Seroprevalence and Viral Characterization in Two Voluntary TesTing Centres, Buenos Aires City, Argentina

DARÍO ALBERTO DILERNIA; LEONARDO LOURTAU; RUBÉN MARONEANA MONCZOR; MARCELO LOSSO; HORACIO SALOMÓN

Montreal, Québec, Canadá

Congreso; AIDS Vaccine 2005: Together, a better future for all.; 2005

Objective: To analyse the frequency of the newly-diagnosed HIV-infected individuals and to evaluate viral variants at two voluntary testing centers in the city of Buenos Aires. Methods: HIV-testing results from 2404 individuals who assisted two voluntary testing centers (a Public Hospital and a Gay Men NGO) in the city of Buenos Aires were included in the study of sequential selection in the order in which they appeared for HIV-testing between March 2003 and January 2005. Blood samples from those with positive result (newly diagnosed) were collected and HIV pol gene was genotyped from plasma viral RNA by automated sequencing. Viral subtype characterizations were performed by phylogenetic analysis (alignment by Clustal W (BioEdit), codon optimization (GeneCutter), Neighbor-joining trees (MEGA2), similarity plotting and boostcanning (Simplot 2.5)). Results: We found a seroprevalence significantly different between sites (8.2% (50/609) at the Public Hospital and 4.7% (85/1795) at Gay Men NGO, p0.05). 128 samples were successfully sequenced in the pol gene and the filogenetic analysis showed that 53 out of them were subtype B variants, 65 were BF recombinant variants and 10 were unusual nonB-nonBF variants. The aminoacidic variability analysis across the viral region amplified showed that all the sequences considered together had the same variability when compared with only those of subtype B except in 7 regions of 9-15 aminoacids residues were variability was higher in the first group. 5 out of them correspond to regions previously identified as CTL epitopes. Conclusions: This work shows that the frequency of new diagnosed individuals was significantly different between the two centers. On the other hand, we demonstrated that the presence of BF recombinant variants increase the variability in regions recognized as CTL epitopes, suggesting that the design of vaccines in our region could be more complex than in regions were only subtype B variants are circulating.