Increased peripheral expansion of naive CD4+ T cells in vivo after IL-2 treatment of patients with HIV infection

摘要

Intermittent interleukin-2 (IL-2) therapy has been shown to in- crease the number of CD4+ T cells, preferentially cells with a naive phenotype, in patients with HIV infection. For this report we investigated the mechanism underlying this expansion by studying the relative roles of peripheral expansion and thymic output. In a cohort of six patients receiving IL-2 over a period of 1 year, the mean number of naive CD4+ T cells increased from 139 to 387 cells per μl while levels of T cell receptor rearrangement excision circles (TRECs) declined from 47,946 to 26,510 copies per 10~6 naive T cells, thus making it unlikely that the CD4+ T cell count increases were secondary to increase in thymic output.