INTRODUCTION: Several studies have shown an association of anti-C1q antibodies (abs) with systemic lupus erythematosus (SLE) nephritis and disease activity. The aim of this study is to determine the relevance of the anti-C1q abs and the C1q levels, in Black South Africans with SLE and their relevance to disease activity and/or organ damage, specifically renal disease. METHODS: Serum anti-C1q abs and C1q levels were measured in 96 SLE patients who were also assessed for disease activity, using the SELENA Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and organ damage as measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC) Damage Index. Furthermore patients were assessed for the presence of an active urine sediment as evidenced by otherwise unexplained proteinuria, haematuria or cellular casts. Serum anti-C1q abs was measured by a commercial Elisa kit and serum C1q by immunoelectrophoresis. RESULTS: Of the 96 patients; the majority, 87 were female (90.65%), with a mean (SD) age and disease duration (SD) of 38.1 (13.0) years and 4.2 (4.4) years respectively. An active urine sediment was found in 21 (21.88%) patients. Elevated anti-C1q abs were present in 12 (12.50%) of the patients and 7 (14.29%) of the patients with renal involvement. Serum anti-C1q abs levels correlated significantly with SELENA SLEDAI scores (p=0.004, r =0.41).Anti-C1q abs levels were significantly higher in patients with an active urine sediment (p= 0.007). C1q levels were decreased in 17/96 (17.71%) patients and 11/49 (22.45%) patients with renal involvement. No associations with any other clinical features were observed. CONCLUSION: The findings indicate that in Black South Africans with SLE, although elevated anti-C1q abs levels were present in only a small minority of patients, the abs were associated with SLE global activity as determined by the SELENA SLEDAI and to the presence of an active urine sediment. These findings suggest that anti-C1q abs are a potential bio-marker of disease activity, especially active renal disease.

Systemic lupus erythematosus (SLE) is an autoimmune disorder that is characterized by the production of antibodies directed against self-antigens, such as nuclear components. Genetic analyses of lupus patients have consistently demonstrated a complex genetic basis for disease susceptibility that involves multiple genes. Identifying genes and pathways that promote disease genesis has been aided by murine studies. In particular, congenic mouse studies that examine the role of chromosomal intervals from inbred lupus-prone mouse strains on a non-autoimmune background have been useful in dissecting the genetic contribution of novel susceptibility loci in lupus pathogenesis. In this thesis, the role of New Zealand Black (NZB) chromosomes 4 and 13 are examined in non-lupus prone C57BL/6 (B6) congenic mouse strains, denoted B6.NZBc4 and B6.NZBc13, respectively. Although repeatedly mapped to contain disease augmenting alleles,NZBc4 alone was not sufficient to initiate disease, despite an expansion of NKT and B1a cells���both with controversial pathogenic roles in lupus. Instead, by crossing the B6.NZBc4 mouse with another congenic mouse strain that develops fatal lupus autoimmunity, NZBc4 was unexpectedly found to contain a suppressor locus; disease suppression was mediated by a shift away from pathogenic immunoglobulin isotypes and associated with changes in the NKT and B1a cell compartments. In contrast to the NZBc4 locus, the NZBc13 locus is sufficient to initiate polyclonal B cell activation, ANA production and mild GN, similar to NZB mice. A B cell intrinsic defect was found to be responsible for initiating the abnormal cellular phenotype in B6.NZBc13 mice. Functional analyses of the B cell subset in B6.NZBc13 mice revealed normal BCR-signaling responses and tolerance mechanisms; however, they were hyper-responsive to TLR3 stimulation, resulting in increased survival and proliferation. Thus, the study of these NZB congenic mouse strains has been instrumental in confirming the presence of loci on NZB chromosomes 4 and 13 that modulate the development of disease and highlights that disease onset is mediated by a balance of both susceptibility and suppressor alleles. Collectively, these findings contribute to the current field of lupus immunogenetics and confirm the power of congenic mouse models in understanding the genetic basis of SLE.

Systemic lupus erythematosus (SLE) is an autoimmune disorder that is characterized by the production of antibodies directed against self-antigens, such as nuclear components. Genetic analyses of lupus patients have consistently demonstrated a complex genetic basis for disease susceptibility that involves multiple genes. Identifying genes and pathways that promote disease genesis has been aided by murine studies. In particular, congenic mouse studies that examine the role of chromosomal intervals from inbred lupus-prone mouse strains on a non-autoimmune background have been useful in dissecting the genetic contribution of novel susceptibility loci in lupus pathogenesis. In this thesis, the role of New Zealand Black (NZB) chromosomes 4 and 13 are examined in non-lupus prone C57BL/6 (B6) congenic mouse strains, denoted B6.NZBc4 and B6.NZBc13, respectively. Although repeatedly mapped to contain disease augmenting alleles,NZBc4 alone was not sufficient to initiate disease, despite an expansion of NKT and B1a cells–both with controversial pathogenic roles in lupus. Instead, by crossing the B6.NZBc4 mouse with another congenic mouse strain that develops fatal lupus autoimmunity, NZBc4 was unexpectedly found to contain a suppressor locus; disease suppression was mediated by a shift away from pathogenic immunoglobulin isotypes and associated with changes in the NKT and B1a cell compartments. In contrast to the NZBc4 locus, the NZBc13 locus is sufficient to initiate polyclonal B cell activation, ANA production and mild GN, similar to NZB mice. A B cell intrinsic defect was found to be responsible for initiating the abnormal cellular phenotype in B6.NZBc13 mice. Functional analyses of the B cell subset in B6.NZBc13 mice revealed normal BCR-signaling responses and tolerance mechanisms; however, they were hyper-responsive to TLR3 stimulation, resulting in increased survival and proliferation. Thus, the study of these NZB congenic mouse strains has been instrumental in confirming the presence of loci on NZB chromosomes 4 and 13 that modulate the development of disease and highlights that disease onset is mediated by a balance of both susceptibility and suppressor alleles. Collectively, these findings contribute to the current field of lupus immunogenetics and confirm the power of congenic mouse models in understanding the genetic basis of SLE.

Diss. (sammanfattning)--Uppsala : Uppsala universitet, 2009. / Härtill 4 uppsatser.

Thesis (M.D.)--University of Hong Kong, 1987.

Thesis (M.D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 207-261).

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by disease flares and damage accrual. The increased longevity allows SLE patients to accrue damage which has retarded their survival improvement since the 1980s. In the first study of this thesis, meta-analyses of observational studies revealed that renal and neuropsychiatric damage has been adversely affecting the survival of lupus patients in the past fifty years. While confirmatory studies are required, targeting at renal and neuropsychiatric involvement early might hopefully further improve the survival of SLE patients. As the survival of SLE patients improves, their psychosocial well-being becomes increasingly important. In the second study, anxiety symptoms were found to be significantly more frequent in lupus patients than those with other common inflammatory rheumatic conditions. Additionally, damage accrual and cumulative glucocorticoids accurately predicted anxiety in SLE patients. Related to neuropsychiatric damage, event-related functional brain imaging in the third study showed that new-onset SLE patients had poorer strategic planning skill that required compensatory cortical recruitment for executing comparable cognitive function as in healthy subjects. Even after sufficient control of SLE, they remained to demonstrate inferior strategic planning skill which necessitated compensatory recruitment of cortical areas to boost their executive function. These findings illustrated that cognitive dysfunction persists even after adequate control of SLE. Early recognition of the prognostically challenging renal, cardiovascular and musculoskeletal damage and their predictors is imperative. The fourth study revealed that failure to achieve complete renal remission 12 months after renal presentation predicted renal damage, irrespective of age and the choice of immunosuppressants. As to whether mycophenolate (MMF) or cyclophosphamide (CYC) is better; by meta-analysis, the fifth study concluded that MMF offers similar efficacy as CYC in inducing renal remission and preventing renal damage. As for the cardiovascular system, endothelial dysfunction exerts its impact very early during atherogenesis. As shown in the sixth study, SLE patients na?ve for cardiovascular disease had significantly poorer endothelial function than demographically and anthropometrically matched healthy controls. Higher serum high-sensitivity C-reactive protein level independently predicted poorer endothelial function in SLE patients. Osteoporotic fracture is a major lupus musculoskeletal damage which occurred in 9% of SLE patients as found in the seventh study. Increasing age and duration of corticosteroid use independently predicted osteoporotic fracture. While hormonal replacement therapy appeared fracture protective, its unfavorable long-term consequences limit its indication for fracture prevention. Mitigating fracture risk before fractures occur is the current management strategy. The eighth study found that the significantly higher FRAX? 10-year risk of major osteoporotic and hip fractures amongst SLE patients na?ve for clinical fracture compared with their demographically and anthropometrically matched healthy counterparts was driven by chronic glucocorticoid use and premature menopause. Modifiable factors including low hip bone mineral density (BMD), cumulative glucocorticoids and higher serum anti-dsDNA level independently predicted higher fracture risks. Finally, the relationship between lumbar bone loss and endothelial dysfunction was hitherto identified. Although potential drivers of this relationship remain to be identified, our findings serve to alert physicians to early atherosclerosis in lupus patients particularly in those with low lumbar BMD. / published_or_final_version / Medicine / Master / Doctor of Medicine

Lupus nephritis is a severe organ manifestation of systemic lupus erythematosus (SLE), and is characterized by the production of anti-dsDNA antibodies. It is an important cause of renal failure. The mechanism through which anti-dsDNA antibodies bind to tissues and mediate kidney injury remains to be fully elucidated. Emerging evidence suggests that anti-dsDNA antibodies can bind to cells and extracellular antigens directly through cross-reactivity, independent of bridging chromatin material. Mesangial cells play an important role in normal kidney structure and functions, and its pathophysiology. Mesangial abnormalities in lupus nephritis precede more severe injuries such as lesions in the glomerular capillary loop. We previously demonstrated that the binding of human anti-dsDNA antibodies to mesangial cells (HMC) correlated with disease activity and induced inflammatory as well as fibrotic pathways. The aim of this project is to identify the cross-reactive antigen(s) on the mesangial cell surface that mediates anti-dsDNA antibody binding and the alterations in cell functions that result from this interaction. HMC plasma membrane proteins were purified. Using proteomic and biochemical approaches, we identified annexin II as the predominant cross-reactive antigen on the HMC surface that mediated human polyclonal anti-dsDNA antibody binding. Following this interaction, anti-dsDNA antibodies were internalized in a time- and temperature-dependent manner, and translocated to both the cytoplasm and nucleus within 30 min. This resulted in induction of annexin II synthesis, IL-6 secretion and cell proliferation, which was mediated through the activation of p38 MAPK, JNK and AKT. The binding activity to annexin II in the serum immunoglobulin fraction correlated with the titre of anti-dsDNA antibody. Binding activity of anti-dsDNA antibodies to annexin II correlated with clinical disease activity and circulating anti-dsDNA antibody levels. These correlations were more prominent in male patients with lupus nephritis. Glomerular annexin II expression was increased in patients with active lupus nephritis and co-localized with IgG and C3 deposition. Gene silencing of annexin II in HMC reduced anti-dsDNA antibody binding, which was accompanied by reduced IL-6 secretion and cell proliferation. Using female NZB/W F1 mice, an established murine model of lupus nephritis, we demonstrated that intra-glomerular annexin II expression increased with disease progression and was accompanied by an increase in the expression of p11, its cellular protein ligand. Our data suggest that annexin II may exist in the kidney as a heterotetramer and is involved in disease pathogenesis. At the ultrastructural level, annexin II was detected in the mesangial matrix, amongst electron dense deposits in the glomerular basement membrane, on the foot processes in podocytes and within the Bowman’s capsule. In conclusion, our data demonstrated that annexin II is the major cell surface antigen on HMC that mediates the cross-reactive binding of human anti-DNA antibodies. Through this interaction, cellular processes are triggered that contribute to the pathogenesis of lupus nephritis. / published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

Lupus nephritis (LN)is an important clinical manifestation of systemic lupus erythematosus (SLE)and contributes significantly to patient morbidity and mortality. In the era of effective immunosuppressive treatments, the clinical outcomes of LN patients have substantially improved, and the10-year patient and renal survival rates were98.2% and 98.0% respectively. With prolonged patient survival, infection (50.0%), cardiovascular disease (20.8%) and malignancy(12.5%)but not uncontrolled disease, have emerged as the leading causes of death in LN patients. The strongest predictor of mortalityin LN patients, however, was endstage renal disease (ESRD)as indicated by a high standardized mortality ratio of 26.1which doubled that of cardiovascular disease and history of malignancy. Despite the improved patient outcomes, conventional treatment such as cyclosphosphamide (CTX) was associated with significant toxicities and suboptimal long-term renal prognosis and hence alternative immunosuppressive agents with anti-fibrotic properties such as mycophenolate mofetil (MMF) and proliferation signal inhibitors (PSI)warrants further investigation. In Chinese patients with proliferative LN, corticosteroids and MMF as initial therapy conferred favorable long-term outcomes, with 10-year patient and renal survival of91% and 86% respectively. This regimen, when used as continuous induction-maintenance treatment, is Efficacious and well-tolerated, and the continuation of MMF treatment for at least 24 months was associated with significantly lower risk of relapse when compared to treatment for shorter duration. As the severity of tubulointerstitial fibrosis can be attenuated by growth factors with anti-fibrotic properties such as bone morphogenetic protein 7 (BMP7), hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), studies were conducted in NZB/W F1 mice to investigate the impact of treatment on intra-renal expression of growth factors pertinent to fibrosis. Methylprednisolone (MP) combined with either MMF or CTX have resulted in increased BMP7 and reduced HGF and VEGF in the renal parenchyma, reduced fibrosis, and improved clinical parameters, compared with MP alone. The data also suggested that the increase in BMP7, a potentially anti-fibrotic cytokine, was observed earlier in the mice treated with MMF compared with those treated with CTX. Our preliminary clinical experience also suggested that PSI combined with corticosteroids may serve as an efficacious and well-tolerated immunosuppressive regimen in human LN, especially in patients with MMF intolerance or history of malignancy. These observations have important implications on the choice of therapy for the treatment of proliferative LN. As for membranous LN, our pilot results suggested that corticosteroids combined with either MMF or tacrolimus can be effective treatment options for patients with significant proteinuria, while each regimen exhibits distinct efficacy and tolerability profiles. In conclusion, the results from the studies included in this thesis show the magnitude of benefit conferred by novel immunosuppressive treatment regimens for LN on renal and patient survival, and on the associated intra-renal mechanisms pertaining to fibrosis. / published_or_final_version / Medicine / Master / Doctor of Medicine

published_or_final_version / Medicine / Master / Doctor of Medicine