Is there a relationship between the transmission route and hiv-1 subtypes in Argentina?.

AVILA MM; GOMEZ CARRILLO M; VIGNOLES M; PANDO MA; MARTINEZ PERALTA L; SANCHEZ J; MONTANO S; WEISSENBACHER M

La Habana

Otro; II Foro en VIH/SIDA/ITS de América Latina y el Caribe.; 2003

Introduction: AIDS epidemic in Argentina is mainly associated with injecting drug use (IDU) (40%), men who have sex with men (MSM) (26%) and heterosexual men and women (HMW) (28%). Recently we demonstrated that B/F recombinant forms are prevalent among heterosexual men and women. HMA analysis was completed for a group of 35 MSM and 175 HMW. In MSM genotype B was found in 91.4% (32/35) and genotype F in 8.6% (3/35) while in HMW genotype B was found in 23.4% (4/175) and genotype F in 74.6% (134/175) p<0.0000000). Partial and complete genome sequencing of samples from these groups determined that B/F recombinant forms were detected in all 12 subtype F isolates and in 4 of 6 subtype B isolates studied up to date. Among them, a new circulating recombinant form (CRF12_BF) was described. Objectives: The current study was designed and carried out aiming to comparing previous data obtained in our laboratory in 96 HIV+  MSM and 175 HIV+  HMW with recent IDU data. Methods: 77 HIV+ IDUs were included in the study during 2001. Informed consent and questionnaires regarding drug and sexual practices were administred and then completed. Peripheral blood mononuclear cells (PBMC) were used for genotyping. DNA sequences were obtained on a subset of 21 randomly selected samples by partial sequencing in gag, pol and vpu genes. In order to determine established or recent infection, “detuned assay” (STARHS) was utilized in all positive sera. Results: In the injecting-drug population, 100% of the 21 samples resulted BF recombinants in at least one of the three studied genes. The analysis of the mosaic structure of the genomes revealed that 12 samples (57%) showed the same pattern as CRF12_BF,  whereas, in the others, the pattern differed in at least one of the three genes. Detuned assay depicted that no recent infections were detected in any of the samples. Conclusions: HIV molecular epidemiology showed a relationship between HIV subtype and the route of transmission. A high prevalence of BF recombinants was detected among HMW and IDU and a predominance of subtype B among MSM. Confirmation by sequencing studies is still to be done among the latter. In IDU 100% of the samples studied presented recombinants with similar pattern to CRF12_BF in one or more genes. This along with the lack of evidence of new infections among IDU suggest that BF recombinants in Argentina might have originated in the injecting-drug population, thus acting as the vehicle of dissemination on to the heterosexual population.