HIV-1 genotyping tropism profile in an HIV-positive population throughout the Russian Federation

Most HIV-1 tropism studies have involved non-A subtypes. Our aim was to study the prevalence of R5- and non-R5-tropic HIV-1 variants and the tropism occurrence relative to the CD4 counts, treatment experiences, transmission routes and other features of infection in Russia, where subtype A is presumably predominant. In this multicenter, single-step, cross-sectional, epidemiologic study, 943 HIV-1-infected patients were enrolled at 12 AIDS centers throughout Russia. Viral tropism was determined using a genotype method-based kit. The V3 loop sequences were analyzed using the geno2pheno resource. The tropism was successfully predicted for 823 (87.3%) patients. Frequencies of R5-tropic and non-R5-tropic viruses in successfully analyzed samples were 70.2% (578) and 29.8% (245), respectively. Co-receptor usage correlated significantly only with the treatment experiences (p = 0.018) and CD4 counts (p = 0.004). But there was no dependence of R5/non-R5 co-receptor usage frequencies on presence/absence of a therapy change (p = 0.664) or HIV infection duration (p = 0.458). According to the env sequences, 457 (83.6%) of the samples in study were subtype A and 70 (12.8%) were subtype B. This indicates a stabilizing of immune system and thus little emergence of X4 viruses. We suggest that CCR5-antagonists could be used in both naïve and experienced patients in Russia after determination of HIV tropism.