211 Virological Charactrization of HIV-1 Acute Infection by Ultra-Sensitive Next Generation Sequencing

Abstract

Aim: To establish HIV-1 RNA and proviral DNA dynamics at early times after seroconvertion, to evaluate V3 quasispecies (viral diversity and proportion of X4 variants) and to assess correlations between early quasispecies composition and clinical evolution. Methods: Nineteen HIV-acutely infected patients were enrolled within 4 wks from seroconversion (T0). Nine patients remained free of therapy, 10 started HAART according to standard guidelines. HIV RNA, proviral DNA and CD4 were monitored along a 6 month follow-up. Viral quasispecies was assessed at T0 by V3 ultra-deep pyrosequencing (UDPS); prediction of co-receptor usage was performed by PSSM. Results: At T0, HIV-1 RNA and proviral DNA were positively correlated (r=0.494, p=0.032). No correlation between HIV-1 RNA and CD4 was observed. Diversity and proportion of X4 variants were positively correlated (r=0.677, p=0.001). The median proportion of X4 variants in the circulating HIV quasispecies was 0.3% (range: 0.0- 56.25%), with only 9 out of 19 patients displaying X4 variants below 0.3%. At T0, CD4 cell counts were lower in patients who started treatment (p=0.028). In addition, a significant higher diversity was observed, at this time, in patients who underwent early treatment as compared to those who remained free of therapy (p=0.028). The decline of both HIV-1 RNA and HIV-1 DNA was significantly higher in HAART treated patients as compared to the untreated group ( p<0.001 and p=0.040). Discussion: UDPS may represent a breakthrough in the study of HIV pathogenesis, providing quantitative evaluation of viral diversity and X4 frequency in viral quasispecies. Filling of proviral DNA circulating reservoirs is an early event during acute infection and HAART is able to significantly counteract this phenomenon. The observed strong correlation between viral diversity and X4 frequency is consistent with the enrichment of X4 variants along virus evolution within each infected individual.