T cell receptor excision circle (TREC) content following maximum HIV suppression is equivalent in HIV-infected and HIV-uninfected individuals

Carolyn M. Steffens, Kimberly Y. Smith, Alan Landay, Susan Shott, Allison Truckenbrod, Mary Russert, Lena Al-Harthi

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Background: The adult human thymus contributes to de novo T cell synthesis; such synthesis can be assessed by analyzing T cell receptor excision circles (TREC). Methods: TREC levels were measured in total peripheral blood mononuclear cells (PBMC) and CD4- and CD8-enriched cells of 29 HIV-positive patients with maximal viral suppression. The expression of CD45RA+CD45RO-, CD45RA+CD62L+, CD45RO-CD27+CD95low and HLA-DR+CD38+ was assessed using three-color flow cytometric analysis of whole blood. Thymic index score was based on computed tomographic scans of the thymus. The relationship of TREC with thymic index and the expression of the naive phenotypes was evaluated. Results: TREC expression was not statistically different in these HIV-positive patients from that in age-matched HIV-negative controls. Among HIV-positive patients with CD4 cell count of >500× 106 cells/I after antiretroviral therapy (n = 15), PBMC TREC levels correlated with the expression of CD45RA+CD45RO- and CD45RA+CD62L+ naive phenotypes, and inversely correlated with the expression of HLA-DR+CD38+. The change between pre- and post-therapy CD4 cell counts for these 15 patients significantly correlated with both thymic index and expression of the CD45RA+CD45RO- phenotype. Conclusions: The finding that TREC expression was equivalent between HIV-positive patients after therapy and HIV-negative donors suggests that there is no reduction in thymic output among HIV-positive individuals after therapy. Given that TREC is inversely correlated with HLA-DR/CD38 expression, its analysis in studies of thymopoiesis should be evaluated in the context of maximum viral suppression to reduce HIV-mediated immune activation and/or by normalizing for cell turnover.

Original languageEnglish (US)
Pages (from-to)1757-1764
Number of pages8
Issue number14
StatePublished - Sep 28 2001
Externally publishedYes


  • Antiroviral therapy
  • HIV
  • Naive markers
  • T cell receptor excision circle
  • Thymic index
  • Thymic output
  • TREC

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Infectious Diseases


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