Effect of recent thymic emigrants on progression of HIV-1 disease

The concentration of T-cell receptor-rearrangement excision DNA circles (TREC) in peripheral-blood T cells is a marker of recent thymic emigrant αβ T cells. We studied the predictive ability of measurements of TREC for clinical outcome in HIV-1-infected individuals. We measured TREC in peripheral-blood mononuclear cells with a real-time PCR assay. We studied 131 Greek participants in the Multicenter Hemophilia Cohort Study who had known HIV-1 seroconversion dates. The prognostic value of baseline TREC, CD4 T-cell count, and HIV-1 RNA concentration was assessed by Kaplan-Meier and Cox's regression analysis. Four participants had progressed to AIDS by first blood sampling. Among the remaining 127 individuals, the median value of TREC per 10 6 cells was 6900 (IQR 2370–15 604). Baseline TREC values were lower in the 53 who progressed to AIDS than in those who did not (geometric mean 2843 [95% CI 1468–5504] vs 6560 [4723–9113] per 10 6 cells; p=0·017). The relative hazard of AIDS, adjusted for plasma viral load, CD4 T-cell count, and age at seroconversion was 1·44 (95% CI 1·04–2·01; p=0·031) per ten-fold increase in TREC; that for death was 1·52 (1·12-2·06; p=0·007). The adjusted relative hazards of death were 2·91 (1·91–4·44; p