similar differences were observed in diffuse mesangial proliferative glomerulonephritis and focal glomerulosclerosis where the numbers of patients were comparable. 3.3 Presenting Features Clinical features at presentation in the two groups were different, as expected from the nature of the histological findings in each group. In the African children (all histological groups) haematuria occurred in 35.5%, hypertension 16.3% and renal failure in 2.9%. The clinical features in the Indian children were not too different from MCNS elsewhere. Haematuria occurred in a small percentage (3%) of MCNS but was more frequent (10.7%) in other groups. Hypertension and renal failure occurred infrequently in histological categories other than MCNS where they did not occur at all. 3.4 Course and Outcome In view of the above it was not unexpected to find that the clinical course and outcome in the two groups were quite dissimilar. African patients in certain of the histological groups fared reasonably well, but none of the groups had the excellent prognosis of Indian MCNS. 3.4.1 Minimal Change One third of the African MCNS patients remitted and this was unrelated to steroids. The remainder who were followed for a reasonable duration of time remained proteinuric. None developed signs of serious renal impairment (azotaemia, hypertension). Indian MCNS experienced an excellent prognosis with 97.8% achieving remission and 81.6% being steroid sensitive. One third of these patients had a single episode of nephrosis while frequent relapses occurred in 28.2%. 3.4.2 Extramembranous Nephropathy Patients with extramembranous nephropathy, the largest group in the African patients, experienced hypertension more often (20%) vi and remission less often (30%) than do children in temperate climates. The clinical presentation, course and outcome in the majority of these patients were similar to adults with extramembranous nephropathy. 3.4.3 Proliferative Glomerulonephritis The patients in the proliferative group had a variable outcome depending on the subgroup to which they belonged. In diffuse mesangial proliferation, African patients had a higher incidence of hypertension and fewer remissions and fared less well than Indian patients. The diffuse endocapillary glomerulonephritis, membranoproliferative and focal proliferative nephritis groups of patients suffered severe disease with a failure to remit and progression to death. In the diffuse exudative group, remissions occurred or proteinuria persisted but severe relapse and death did not occur. The worst prognosis was in the focal proliferative group with the highest incidence of persistent relapse. 3.4.4 Focal Glomerular Sclerosis Focal glomerular sclerosis was an unusual vii histological diagnosis in the African child (3.9%) with a poorer prognosis (persistent proteinuria or death) when compared to Indian children in whom one third remitted and the rest had persistent proteinuria. 3.4.5 Tropical Nephropathies It is difficult to comment on the course of the tropical nephropathy (not related to malaria) and tropical extramembranous groups as the numbers are small. However, in tropical extramembranous, none remitted (all African children) and in tropical nephropathy one Indian child remitted but one of 2 African children died and the other had persistent proteinuria. 3.5 Response to Therapy Perhaps the most important practical aspect of the nephrotic syndrome in the African child was the response to steroid therapy. Thirty two African children were given steroid therapy. Thirty (93.7%) did not respond. Five children deteriorated or died during steroid therapy. Very few patients (4) were given cyclophosphamide and none responded. viii Generally intravenous albumen, diuretics and a high protein diet were not very effective in those patients with severe, clinical disease but were of benefit in milder disease. Indian children taken as a whole, responded well to steroid therapy. Seventy-eight percent of the whole group responded to steroids and 21.4% developed cushingoid features. Of the 19 Indian children (all MCNS) treated with cyclophosphamide 63.2% responded of whom about a quarter got toxic side effects (alopecia, darkened nails and leucopenia). Chlorambucil therapy in 4 children (all MCNS) was successful in all. 3.6 Complications Serious infections (septicaemia, peritonitis, urinary tract infection, meningitis, arthritis, osteitis, measles, chicken pox) occurred in 8.7% of the African patients. Eighteen percent had less severe infections. Just over a quarter of the Indian children suffered severe infections. The majority of these patients were MCNS and about 50% were on steroids or cyclophosphamide at the ix time of their infection. Renal biopsy complications were minor, these being abdominal pain and tenderness or transient haematuria. A few patients developed renal haematomas which were detected or monitored by ultrasonography. The single serious complication was the development of a renal abscess at the biopsy site requiring partial nephrectomy. 3.7 Mortality The overall mortality was 5.8%. Seven of the 10 deaths were African children in the Proliferative Group and 3 of the 10 deaths were Indian children. 4. Secondary Nephrotic Syndrome The secondary nephrotics formed an interesting group of patients. Of the 22 patients classified as secondary nephrotics 11 (50%) were related to streptococcal infection either as rapidly progressive glomerulonephritis or transient NS following APSGN. HBsAg was detected in the blood of 8.6% of the African patients. However the HB sAg carrier rate in this age group is 7.4%.The incidence in these patients probably reflects the high incidence in this population group. Collagen vascular disease occurred in 2 patients, both Indian. 5. Conclusions and Recommendations The results of this study demonstrates the strikingly different incidences of the various histological categories in the two race groups studied with a less favourable prognosis and fewer remission rates being achieved in African children. Indian children had more serious infections more often than African children. Steroid and immunosuppressive agents were of no value and probably hazardous in the African child. Some patients deteriorated on these drugs. Indian children who had an excellent response to these drugs were however at significant risk of developing serious infections. Why African children in Durban develop obvious glomerular lesions has not been established. Known or possible aetiological agents such as malaria, schistosomiasis, streptococcal infections and collagen diseases have been excluded. The answer to the above question may in fact lie in genetic predisposition,host factors and environmental influences, either singly or in combination, predisposing to the development of obvious x i glomerular lesions. These require more intensive investigation and judging from the yield of similar studies in other areas of the world expectations have to be guarded. / Thesis (M.D.)-University of Natal, 1981.

This study was undertaken to investigate the relationship between Natural Killer cells and HLA-G at the placental barrier in HIV-I infected pregnant women and to establish the significance, if any, to in utero infection. Fifty-five HIV -I infected pregnant women were recruited into the study after consent was obtained. Blood samples were collected from both mothers and babies for viral loads and CD4+ cell counts. Placental samples were obtained from pregnancies at delivery and examined by immunoperoxidase immunohistochemistry methods using monoclonal antibodies to p24 antigens and Natural Killer (CD56+) cells. HLA-G expression was quantified using real-time polymerase chain reaction. Analysis of viral loads and CD4+ cell counts were undertaken in categories. No significant association was observed between the viral load of mothers and their CD4+ cell counts. Eighteen percent of the women in this study population had 5 log viral loads with a transmission rate of 0.27(95% Cl, 0.15 - O. 39). Maternal viraemia was significantly associated with transmission of infection to babies (p = 0.047). The odds ratio indicated that for every 1 log increase in maternal viral load the babies were 3.1 times more likely to acquire the infection (Exp (B) = 3.137 (95%CI, 1.015-9.696). Furthermore, the study found that a higher number of female babies were infected than males. Although not statistically significant the odds ratio indicated that female babies were 3.1 times more likely to become infected than males (Exp (B) = 3.110 (95%CI, 0.819-11.808). We report here the results of immunohistochemistry for p24 antigens and NK (CD56+) cells and compare them to the immunological responses of both mothers and babies at birth. HIV-1 antigens were detected in 94.5% of all placentas by immunohistochemistry. Infiltration of CD56+ was found in 98% of placental tissue. The analysis revealed that the presence of p24 antigens in placental tissue was not influenced by maternal viral load or CD4+ cell counts. Lower median NK cell values were observed in placentas of mothers with infected babies as compared with the uninfected cluster. Although not statistically significant, the risk of vertical transmission was increased 3.4 times more in placentas which had lower NK cell values. According to the odds ratio, babies CD4+ counts were affected by every 1 log increase in mother's viral load. Overall, maternal viral load emerged as a strong predictor for risk of infection from infected mothers to their infants. Our analysis indicated that female babies were 3.7 times more likely to acquire the infection than males. Using data obtained from real-time PCR we investigated the relationship between maternal viral load and the quantity of HLA-G expression (p = 0.045; 95%CI 1.029- 11.499). Logistic regression models revealed that mother's viral load was the strongest risk factor for vertical transmission. No statistically significant correlation was noted with HLA-G and viral transmission. However, the odds ratio indicated that the risk of infection increased by 1.3 with every 1 fold increase in HLA-G expression. An analysis of mother-to-child transmission rates by gender revealed that the odds ratio for transmission was 3.4 times more in female babies than in males. We then investigated the relationship between maternal viraemia and HLA-G expression. A positive correlation between maternal viral load and placental HLA-G was observed (p = 0.038). When gender susceptibility to HLA-G expression was explored a statistically significant association was observed in placental tissue of mothers with infected and uninfected male babies and HLA-G expression (p = 0.013). To conclude, the analysis found that HLA-G was up regulated 3.95 times more in placental tissue of mothers with infected babies than in mothers with uninfected babies. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2007.

Background: Prevention of Mother-to-child transmission (PMTCT) of human immunodeficiency virus (HIV) remains a significant challenge in resource-poor settings despite the advances in antiretroviral (ARV) treatment. HIV-1 infected individuals are able to achieve viral control naturally, however the underlying mechanisms of immunological control in children remains poorly understood. This study was conducted from 2006 to 2010 to investigate correlates of immune control in HIV-1 clade C infected mother-child pairs in the absence of ARVs. Genotypic and phenotypic viral characteristics, cellular immune responses to HIV-1 and host genetics were characterized and correlated with clinical markers of disease progression. Materials and Methods: To achieve the objectives of the study, three cohorts of mother-child pairs were investigated. The first cohort included 60 untreated mother-child pairs and a further ten uninfected children as controls. The second cohort comprised of ARV treated pairs (n=60). The third cohort consisted of 374 mothers and 374 children (infected, exposed uninfected, HIV negative). Plasma viral loads and absolute CD4+ T cell counts were routinely performed in all three cohorts. HIV-specific CD8+ T cell responses were analyzed by interferon gamma (IFN-γ) enzyme linked immunosorbent spot (ELISpot) assays. Viral replicative fitness was assessed using a green fluorescent protein reporter cell line (GFP).Multi-parameter flowcytometry allowed for the investigation of T cell regulation, exhaustion and activation using CD127/CD25, TIM-3/PD-1 and HLA-DR/CD38 markers respectively. IL-10 promoter single nucleotide polymorphisms (SNPs) at positions -592 and -1082 were determined by TaqMan allelic discrimination assays. Plasma IL-10 levels were measured using a luminex assay. Results: To describe the CTL responses elicited to various regions of the HIV proteome in HIV-infected treatment naïve children. Sixty children under one year of age in the untreated cohort were analyzed for CTL responses spanning the HIV genome, for which only 30 had detectable responses. There was no significant difference in viral load between respondersand non-responders (p=0.2799). The responders predominantly targeted Nef (49%), Gag (17%) and Env (14%) regions. Markers of T cell exhaustion and regulation and theirrelationship to markers of disease progression, were next investigated as these parameters may explain the inability of T cells to effectively control HIV infection. T cell phenotyping compared treated, untreated and uninfected subgroups. In infected children, CD8+ T cells were significantly higher for both the inhibitory marker TIM-3 (p=0.001) and exhaustion marker PD-1 (p=0.0001) compared to uninfected children. Median expression of TIM-3 was higher on CD8+ T cells (46%) compared to CD4+ T cells (20%). TIM-3 and PD-1 expression on T cells were maintained at high levels over time. The frequency of absolute Tregs (p=0.0225) were found to be significantly higher in untreated compared to treated children. HLA-DR+CD38+ on CD8+ T cells were significantly up-regulated in untreated children compared to treated (p=0.002) and uninfected children (p=0.0177). HLA-DR+CD38+ was also significantly higher in children less than 6 months compared to older children on CD4+ (p=0.0437) and CD8+ T cells (p=0.00276). Interestingly, we observed a significant negative correlation between magnitude of CTL response and CD25+CD127- (p=0.0202; r=-0.7333) as well as HLA-DR+CD38+ (p=0.0408; r=-0.5516) on CD8+ T cells. IL-10 is an important immunoregulatory cytokine that has been shown to affect the outcome of chronic viral infections. IL-10 polymorphisms have previously been associated with IL-10 levels and HIV-1 outcomes in adults. Polymorphisms associated with different levels of IL-10 production and their relationship with transmission, markers of disease progression and immune responses were next investigated in this mother-child HIV transmission setting. Genetic analysis of IL-10 in cohort three revealed that HIV-1 acquisition was not associated with either IL10 -592 (AA/CA vs CC) or IL10 -1082 (AA/AG vs GG) single nucleotide polymorphisms (SNPSs). There was a significant association between IL10 -1082 and HIV-1 transmission (p=0.0012). No correlation was observed between IL10 -592 (p=0.4279) or IL10 -1082 SNPs (p=0.6361) and mortality rates in children. IL10 -592C was associated with an elevated magnitude of IFN-γ CD8+ T cell response compared to IL10 -529A (p=0.0071). We found a significant positive correlation between IL-10 plasma levels and viral loads (p=0.0068; r=0.4759) and the ages of the children (p=0.0312; r=0.1737). Conclusion: CD8+ T cell responses and viral fitness did not explain differences in disease progression in selected HIV-1 untreated clade C transmission pairs. T cell activation and regulatory markers influence CTL immune responses resulting in poor clinical outcome. IL10 -1082 polymorphisms may be used as a predictor of HIV-1 transmission. The association between increased IL-10 plasma levels and high viral loads suggest that IL-10 contributes to immune dysfunction in paediatric HIV-1 infection. This study has extended our understanding of immunological and genetic correlates of mother-to-child transmission and disease outcome in ARV naïve (naturally controlling) and HIV treated infected children. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

Introduction. Previous studies have established that infants born to mothers with advanced HIV disease and co-infections are smaller, premature and have rapidly progressive HIV disease and an early death. King Edward VIIIth Hospital, in Durban, admits many sick mothers and manages a large proportion of low birth weight and ill newborns. On discharge and follow-up, the mortality and morbidity of these infants are known to be high and are related to the prematurity. How much is related to being HIV exposed is still uncertain. Aim. To determine the perinatal transmission rate of HIV-1 and mortality at 12 months in HIV exposed infants that were admitted to and discharged from the Neonatal Unit, in Durban, South Africa. Methods. In this observational study, data from the outpatient charts of HIV exposed infants that required specialised neonatal care and subsequent follow up, between the period November 2007 and December 2009, were collected. Perinatal transmission rates and mortality of these infants were compared with maternal and infant risk factors. Results. Data on 463 HIV exposed, predominantly low birth weight infants are presented. The median maternal CD4 count was 309cells/mm3 with 16.8% of mothers commenced on HAART. Maternal co-infection with TB was found in 19.2% of the cohort. Early HIV transmission occurred in 11.5% of infants and was influenced by the type of ARV exposure (None, 20%; single dose NVP, 14.3%; dual therapy, 10.6%; maternal HAART, 8.5%). The dual therapy regimen for 7 days was more protective than that for 28 days (p=0.045). HIV infection was associated with higher risk of neonatal sepsis (RR 1.6; 95% CI, 1.1-2.3; p=0.015). The mortality for the cohort at 12 months was 10%. Maternal HAART was associated with a lower mortality: 2.95% vs.10.2% (RR 3.0; 95% CI, 0.4-20.5). There was a higher mortality rate in those that were low birth weight (RR 4.2; 95% CI, 1.02-18.8; p=0.037); those that were HIV infected (RR 4.8; 95% CI, 1.9-11.6; p=0.002) and those that were breastfeeding compared to formula feeding (RR 2.7; 95% CI, 1.1-6.8; p=0.038). Discussion. Rates of HIV transmission within the PMTCT programme were similar to that reported by the Department of Health. Early maternal ARVs for PMTCT prophylaxis, prevents HIV transmission. The coverage of maternal HAART was sub-optimal. Breastfeeding was associated with a higher HIV transmission rate and was most likely associated with non-exclusive breastfeeding during neonatal admission. Recommendations. Maternal HAART or ARV prophylaxis should be commenced early in the pregnancy for the best benefits. Meticulous attention should be paid to the feeding practices of high risk HIV exposed infants admitted for specialised neonatal care. / Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2012.

Glomerulonephritis as an extra hepatic manifestation of chronic HBV infection has now been well documented [1,2,3,4,5]. HBV-associated nephropathy has been described in areas of both high and low endemicity [6]. In Africa HBV-associated nephropathy has been reported from the southern, central and northern regions [7,8,9,10,11]. In the southern African continent the prevalence of HBV-associated nephropathy appears to be higher than the rest of the continent [12]. In KwaZulu/Natal, South Africa, the prevalence of hepatitis B surface antigenaemia (HbsAg) in urban, rural and institutionalised children was reported to be 6.3%, 18.5% and 35.4% and the HBV exposure rates, as shown by the presence of any marker of HBV infection, 19.5%, 65.1% and 70.1% respectively amongst black children [13]. Prior experience of nephrotic syndrome (NS) and its association with HBV in black children, already published in a series of reports, showed HBV-associated nephropathy to be the commonest form of nephrotic syndrome among black patients in KwaZulu/Natal; membranous nephropathy (MN) being the commonest histological type reported [7,14]. The only other large series of HBV-associated nephropathy in southern Africa was from Cape Town of a large cohort of children, mainly of mixed ancestory (coloured), with a small number of black children [8]. There have been no other large studies of this condition amongst black children in Africa. We therefore undertook a series of studies to delineate the spectrum of this disease in black children with regard to the following: clinical presentation, laboratory findings, natural history, biosocial background, genetics (using HLA Class I and II antigens) as well as the impact of treatment and prevention by immunisation. We commenced these studies by reviewing our 20-year experience of 636 children with NS in Durban, South Africa for the period 1976- - 1995. Three hundred and six (48.2%) were blacks, 307 (48.2%) Indians and 23 (3.6%) were a mixed group (coloured); 91 (14.3%) could not be categorised and were excluded from the analysis. In black children, membranous nephropathy accounted for 43% of all cases of NS; 86.2% of these 306 children were associated with hepatitis B virus antigens [15]. This contrasts with the 2% - 5% prevalence of idiopathic membranous nephropathy reported in western countries [16]. We then proceeded to document the clinical features of this disease in black children. One hundred and thirty-three children with NS positive for HBV carriage were studied. In 70 patients the histological type was membranous; 46 of these 70 patients were followed up for a mean of 3.4 years (range 1-11). Spontaneous elimination of both HBsAg and HBeAg occurred in 10 (21.7%) of the 46 patients; 16 (34.8%) cleared HBeAg alone. Co-existing liver disease occurred in 18 (25.7%); hypocomplementaemia (low C3 and C4) in 22 (47.8%) and 5 (10.9%) of these 46 children respectively. Sixty-five (92.9%) of the 70 patients had normal renal function; 1(1.4%) impaired renal function; 3 (4.3%) chronic renal insufficiency and 1(1.4%) end stage renal disease at last hospital visit. Twelve (17.1%) of the 70 patients were in remission; all having cleared HBeAg. HBVMN was clinically indistinguishable from 24 children with idiopathic MN although biochemical characteristics were different. There were 23 patients with histological lesions other than MN. Forty patients with clinical, biochemical and serological findings similar to those with HBVMN and the other histological types, were unbiopsied. This report delineates the natural history of HBV infection in black South African children with NS, the majority of whom have MN. Disease remission in HBVMN parallels elimination of HBV antigens, particularly HBeAg. Comparison of HBVMN with idiopathic MN revealed clinically indistinguishable characteristics but unexplained biochemical differences [14]. Little is understood of the biosocial context in which HBV-associated nephropathy (particularly MN) develops. In the next two studies we evaluated HBV status and proteinuria in family members and household contacts of index children with HBVMN to test the hypothesis that HBV carriage and asymptomatic proteinuria are closely linked and may be causally associated. In the first of these two studies, thirty-one black children with biopsy-proven HBVMN were the index cases. One hundred and fifty-two family members and 43 black household contacts were the subjects of this study. We assessed HBV carrier status by testing for HBV antigens and antibodies using enzyme-linked immunosorbent assays (ELISA) and for HBV DNA by using slot-blot hybridisation and nested polymerase chain reaction. Sequencing of the precore HBV region of HBV was done in a subset of both index cases and subjects. Proteinuria was assessed by measuring the urinary protein: creatinine ratio. Seventy-two (37%) of the 197 family members and household contacts were HBV carriers, and 53 (27%) had a protein: creatinine ratio greater than the physiological limit (protein: creatinine ratio <0.2). Abnormal proteinuria was defined by a protein: creatinine ratio 0.2. Continuous data was compared using analysis of variance. Categorical data were compared using Chi-square test or Fisher’s exact test where appropriate. A probability of <0.05 was considered significant. The frequency of abnormal proteinuria was not significantly different in those with [22 (30.5%) of 72] or without [33 (32%) of 104] HBV carriage. This lack of association remained when carriers were classified into those who were HBsAg positive only and those with active viral replication (HBsAg and/or HBeAg and/or HBV DNA; p = 0.01). Family members were more predisposed to HBV carriage than household contacts, but abnormal proteinuria was present with equal frequency (p = 0.48). Age had a significant impact on proteinuria, with children less than five years being more likely to have abnormal proteinuria (p = 0.008). The prevalence of abnormal proteinuria in family members and household contacts of the index cases was more than in community-based controls. The 10 index HBVMN cases and 14 family members and household contacts that were tested all had HBV of genotype A. The results suggest that the family members and household contacts of children with HBVMN are at very high risk of HBV carriage; they also have asymptomatic proteinuria at a significantly higher rate than community-based controls. The HBV carrier status was not associated with proteinuria. This lack of association was a finding supported by peak prevalences of proteinuria in those under five years but no corresponding peak of HBV carriage. Proteinuria may indicate glomerular basement membrane dysfunction. Environmental and social factors may underpin development of these two disorders, but are insufficient to account for the index cases of HBVMN. The emergence of children with HBVMN from such households additionally depends on unidentified and possibly genetic factors [17]. In the second study of the biosocial background in which the HBV carrier-state with MN develops, we used the same subjects. One hundred and twenty-three unrelated individuals from the communities of the index cases, negative for HBV, served as controls. In this study, proteinuria was assessed using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and protein: creatinine ratios. Patterns of proteinuria on SDS-PAGE were classified as glomerular, tubular or mixed; IgG and haptoglobulin were suggestive of MN. Seventy-two (36.9%) of the 195 family members and household contacts were HBV carriers; 21 (29.2%) of these carriers had evidence of proteinuria using SDS-PAGE. Twenty-eight (41.2%) of the sixty-eight members of the study group who were HBV negative and 26.8% of the controls also showed proteinuria on SDS-PAGE. This lack of association between HBV carriage and proteinuria remained when controlled for gender and family relationship. Also, HBV was not protective against the development of proteinuria. Age was associated directly with a glomerular pattern of proteinuria (p = 0.007). Those having a pattern of proteinuria suggestive of MN were more likely to have an abnormal protein: creatinine ratio (p = 0.001). Ten (59%) subjects with a membranous pattern of proteinuria and 19 (47.5%) with a non-membranous pattern of proteinuria had microscopic haematuria. Such a pattern of proteinuria was not significantly different between subjects and community based controls (8.7% vs. 6.5%, p = 0.5). Environmental exposures in these subjects may be responsible for the proteinuria, which probably reflects underlying glomerular basement membrane damage. Discordance between the HBV carrier-state and patterns of proteinuria in the study group suggest that interaction between specifically vulnerable individuals and HBV group suggest HBV and MN may not be causally related or that it reflects exceptional interaction between specifically vulnerable individuals and HBV [18]. From the above two studies we inferred that the pathogenetic mechanisms by which individuals with chronic HBV infection develop MN are probably dependent on interactions between viral, host and environmental factors; some evidence suggests a genetic predisposition. We therefore undertook another two studies to explore HLA associations in black children with HBVMN. In the first of these two studies, thirty black children, age range 2 to 16 years, with biospy-proven HBVMN, were the subjects of this study. HLA A, B and C antigens were determined using a two-stage lymphocytotoxic test. HLA DRB1* and DQB1* typing was done using sequence-specific primers. HLA class I and II antigen frequencies of the study subjects were compared to controls that were randomly chosen healthy blood donors from the same population. HLA DQB1*0603 was increased in patients with HBVMN compared to controls (chi-square 13.65, RR 4.3). DRB1*07 and DQB1*02 were increased in frequency in the study subjects but failed to reach statistical significance. There was no significant difference in the frequencies of class I antigens in the study group compared to controls. This study is the first report of HLA associations in black patients with HBVMN in whom Class I and II antigens were determined using molecular methodology. It shows a high frequency of DQB1*0603 in black children with HBVMN compared to controls suggesting a possible genetic predisposition to the development of HBVMN [19]. Following our findings of an HLA Class II association in black children with HBVMN, we proceeded to determine if HLA DQB1*0603 predisposes to HBV carriage and development of abnormal proteinuria in the second study. We studied 70 family members of 14 children with HBVMN positive for HLA DQB1*0603 selected from the first study. Associations of HLA DQB1*0603 to HBV carriage and abnormal proteinuria were determined using the mean probability ratio (LOD scores). Forty-seven of the 70 (67%) family members were positive for HBV infection. Nineteen (27%) had abnormal range proteinuria. LOD scores in the study subjects with DQB1*0603 who were HBV negative vs. those with DQB1*0603 who were HBV positive was not significant (anti-log sum = 2.0559 and average 0.23). When a similar calculation was done for abnormal proteinuria, there were no significant findings (anti-log sum = 3.8587 and average 0.43). This lack of association between HLA DQB1*0603 with either HBV carriage or abnormal proteinuria in family members suggests that additional factors may play a role in predisposing children to chronic HBV carriage and the development of MN. We therefore conclude that the main effect of HLA DQB1*0603 which distinguishes HBVMN from family members is the degree of proteinuria which is a reflection of the severity of glomerular basement membrane damage in the latter [20]. In the next study we proceed to investigate the efficacy of Interferon alpha 2b (INTRON A ®) in the treatment of HBV-associated nephropathy in black children. Twenty-four black children with biopsy-proven HBV-associated nephropathy were recruited into the study during the period April 1997 to June 1999. Five defaulted treatment and were excluded from the primary analysis. IFN 2b was administered for 16 weeks. Response to treatment was defined as loss of HBeAg, decrease in proteinuria, and prevention of deterioration in renal and liver function. A control group of 20 patients was followed up for the same period. Ten (52.6%) of the treated children responded with clearance of HBeAg by 40 weeks. None cleared HBsAg. All responders showed remission of proteinuria, 90% maintained normal renal function and 1 (10%) showed improvement of renal function. HBV DNA levels decreased in this group. Nine patients did not clear HBeAg; none showed remission of proteinuria, 2 showed deterioration of renal function. Liver enzymes rose during treatment but subsequently declined irrespective of response to therapy. No serious side effects were encountered. Only 5% of controls showed spontaneous clearance of HBeAg, and none had remission of proteinuria. Black children with HBV-associated nephropathy show accelerated clearance of HBeAg with remission of proteinuria following treatment with IFN 2b. IFN 2b was well-tolerated [21]. We then went on to investigate the impact of HBV vaccination in South Africa over 6 years on HBV-associated MN. HBV vaccine has resulted in a decline in the incidence of HBV carriage and hepatocellular carcinoma in South East Asia. Vaccine efficacy in Africa has not been adequately assessed. King Edward VIII Hospital, Durban, South Africa, is the only tertiary referral centre for the province of KwaZulu/Natal for children with renal diseases. HBV vaccine was introduced into the Extended Programme on Immunisation (EPI) in April 1995; vaccine coverage rates between 1995-2001 for children for the first, second and third doses were 85.4%, 78.2% and 62.0% respectively. HBV status was determined using radioimmunoassay (1984 – 1991) or ELISA. MN was confirmed on renal biopsy. The hospital average annual incidence of HBVMN was compared pre and post-vaccination, and according to age groups. Between 1984 and 2001 there were 119 children with HBVMN; the mean age was 7 years (range 1 to 14 years) and 101(85%) were males. The average annual rate ratio (aRR) per 105 child population was 0.25. The aRR of 0.03 for the years 2000-2001, was significantly lower than the aRR of 0.22 during the pre-immunisation period (1984 – 1994) [p = 0.003; RR = 0.12 (95% CI: 0.03 – 0.5)]. The aRR in 2000-2001 for children 0 – 4 years (0.00) and 5 – 10 years (0.09) were significantly lower than in the pre-vaccination years (0.16 and 0.46, p = 0.01 and 0.02 respectively). Thus, HBV vaccine, even at low coverage for the full EPI schedule, reduced the hospital incidence of HBVMN by six years [22]. From this series of studies we concluded that prior to the introduction of the HBV vaccine into the Expanded Programme on Immunisation in Children, HBV-associated nephropathy, particularly MN was the commonest form of NS in black children. Several studies have suggested on the basis of epidemiological, clinical and immunological evidence a causal association between chronic HBV carriage and the development of nephropathy. In our present series of studies we have findings that lend further support to the causal association between HBV carriage and development of nephropathy, particularly MN, in black children. We have shown that genetic and other environmental factors may also play a role in determining the degree of proteinuria. Those children with abnormal range proteinuria less than the nephrotic range show no association with HBV carriage or genetic factors with regard to HLA linkage. The efficacy of interferon treatment in elimination of the HBV and abrogation of proteinuria following clearance of the virus (particularly the HBeAg) as well as the impact of routine HBV immunisation in preventing HBV carriage and subsequent development of nephropathy lends further support to our findings. The impact of viral load has yet to be investigated. / Thesis (Ph.D.)-University of Natal, Durban, 2002.