Increased cell division but not thymic dysfunction rapidly affects the T-cell receptor excision circle content of the naive T cell population in HIV-1 infection

Nat Med. 2000 Sep;6(9):1036-42. doi: 10.1038/79549.


Recent thymic emigrants can be identified by T cell receptor excision circles (TRECs) formed during T-cell receptor rearrangement. Decreasing numbers of TRECs have been observed with aging and in human immunodeficiency virus (HIV)-1 infected individuals, suggesting thymic impairment. Here, we show that in healthy individuals, declining thymic output will affect the TREC content only when accompanied by naive T-cell division. The rapid decline in TRECs observed during HIV-1 infection and the increase following HAART are better explained not by thymic impairment, but by changes in peripheral T-cell division rates. Our data indicate that TREC content in healthy individuals is only indirectly related to thymic output, and in HIV-1 infection is mainly affected by immune activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-HIV Agents / therapeutic use
  • Cell Division
  • Gene Rearrangement, T-Lymphocyte
  • HIV Infections / drug therapy
  • HIV Infections / immunology*
  • HIV-1 / immunology*
  • Humans
  • Receptors, Antigen, T-Cell / genetics*
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • Thymus Gland / immunology*


  • Anti-HIV Agents
  • Receptors, Antigen, T-Cell