Thymic output during initial highly active antiretroviral therapy (HAART) and during HAART supplementation with interleukin 2 and/or with HIV type 1 immunogen (Remune)

The thymic output of patients receiving highly active antiretroviral therapy (HAART) was assessed by sjTREC (signal joint T cell receptor rearrangement excision circle) analysis to determine the thymic contribution to CD4⁺ T cell reconstitution during initial therapy and during interleukin 2 (IL-2) and/or Remune supplementation of HAART. Levels of sjTRECs were observed to decline dramatically after the first 4 weeks of HAART and then increased without significant associated changes in CD4⁺ T cell counts. HAART supplementation with IL-2 was observed to lead to rapid increases in CD4⁺ T cells that were accompanied by sjTREC decreases. No notable changes in CD4⁺ T cell counts and sjTRECs were seen in patients receiving HAART supplemented with Remune alone. The results indicate CD4⁺ T cell maintenance during initial treatment of HIV-1 with HAART and early CD4⁺ T cell reconstitution of patients receiving IL-2 with HAART is largely due to thymus-independent mechanisms, with the thymus making a limited contribution.