HIV-2 viral tropism influences CD4+ T cell count regardless of viral load

Abstract

Background:HIV-2 infection is characterized by low plasma viraemia and slower progression to AIDS in compari-son with HIV-1 infection. However, antiretroviral therapy in patients with HIV-2 is less effective and often fails toprovide optimal CD4 recovery.Methods:We examined viral tropism in persons with HIV-2 infection enrolled in the HIV-2 Spanish cohort. Viraltropism was estimated based on V3 sequences obtained from plasma RNA and/or proviral DNA.Results:From a total of 279 individuals with HIV-2 infection recorded in the Spanish national register, 58 V3sequences belonging to 42 individuals were evaluated. X4 viruses were recognized in 14 patients (33%).Patients with X4 viruses had lower median CD4+cell counts than patients with R5 viruses [130 (17 – 210) versus359 (180 – 470) cells/mm3;P¼0.007]. This was true even considering only the subset of 19 patients on antiretro-viral therapy [94 (16 – 147) versus 184 (43 – 368) cells/mm3;P¼0.041]. In multivariate analysis, significant differ-ences in CD4+cell counts between patients with X4 and R5 viruses remained after adjusting for age, gender,antiretroviral therapy and viral load.Conclusions:The presence of X4-tropic viruses in HIV-2 infection is associated with low CD4+cell counts, regard-less of antiretroviral treatment. Along with CD4+cell counts, viral tropism testing may assist decisions aboutwhen to initiate antiretroviral therapy in HIV-2-infected individuals.