Immunological Rebound after Initiation of Highly Active Antiretroviral Therapy in Treatment-Naive Patients

Abstract

Large clinical trials have repeatedly proven the effectiveness of highly active antiretroviral therapy (HAART) in achieving virological suppression; however, subsequent increases in CD4 cell counts (i.e., immunological rebound) do not always follow. Thus, it remains unclear to what extent persons living with HIV/AIDS may expect significant increases in CD4 cell count upon HAART initiation, particularly outside of the highly structured environment of a clinical trial. We analyzed the patterns of CD4 and plasma viral load (PVL) change in 170 HIV-infected individuals who were ART naive and initiated HAART between 1997 and 2003. Immunological success (>50 CD4 cells/mm(3) increase) was evaluated using Kaplan-Meier survival analysis and Cox proportional hazard models. Of individuals, 80% experienced a confirmed CD4 cell count increase of >50 cells/mm(3) after HAART initiation. Multivariate analysis showed that patients with pre-HAART PVL >or=100,000 copies/ml were more likely to achieve immunological success when compared with patients with baseline PVL <10,000 copies/ml, suggesting that individuals with the highest HIV viral load levels may benefit the most from HAART initiation. Future studies of immunological rebound are warranted to further define and characterize immune responses to HAART in diverse populations in order to optimize guidelines for initiation of treatment and assessment of successful responses.