Baseline thymic volume is a predictor for CD4 T cell repopulation in adult HIV-infected patients under highly active antiretroviral therapy.

The objective of the present study was to assess the impact of baseline thymic volume on the CD4 cell repopulation induced by highly active antiretroviral therapy (HAART) in HIV-infected adults. Therefore, 37 previously untreated HIV-1-infected adults were prospectively followed from August 1998 to September 2001. All patients underwent a thorax CT scan at starting HAART to measure thymic volume. The median follow-up time was 189 [87.5-498.5] days. CD4 cell repopulation was considered as an increase > or = 200 cells/mm3 above baseline count. Twenty-one (57%) patients achieved this CD4 repopulation. Baseline thymic volume was the main independent factor associated with CD4 repopulation (P = 0.016); this factor was a positive predictor (adjusted hazard ratio: 1.25 [95% confidence interval 1.1-1.4]). Although, CD4 cell count and non-AIDS diagnosis at baseline were associated with CD4 cell repopulation on the univariate analysis (P = 0.03 and P = 0.02, respectively), no statistical signification was found on the multivariate test. In summary, baseline thymic volume is a predictor of early CD4 cell repopulation in adult HIV-1-infected patients taking HAART.