Sexually transmitted infections, sexual risk behaviors and the risk of heterosexual spread of HIV among and beyond IDUs in St. Petersburg, Russia.

AIMS: This study investigates whether sexual transmitted behaviors and infections (STIs) among injection drug users (IDUs) may promote the spread of HIV among and beyond IDUs in Russia. METHODS: We conducted a cross-sectional survey of behavior and tested for STIs in a convenience sample of 159 IDUs in St. Petersburg, Russia. RESULTS: The median age was 27 and 57% were male. Almost all were sexually active, half had casual partners and 40% reported > or =2 sex partners in the previous 3 months. Of those who answered, 81% reported sex without condoms, 44% reported having sex with at least one partner who was not an IDU. Of 139 (87%) subjects who were actively injecting, 29% reported receptive syringe sharing. Twenty percent of subjects were seropositive for HIV-1 and 42% of HIV-1-negative subjects tested positive for an STI. CONCLUSIONS: The sample exhibited high levels of sexual risk behaviors and STIs, and a large proportion had sexual partners who were not IDUs. This population requires comprehensive interventions that ensures access to condoms and sterile injection supplies and that encourage safer sexual behaviors in an attempt to keep sexual transmission of HIV low.

Host-dependent serum specificity to the V3 domain of HIV-1.

The previous studies of anti-HIV-1 humoral immune response have found the stable individual structural bias in the antibody production that reflects the changes in the immune functional network caused by HIV-1. The correlation between antigen structure, in particular the V3 domain of HIV-1, and the serum specificity to the structure remains unclear. To clarify the role of host individual factors in the serum specificity, we used the slightly modified HIV-1 serotyping methodological approach for the sera of the patients infected with HIV-1 with a different level of genetic similarity. Substantial discrepancy between serum specificities and antigen structure was found. Patients infected with HIV-1 carrying similar and identical V3 sequences had significantly different serum specificities. The opposite situation was often observed as well. The results of the study suggest that the influence of the V3 loop structure in the development of humoral immune response to the V3 loop is substantially modified in a patient-specific manner.