Correlating HIV tropism with immunological response under combination antiretroviral therapy

Objectives A significant percentage of patients infected with HIV ‐1 experience only suboptimal CD 4 cell recovery while treated with combination therapy ( cART ). It is still unclear whether viral properties such as cell tropism play a major role in this incomplete immune response. This study therefore intended to follow the tropism evolution of the HIV ‐1 envelope during periods of suppressive cART . Methods Viruses from two distinct patient groups, one with good and another one with poor CD 4 recovery after 5 years of suppressive cART , were genotypically analysed for viral tropism at baseline and at the end of the study period. Results Patients with CCR 5‐tropic CC‐motif chemokine receptor 5 viruses at baseline tended to maintain this tropism to the study end. Patients who had a CXCR 4‐tropic CXC‐motif chemokine receptor 4 virus at baseline were overrepresented in the poor CD 4 recovery group. Overall, however, the majority of patients presented with CCR 5‐tropic viruses at follow‐up. Conclusions Our data lend support to the hypothesis that tropism determination can be used as a parameter for disease progression even if analysed long before the establishment of a poorer immune response. Moreover, the lasting predominating CCR 5‐tropism during periods of full viral control suggests the involvement of cellular mechanisms that preferentially reduce CXCR 4‐tropic viruses during cART .