Investigating HIV-1 DNA and HIV-1 RNA kinetics with ultrasensitive assays in very early treated infants and determining predictors associated with kinetics in older treated children

Veldsman, Kirsten Abigail (2019-12)

Thesis (MSc)--Stellenbosch University, 2019.

Thesis

Background The impact of early initiation of antiretroviral therapy (ART) on HIV-1 persistence has been characterised in adult cohorts and in well-suppressed children on continuous therapy. These studies have shown that early ART initiation may limit the size of the latent HIV reservoir that is established early in infection. Early initiation of therapy causes a more rapid decay of infected cells and may increase the probability of post-treatment control which is valuable for HIV-1 remission strategies. However, there remains limited information from longitudinal studies from resource limited settings especially investigating the effects of therapy initiation within days of birth on HIV-1 DNA and viral decay kinetics. Our aims were to investigate total HIV-1 DNA and HIV-1 RNA decay in very early treated infants and in older treated children who underwent therapy interruption and to determine potential predictors influencing decay. Methods Participants were selected from two cohorts; eleven infants from a public health sector birth diagnosis program who initiated ART at median of four days and 31 children from a clinical trial study where children were randomised to elective time-limited therapy or delayed continuous therapy. Peripheral blood mononuclear cells (PBMCs) were processed at scheduled study visits and plasma viral load measured using commercial diagnostic assays. Following DNA extraction from PBMCs, total HIV-1 DNA was quantified using a sensitive real-time PCR assay adapted for HIV-1 subtype C targeting a conserved region in the HIV-1 genome (integrase gene). Generalised linear and mixed effect regression models; and Spearman rank correlations were used to study decay and associating predictors. Statistical tests were implemented in R software version 3.4.3. Results In our study we observed that infants who initiated therapy at around five days had a faster decay rate than children who initiated ART at around five months of age, the half-life (t ½) HIV-1 DNA was 2.7 months and 9.2 months, respectively. In the multivariate model, high pre-treatment HIV-1 DNA level (p<0.001) and an increase in HIV-1 DNA concentration during the period of therapy interruption (p<0.01) were independent significant predictors of slower subsequent HIV-1 DNA decay. In contrast, children who received prolonged initial treatment for 96 weeks had a faster decay after reinitiating on therapy (p=0.02). Conclusion This study provided some of the first longitudinal data of HIV-1 DNA decay in children from a resource limited setting. We suggest early treatment as an important modifiable factor in determining HIV-1 DNA decay. Furthermore, we show that very early diagnosis and subsequent therapy initiation, when achieving adequate virological suppression, in the early stages of infection may be valuable in limiting the persistence of long-lived HIV-1 infected cells.

AFRIKAANSE OPSOMMING: Die impak van vroeë inisiasie van antiretrovirale terapie (ART) op MIV-1-voortbestaan is gekenmerk in volwasse kohorte en in goed-onderdrukte kinders tydens volgehoue terapie. Hierdie studies het getoon dat vroeë ART-aanvang die grootte van die latente MIV-reservoir wat vroeg in infeksie gevestig word, kan beperk. Vroeë terapie aanvang veroorsaak 'n vinniger verval van geïnfekteerde selle en kan die waarskynlikheid van na-behandeling beheer, wat waardevol is vir MIV-1 remissie strategieë, verhoog. Daar bly egter beperkte inligting van longitudinale studies van hulpbronbeperkte instellings, veral om die gevolge van terapieinisiëring binne dae van geboorte op MIV-1 DNs en virale vervalkinetika te ondersoek. Ons doelwitte was om die totale MIV-1 DNS en MIV-1 RNS verval in baie vroeë behandelde babas en in ouer behandelde kinders wat terapie onderbreek het, te ondersoek en om te bepaal die potensiële voorspellers wat die verwal beïnvloed. Metodes Deelnemers is gekies uit twee kohorte; elf babas van 'n geboortediagnose-program vir openbare gesondheidsorg wat ART begin het teen `n mediaan van vier dae en 31 kinders van 'n kliniese proefstudie waar kinders gerandomiseer is vir elektiewe tydbeperkende terapie of uitgestelde volgehoue terapie. Perifere bloed mononukleêre selle (PBMS's) is geprosesser tydens geskeduleerde studiebesoeke en plasma virale lading gemeet met kommersiële diagnostiese toetse. Na DNA-ekstraksie van PBMS's, is die totale MIV-1 DNA gekwantifiseer met behulp van 'n sensitiewe real-time PKR-bepaling aangepas vir MIV-1 subtipe C wat 'n min-varierende gebied in die MIV-1-genoom (integrasegeen) teiken. Algemene lineêre en gemengde effek regressie modelle; en Spearman rangkorrelasies is gebruik om verval te bestudeer en voorspellers te assosieer. Statistiese toetse is geïmplementeer in R sagteware weergawe 3.4.3. Resultate In ons studie het ons opgemerk dat babas wat terapie teen ongeveer vier dae begin het, 'n vinniger verval gehad het as kinders wat ART teen ongeveer vyf maande begin het. Die MIV-1 DNA halfleeftyd (t ½) was onderskeidelik, 2.7 maande en 9.2 maande. In die multivariate model was hoë voor-behandeling MIV-1 DNA vlak (p <0.001) en 'n toename in MIV-1 DNA konsentrasie gedurende die periode van terapie onderbreking (p <0.01) onafhanklike belangrike voorspellers van stadiger daaropvolgende MIV-1 DNA verval. In teenstelling hiermee, het kinders wat langdurige aanvanklike behandeling gedurende 96 weke ontvang het, 'n vinniger verval ná terapie re-inisiasie (p = 0,02). Gevolgtrekking Hierdie studie het van die eerste longitudinale data van MIV-1 DNA-verval in kinders uit 'n hulpbron beperkte omgewing gelewer. Ons stel vroeë behandeling as 'n belangrike wysigbare faktor in die bepaling van MIV-1 DNA-verval voor. Verder wys ons dat baie vroeë diagnose en die daaropvolgende terapie-aanvang met voldoende virale onderdrukking, in die vroeë stadiums van infeksie, waardevol kan wees om die voortbestaan langlewende MIV-1-geïnfekteerde selle te beperk.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/107330
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