Thesis (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Renal transplantation is undoubtedly the best treatment for patients with
irreversible renal failure. As a prelude to establishing the nature of
malignancies in renal transplant patients we sought to determine factors
influencing the outcome of renal transplantation. The survival of renal allografts and
of recipients is influenced by a number of demographic, clinical and therapeutic
factors. Some of these factors have been better studied than others, and we sought
to establish the influence of particular factors on our own patients and allografts.
The total number and nature of malignancies developing in these patients
subsequent to transplantation was also established.
All patients transplanted in our unit between April 1, 1976 and March 31, 1999 were
included in the study. In the study period, 542 patients received 623 renal allografts.
Demographic details were analysed. Patient and graft outcomes were assessed
using Kaplan-Meier survival analysis. The survival curves were compared using
univariate analysis; results that were significant were subjected to multivariate
analysis. The influence of a number of factors on graft and patient survival were
assessed and compared. The impact of a variety of variables on the number and
behaviour of malignancies was also established. Patient and graft survival were superior in recipients who were aged less than 40
years; cyclosporine improved graft survival but not patient survival. Early graft loss
was associated with a high patient mortality rate. Contrary to the experience
elsewhere, black and white patients had similar outcomes after renal transplantation.
Of the 542 recipients 41(8.1%) developed malignancies with Kaposi's sarcoma
occurring, in 21 patients and skin cancers in 13 patients. The relative risk for the
Kaposi's sarcoma development was 235. Kaposi's sarcoma was the most common
tumour in non-white patients (accounting for 79% of malignancies in this group) and
occurred less than 2 years after transplantation. Kaposi's sarcoma was equally
common in male and female recipients. Under cyclosporine the latent period to
malignancies was reduced but the frequency remained unaffected. Kaposi's
sarcoma skin lesions were present in all the affected patients, with the lower limbs
the most common site of involvement. Kaposi's sarcoma responded to reduction of
immunosuppression without the need for complete discontinuation, and with
preservation of renal function. Extracutaneous involvement occurred in over one
quarter of the patients and invariably proved fatal in all patients with visceral organ
involvement. The histopathology of posttransplant Kaposi's sarcoma was the same
as that described in the other epidemiological forms of the disease.
White male recipients were at the greatest risk of developing skin cancers after renal
transplantation. Squamous cell carcinomas were relatively more common and were
found in sun-exposed areas. The lesions were treated only by local excision and
none metastasized. Malignant lymphoma, breast cancer and lung cancer occurred
in individual patients but the relative risk of all these lesions were close to unity.
Patients with preexisting cancers did not develop recurrences following
transplantation.
SECTION 2
Both immunosuppression and immunostimulation are thought to play a role in the
development of Kaposi's sarcoma after renal transplantation. We investigated the
quantitative and qualitative aspects of the immune system of patients who had
developed Kaposi's sarcoma. The lymphocyte phenotypes were established using flow cytometry while
transformation studies were performed using mitogens. Pokeweed was used as the
B-cell mitogen, and concanavalin A and phytahaemagglutinin were the T-cell
mitogens. Cell mediated immunity was also tested using delayed type
hypersensitivity skin tests and the serum immunoglobulin levels were estimated.
Firstly, with regard to humoral immunity, 2/3 of the patients had normal serum
immunoglobulin levels, although the B-cell count was reduced in all the patients on
immunosuppression. B-cell transformation tests with pokeweed mitogen revealed
that B-cell function was not impaired in patients with Kaposi's sarcoma. The patients
with decreased immunoglobulin levels also appeared to be malnourished as
evidenced by low albumin levels. Secondly, CD3 and CD4, but not CD8, cell counts
were reduced in patients with Kaposi's sarcoma. The transformation analyses
revealed significant differences compared to controls, with reduced responses in
patients with Kaposi's sarcoma. Thirdly, natural killer (NK) cell numbers were also
reduced in patients with Kaposi's sarcoma. There were no significant differences in
delayed type hypersensitivity skin reactions that could not be accounted for by racial
differences.
Cellular immunity is impaired in patients with Kaposi's sarcoma with a reduction in
the number of NK cells. Both of these components of the immune system are
important in protection against malignant transformation.
SECTION 3
Kaposi's sarcoma is an important complication of renal transplantation. If the human
herpesvirus 8 (HHV-8) causes Kaposi's sarcoma, the virus should be present in all
Kaposi's sarcoma lesions and be drastically reduced or cleared from involved tissue
on remission of the Kaposi's sarcoma.
Fourteen renal transplant patients with cutaneous Kaposi's sarcoma, including
autopsy material from two cases, were investigated for the presence of HHV-8. A
second skin biopsy was taken from 11 survivors, after remission of Kaposi's
sarcoma, from normal skin in the same anatomical region as the first biopsy. Remission was induced by reduction or cessation of immunosuppression. A
peripheral blood sample was collected simultaneously with the repeat biopsy. A
nested polymerase chain reaction assay was used to detect HHV-8 DNA in the
biopsy tissue and peripheral blood mononuclear cells followed by direct sequencing
of polymerase chain reaction product to detect any nucleotide changes.
HHV-8 DNA was detected in all the cutaneous Kaposi's sarcoma and all the visceral
Kaposi's sarcoma samples, as well as a number of Kaposi's sarcoma-free organs
including the thyroid, salivary gland, and myocardium that have not been described
before. Mutations in the viral DNA could be demonstrated in all patients. The
mutations found were related more to that seen in AIDS-Kaposi's sarcoma cases
than that found in African endemic Kaposi's sarcoma cases. HHV-8 sequences
could be detected in follow-up frozen skin biopsies of five patients but were negative
in the equivalent formalin-fixed specimens. Viral DNA was also detected in 2 of 11
peripheral blood mononuclear cell samples collected at the time of the follow-up skin
biopsies.
Reduction or withdrawal of immunosuppression allows the immune system to
recover sufficiently to reduce viral replication with subsequent viral persistence and
low-grade viral replication that coincides with clinical remission of the Kaposi's
sarcoma lesions. This provides further evidence for the important etiological role
played by HHV-8 in the pathogenesis of posttransplant Kaposi's sarcoma.
SECTION 4
The recently discovered HHV-8 is an important factor in the aetiopathogenesis of
Kaposi’s sarcoma. The reason for the exceptionally high prevalence of Kaposi's
sarcoma in our area, as well as that of other developing countries, remains
unexplained. We investigated the seroprevalence of the virus in the different healthy
subjects as well as organ donor-recipient pairs.
All recipients were tested at the time of transplantation, as were the paired donors.
Control subjects tested were healthy blood donors, Renal Unit staff, and household
contacts of patients with Kaposi's sarcoma. An enzyme-linked immunoassay (ELISA) to the whole virus was used for screening and all positives were confirmed
using ELISA to the latent ORF 73 antigen.
The prevalence of HHV-8 was similar in all groups and averaged less than 6%. After
transplantation the seroprevalence increased to almost 20% but neither the
transplanted kidney nor blood transfused perioperatively could account for the
increase. Kaposi's sarcoma developed in 3 of the 116 patients transplanted. All
patients with Kaposi's sarcoma were proven to be HHV-8 seropositive before the
development of the disease. Two of the patients who developed Kaposi's sarcoma
were seropositive before transplantation. No patient who received a graft from a
seropositive donor developed Kaposi's sarcoma.
We refute the notion that a high prevalence of HHV-8 in the general population is
responsible for the high prevalence of Kaposi's sarcoma in our population or that the
donor organ is a major source of infection in renal transplant recipients.
Reactivation, rather than primary infection appears to be the source of the virus after
renal transplantation. / AFRIKAANSE OPSOMMING: Nieroorplanting is ongetwyfeld die beste behandeling vir pasiente met
onomkeerbare nierversaking. As ‘n aanloop om die aard van maligniteite
in nierooorplantingspas'fente vas te stel het ons gepoog om die faktore wat
die uitkoms van nieroorplantings bemvloed te bepaal. Die oorlewing van
oorgeplante niere en van nierontvangers word deur ‘n aantal demografiese, kliniese
en terapeutiese faktore bemvloed. Sommige van hierdie faktore is beter ondersoek
as ander and ons het gepoog om die invloed van sekere faktore op ons eie pasiente
en oorgeplante niere te bepaal. Die getal en aard van maligniteite wat ontwikkel het
in hierdie pasiente na nieroorplanting is ook gedokumenteer.
Alle pasiente in ons eenheid in wie ‘n nier tussen 1 April 1976 en 31 Maart 1999
oorgeplant was, is in die studie ingesluit. Tydens die studieperiode het 542 pasiente
623 niere ontvang. Demografiese detail is ontleed. Pasient- en nieroorplantings
uitkomste is beraam deur gebruik te maak van Kaplan-Meier oorlewing analiese.
Die oorlewingskurwes is vergelyk deur gebruik te maak van enkelveranderlike
ontledings; noemenswardige resultate is onderwerp aan meerveranderlike
ontledings. Die invloed van ‘n aantal faktore op oorgeplante nier- en
pasientoorlewing is ondersoek en vergelyk. Die impak van ‘n verskeidenheid
veranderlikes op die getal en gedrag van maligniteite is ook ondersoek. Pasient oorlewing asook oorlewing van oorgeplante niere was beter in ontvangers
onder die ouderdom van veertig jaar. Vroee verlies van ‘n oorgeplante nier het
verband gehou met ‘n hoe pasientmortaliteit. Siklosporien het die oorlewing van
oorgeplante niere verbeter, maar nie die van pasiente nie. In teenstelling met die
ervaring elders, het swart en wit pasiente soortgelyke uitkomste uitkoms gehad na
‘n nieroorplanting.
Van die 542 ontvangers, het 41 (8.1%) maligniteite ontwikkel; Kaposi se sarkoom het
in 21 pasiente voorgekom en velkanker in 13 pasiente. Die relatiewe risiko (“relative
risk") vir die ontwikkeling van Kaposi se sarkoom was 235. Kaposi se sarkoom was
die algemeenste tumor in swart en gekleurde pasiente (verantwoordelik vir 79% van
maligniteite in die groep) en het binne twee jaar voorgekom. Kaposi se sarkoom
was ewe algemeen in manlike en vroulike ontvangers. Met behandeling deur middel
van siklosporien het die latente periode totdat maligniteite ontwikkel het verkort,
maar die insidensie daarvan het onveranderd gebly. Velletsels geassosieer met
Kaposi se sarkoom was teenwoordig in alle pasiente met die vel van die onderste
ledemate die mees algemeen betrokke ligging. Die sarkoom het gereageer op
vermindering van immuunonderdrukking, sonder die nodigheid vir volkome
onttrekking, en met die bewaring van nierfunksie. Ekstrakutane betrokkenheid het
in meer as ‘n kwart van die pasiente voorgekom en was altyd noodlottig in pasiente
met viserale aantasting. Die histopatologie van postoorplanting Kaposi se sarkoom
was dieselfde as die wat beskryf is vir die ander epidemiologiese vorms van die
siekte.
Wit mans het die hoogste risiko vir die ontwikkeling van velkankers na
nieroorplanting gehad. Plaveiselsel karsinoom was betreklik meer algemeen en het
in son-blootgestelde areas voorgekom. Die letsels was uitsluitlik met lokale eksisie
behandel en geen pasiente het metastases ontwikkel nie. Maligne limfoom,
borskanker, en longkanker het in enkele pasiente voorgekom maar die relatiewe
risiko van al die letsels was om en by een gewees. Nie een van die pasiente met
vorige maligniteite het herhaling van die tumore na oorplanting ontwikkel nie. AFDELING 2
Die vermoede is dat beide immuunonderdrukking en immuunstimulasie ‘n rol speel
in die ontwikkeling van Kaposi se sarkoom na ‘n nieroorplanting. Ons het die
kwantitiewe en kwalitatiewe aspekte van die immuunsisteem van pasiente wat
Kaposi se sarkoom ontwikkel het na ‘n nieroorplanting, ondersoek .
Limfosiet fenotipes is met behulp van vloeisitometrie bepaal, terwyl
transformasiestudies uitgevoer is deur gebruik te maak van mitogene. “Pokeweed”
is gebruik as die B-sel mitogeen, en konkanavalien A en fitaheemagglutinien was die
T-sel mitogene. Sel-gemedieerde immuniteit was ook getoets deur die gebruik van
vertraagde tipe hipersensitiwiteit veltoetse. Die serum immunoglobulien vlakke was
ook bepaal.
Eerstens, met betrekking tot humorale immuniteit, het 2/3 van die pasiente normale
serum immunoglobulienvlakke gehad, alhoewel die B-seltelling verminder was in al
die pasiente op immuunonderdrukking. B-seltransformasie-toetse met “pokeweed”
mitogeen het getoon dat B-sel funksie nie ingekort was in pasiente met Kaposi se
sarkoom nie. Die pasiente met verminderde serum immunoglobulinvlakke het ook
wangevoed voorgekom soos die verlaagde serum albumienvlakke uitgewys het.
Tweedens was CD3 en CD4 seltellings, maar nie CD8 nie, verlaag in pasiente met
Kaposi se sarkoom. Betekenisvolle verskille is ook aangetoon met T-sel
transformasietoetse in vergelyking met kontroles, met verminderde response in
Kaposi se sarkoom pasiente. Derdens was natuurlike dodersel (NK) getalle ook
minder in pasiente met Kaposi se sarkoom. Daar was geen noemenswaardige
verskille in vetraagde tipe hipersensitiwiteit velreaksies wat nie deur rasseverskille
kon verklaar word nie.
Sellulere immuniteit is ingekort in pasiente met Kaposi se sarkoom met ‘n verlaging
in die aantal NK selle. Beide die komponente van die immuunstelsel is belangrik vir
beskerming teen maligne transformasie. AFDELING 3
Kaposi se sarkoom is ‘n belangrike komplikasie van nieroorplanting. As die menslike
herpesvirus-8 (HHV-8) Kaposi se sarkoom veroorsaak, behoort die virus
teenwoordig te wees in alle letsels en as Kaposi se sarkoom remissie ondergaan
behoort dit drasties te verminder of te verdwyn in weefsel waarin dit voorkom.
Veertien nieroorplantingspasiente met Kaposi se sarkoom van die vel, insluitend
outopsiemateriaal van twee gevalle, is ondersoek vir die teenwoordigheid van HHV-
8. ‘n Tweede velbiopsie van dieselfde anatomiese area as die eerste is uitgevoer op
11 oorlewende pasiente na remissie van die sarkoom. Remissie was deur die
vermindering of onttrekking van immuunonderdrukking bewerkstellig. ‘n Perifere
bloedmonster is by dieselfde geleentheid as die tweede biopsie geneem. ‘n Geneste
polimerase kettingreaksietoets (“nested polymerase chain reaction”) is gebruik om
die teenwoordigheid van HHV-8 DNA in die biopsieweefsel en perifere bloed
mononukluere selle te bepaal, gevolg deur direkte volgordebepaling (“sequencing”)
van die polimerase kettingreaksieproduk om enige nukleotiedveranderings te
dokumenteer.
HHV-8 DNA is waargeneem in al die kutane Kaposi se sarkoom en al die viserale
Kaposi se sarkoom monsters, sowel as in weefsel waar die Kaposi se sarkoom nie
voorgekom het nie en waar die teenwoordigheid van die virus nie tevore beskryf is
nie, soos die skilklier, speekselklier, en hartspier. Mutasies in die virale DNA kon in
alle pasiente aangetoon word. Die mutasies wat gevind is, was nader verwant aan
die wat in VIGS-Kaposi se sarkoom beskryf is as die wat in endemiese Kaposi se
sarkoom in Afrika gevind word. HHV-8 volgordes kon waargeneem word in bevrore
opvolg-velbiopsies van vyf pasiente, maar was afwesig in die ekwivalente formaliengefikseerde
monsters. Virus DNA is ook waargeneem in 2 van 11 perifere bloed
mononukluere selmonsters wat versamel is tydens die opvolg velbiopsies.
Vermindering of onttrekking van immuunonderdrukking laat die immuunsisteem toe
om genoegsaam te herstel om virale replikasie te verminder met daaropvolgende
teenwoordigheid en laegraadse virale replikasie wat ooreenstem met kliniese
remissie van letsels van Kaposi se sarkoom. Dit verskaf verdere bewyse van die belangrike oorsaaklike rol wat deur HHV-8 gespeel word in die patogenese van
postoorplanting Kaposi se sarkoom.
AFDELING 4
Die onlangs-ontdekte HHV-8 is ‘n belangrike faktor in die etiopatogenese van Kaposi
se sarkoom. Die rede vir die buitengewone hoe prevalensie in ons gebied, sowel as
die van ander ontwikkelende lande, is nie voor die hand liggend nie. Ons het die
seroprevalensie van die virus in verskillende gesonde persone, sowel as orgaan
donor-ontvanger pare ondersoek.
Alle nierontvangers en hul gepaarde donors is getoets ten tye van die
nieroorplanting. Getoetste kontrole persone was gesonde bloedskenkers,
niereenheid personeel en huishoudlike kontakte van pasiente met vorige Kaposi se
sarkoom. ‘n Ensiemgekoppelde immuuntoets (enzyme-linked immnoassay; ELISA)
vir die volledige virus was gebruik vir sifting en bevestiging is verkry vir alle positiewe
toetse deur gebruik te maak van van ‘n ELISA vir die latente ORF 73 antigeen.
Die prevalensie van HHV-8 was vergelykbaar in alle groepe en was gemiddeld
minder as 6%. Na oorplanting het die prevalensie gestyg tot byna 20%, maar nog
die oorgeplante nier nog perioperatiewe bloedoortappings kom die styging verklaar.
Kaposi se sarkoom het in 3 van 116 van die pasiente wat ‘n oorplanting ondergaan
het, ontwikkel. Al die pasiente met Kaposi se sarkoom was HHV-8 seropositief voor
die ontwikkeling van die Kaposi se sarkoom. Twee van die pasiente wat Kaposi se
sarkoom ontwikkel het was seropositief voor die oorplanting. Geen pasient wat ‘n
nier van ‘n seropositiewe donor ontvang het, het Kaposi se sarkoom ontwikkel nie.
Ons weerle die stelling dat ‘n hoe prevalensie van HHV-8 in die algemene bevolking
verantwoordelik is vir die hoe prevalensie van Kaposi se sarkoom onder ons
nieroorplantingspasiente of dat die donornier ’n belangrike bron van infeksie is. Dit
wil voorkom of heraktivering, eerder as primere infeksie, ‘n bron van die virus is na
nieroorplanting.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/53101 |
| Date | 03 1900 |
| Creators | Moosa, M. R. |
| Contributors | Du Toit, D. F., Wranz, P. A. B., Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Anatomical Pathology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 2 v. : ill. |
| Rights | Stellenbosch University |
Page generated in 0.0053 seconds