T cell receptor excision circles and HIV-1 2-LTR episomal DNA to predict AIDS in patients not receiving effective therapy

Objective: To determine whether improved prediction of AIDS-free survival following HIV-1 seroconversion is achieved by measuring HIV-1 2-LTR episomal DNA (2-LTR) circles and T cell receptor rearrangement excision circles (TREC), reflecting HIV replication and lymphocyte emigration from the thymus, respectively. Design: Subanalysis of a cohort of 154 patients with hemophilia who became HIV positive between 1978 and 1985 and were followed prospectively. Methods: Relative hazards (RH) of AIDS, in the absence of highly effective anti-HIV therapy, were estimated for age, HIV-1 viral load, CD4 lymphocyte count and levels of HIV-1 2-LTR circles and TREC [per 10(6) peripheral blood mononuclear cells (PBMC)] Results: TREC correlated significantly with CD4 cell counts (r = 0.30) and age (r = -0.60). 2-LTR circles correlated significantly with HIV-1 viral load (r = 0.35). If viral load, CD4 lymphocytes and age were included in a proportional hazards model, the risk of AIDS during a median of 11.6 years of follow-up was increased significantly with fewer TREC (adjusted RH, 2.0 per log(10) copies/10(6) PBMC) and more 2-LTR circles (RH, 1.7 per log(10) copies/10(6) PBMC). AIDS prediction with TREC and 2-LTR circles held for most subgroups defined by median viral load, CD4 lymphocytes and age. Conclusions: PBMC that have high levels of HIV-1 replication and low levels of recent thymic emigrants are associated with a substantially increased risk of AIDS. It is not known if measurement of either TREC or 2-LTR circles will complement HIV-11 viral load as an estimation of the risk of AIDS for patients who are receiving highly effective anti-HIV therapy. (C) 2001 Lippincott Williams Wilkins.