The results of our work demonstrate that the number of HIV-1 variants using CXCR4 coreceptor also increases with the duration of the disease among the studied subtype A viruses isolated from the patients with confirmed date of infection: the CXCR4-tropic viruses were isolated from 13.6% of the subjects infected several months to 3 years ago and 25% of the subjects infected over 5 years ago, which agrees with the data of other researchers. The gene discussed is CXCR4; the disease is infection.