Cutting edge: The prevalence of regulatory T cells lymphoid tissue is correlated with viral load HIV-infected patients

Inadequate local cell-mediated immunity appears crucial for the establishment of chronic HIV infection. Accumulation of regulatory T cells (T-reg) at the site of HIV replication, the lymphoid organs, may influence the outcome of HIV infection. Our data provide the first evidence that chronic HIV infection changes T-reg tissue distribution. Several molecules characteristics of T-reg (FoxP3, CTLA-4, glucocorticoid-induced TNFR family-related receptor, and CD25) were expressed more in tonsils of untreated patients compared with antiretroviral-treated patients. Importantly, most FoxP3(+) cells expressed CTLA-4, but not CD69. Furthermore, a direct correlation between FoxP3 Levels and viral load was evident. In contrast, FoxP3 expression was decreased in circulating T cells from untreated patients, but normalized after initiation of treatment. Functional markers of T-reg activity (indoleamine 2,3-dioxygenase, TGF-beta, and CD80) were markedly increased in the tonsils of untreated patients. Our data could provide a new basis for immune-based therapies that counteract in vivo T-reg and thereby reinforce appropriate antiviral immunity.