Reconstitution of naive T cells during antiretroviral treatment of HIV-infected adults is dependent on age

OBJECTIVE: To determine the influence of age on the regeneration rate of naive and memory T cells in the blood of 45 adults on highly active antiretroviral therapy (HAART). METHODS: The age of the patients ranged from 25 to 57 years. Naive cells were defined as CD45RA+CD27+. Cells negative for CD45RA and/or CD27 were considered memory type cells. RESULTS: The recovery rates of naive CD4 and CD8 T cells were similar, were negatively correlated with age and were decreasing 5% and 3.6% per year, respectively. In a multivariate regression analysis, only age was significantly correlated with the naive T cell recovery rates. The recovery rate of memory T cells showed no relation to age. The average regeneration rate of naive CD4 T cells during HAART, i.e., 0.34 x 10(6) cells/l per day, is not lower than regeneration rates in HIV-negative adults following cytotoxic chemotherapy or CD4 monoclonal antibody therapy. CONCLUSION: These observations suggest that the thymus contributes considerably to the regeneration of naive T cells in adults on HAART, and that the impact of HIV infection on naive T cell production is small, or rapidly reversible.