Thesis (MScMedSc) -- Stellenbosch University, 1998. / Bibliography / ENGLISH ABSTRACT: There is a progressive maturation of the immune system from infancy to adulthood. The
immature immune system in early life is characterised by impaired macrophage function
and antigen presentation as well as a higher naIve to memory T cell ratio with subsequent
diminished IFN-y production. Children with tuberculosis often present with
lymphadenopathy, the complications thereof or with systemic spread of the organisms.
Adults generally manifest with pronounced systemic effects (such as weight loss and high
fever) and immunopathology (such as cavitation and fibrosis). We hypothesised that the
immunopathology in adults may be due to enhanced cytokine production in comparison
to children. The first aim of this study was therefore to measure cytokine responses in
healthy children and adults. Cytokine responses in patients with tuberculosis will be
examined in future studies. Peripheral blood mononuclear cells (PBMC) were isolated
from whole blood obtained from 9 healthy children and 9 healthy adults. The cells were
cultured in serum-free medium, unstimulated or polyclonally stimulated with
Phytohaemagglutinin (PHA). Supernatants were harvested after which IFN-y, IL-2,
TNF-a., IL-4 and IL-IO production was determined by means of ELISA analysis. Ri'J"A
was ~ubsequently extracted from the cells followed by RT-PCR analysis for the semiquantitative
determination of mRNA levels of these cytokines. PBMC isolated from
healthy children produced significantly less IFN-y protein than adults. Futhermore, IFN-y
production in the adults seemed to be trimodally distributed. No significant differences
could be found in the production of IL-2, TNF-a, IL-4 and IL-] O. Although children
produced low levels of IFN-y protein, their IFN-y, TNF-a, IL-2, IL-4 and IL-IO mRNA
levels were comparable to that of adults.
Tuberculosis is a major cause of mortality and morbidity, particularly in the third world.
Ravensmead and Uitsig, two adjacent suburbs in the Western Cape, have a tuberculosis
incidence of> I 000/100000 population. Also, up to 90 % of the children in the Western
Cape have been reported to be infested by intestinal parasites such as Ascaris
lumbricoides and Trichurius trichl/ria. Infection with M tuberculosis indut:es a Th 1
Stellenbosch University http://scholar.sun.ac.za
iv
In:.,c response, while intestinal parasites elicit a Th2 immune response. Th2
dominance induced by intestinal parasite infestations could predispose individuals to an
enhanced susceptibility to M. tuberculosis. The second aim of this study was to
investigate serum IgE levels, surrogate markers for Th2 activation, in the community.
The serum 19B levels were subsequently correlated to the tuberculosis incidence per
enumerator sub-district (ESD), crowding, female literacy and socio-economic levels. Similarly, the tuberculosis incidence per ESD was correlated with the above mentioned
parameters. A significant positive correlation was found between tuberculosis incidence
and the serum 19E levels in the community. However, further studies are needed to
determine if intestinal parasites are the main cause of the high 19B levels in the
community and to dCh111ine if parasite loads or Th2 dominance are causally linked to the
incidence of tuberculosis. Correlation between serum 19E levels and tuberculosis
incidence with the other parameters were significant, except in the case of crowding.
The third aim of this study was to measure serum IgE and specific 19E levels against
Ascaris and common allergens on presentation of tuberculosis and again after completion
of successful treatment. Significant declines in serum 19B and Ascaris specific 19B levels
were observed after completion of tuberculosis treatment. This down regulation of IgE
levels may be due to an up regulation of ThI responses in patients following successful
treatment for tuberculosis. / AFRIKAANSE OPSOMMING: Die immuunsisteem matureer toenemend vanaf kinderjare tot en met volwassewording.
Die onvolwasse immuunsisteem van jong kinders word gekenmerk deur verswakte
makrofaag-funksionering en antigeenpresentering, sowe) as 'n verhoogde naiwe tot
geheue T-sel verhouding met gevolglikc verminderde IFN-y produksie. Kinders met
tuberkulose presenteer gewoonlik met Iimfadenopatie, komplikasies daarvan of met
gedissemineerde siekte. Volwassenes presenteer met sistemiese gevolge (soos
gewigsverlies en hoe koors) en immunopatologie (soos kavitasie en fibrose). Ons
hipotese is dat die immunopatologie in volwassenes die gevolg is van 'n verhoogde
sitokienproduksie in vergelyking met kinders. Die eerste doelwit van die studie was om
sitokienproduksie in gesonde kinders en volwassenes te meet. Sitokienproduksie in
tuberkulose pasiente sal in 'n opvolgstudie bepaal word. Perifere bloed mononukleere
selle was geisoleer vanuit heel bloed verkry vanaf 9 gesonde kinders en 9 gesonde
volwassenes. Die selle was gekweek, ongestimuleer of gestimuleer met
Phytohaemagglutinien (PHA). Supernatante was geoes vir die bepaling van IFN-y, IL-2,
IL-4, IL-I0 en TNF-a. produksie, deur gebruik te maak van ELISA analise. RNA was
gevolglik vanaf die selle ge-ekstraheer vir die tru-transkriptase polimeerketting reaksie
analise, waartydens sitokien mRNA vlakke op 'n semi-kwantitatiewe wyse bepaal was.
Perifere bloed mononukleere selle geisoleer vanaf die kinders het minder IFN-y
geproduseer as die van volwassenes. Hierdie verminderde produksie was hoogs
betekenisvol. Dit wou voorkom asof die IFN-y produksie deur volwassenes trimodaal
versprei was. Geen betekenisvolle verskille tussen kinders en volwassenes kon gevind
word in die produksie van IL-2, IL-4, IL-IO en TNF-a nie. Alhoewel kinders minder
IFN-y proteien geproduseer het, het hulle IFN-y, IL-2, IL-4, IL-JO en TNF-a mRNA
produksie met vlakke van volwassenes ooreengestem.
Tuberkulose speel 'n groat rol in morbiditeit en mortaliteit in veral die derde wereld.
Ravensmead en Uitsig, twee aangrensende voorstede in die Wes-Kaap, het 'n tuberkulose
voorkomssyfer van> 1 000/1 00000 populasie. Verder, is tot 90 % van die kinders in die
Stellenbosch University http://scholar.sun.ac.za
VI
Wes-Kaap gei'nfesteer met intestinale parasiete soos Ascaris Ilimbricoides en Trichllrills
trichllria. M. tuberculosis infeksie induseer 'n Thl immuunrespons, terwyl intestinale
parasiete 'n Th2 immuunrespons uitlok. 'n Dominante Th2 respons mag moontlik
individue predisponeer tot 'n verhoogde vatbaarheid vir M. tuberculosis. Gevolglik was
die tweede doelwit van die studie om serum IgE vlakke as surrogaat merkers vir Th2
aktivering in die gemeenskap bestudeer. Die serum IgE vlakke was gevolglik gekorreleer
met die tuberkulose voorkoms per opnemerssensusgebied (OSG), saamdringing, vroulike
geletterdheid en sosio-ekonomiese vlakke. Die tuberkulose voorkoms per OSG, is op
dieselfde wyse gekorreleer met die bogenoemde parameters. 'n Betekenisvolle positiewe
korrelasie is gevind tussen tuberkulose voorkoms en serum IgE vlakke in die
gemeenskap. Verdere stuciies is egter nodig om te bepaal of intestinale parasiete weI die
oorsaak van die hoe IgE vlakke in die gemeenskap is en of parasiet ladings of Th2
dominansie oorsaaklik verbind kan word aan die tuberkulose voorkoms.
Die derde doelwit van die studie was om serum 19E en spesifieke IgE vlakke teen Ascaris
en algemene allergene te meet met presentering van tuberkulose en weer na voltooing
van suksesvolle behandeling. 'n Betekenisvolle afname in serum 19E en Ascaris
spesifieke 19E vlakke is waargeneem na vohooing van tuberkulose behandeling. Die
afregulering van 19E vlakke kan moontlik toegeskryf word aan die opregulering van Th1
response in pasi"ente na voltooing van suksesvolle behandeling van tuberkulose.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/70225 |
| Date | 12 1900 |
| Creators | Adams, Joanita Frances Ann |
| Contributors | Beyers, A. D., Stellenbosch University. Faculty of Medicine & Health Sciences. Dept. of Biomedical Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | xxiii, 146 p. : ill. |
| Rights | Stellenbosch University |
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