IL-7Ralpha expression on CD4+ T lymphocytes decreases with HIV disease progression and inversely correlates with immune activation

Eur J Immunol. 2006 Feb;36(2):336-44. doi: 10.1002/eji.200535111.

Abstract

Many factors can influence the rate of HIV disease progression, including those that maintain T cell homeostasis. One key homeostatic regulator is the IL-7 receptor (IL-7R). Previous studies have shown IL-7R expression levels decrease in HIV infection, but effects on memory subtypes, CD4(+) T cells, and cell function have not been explored. The present study examined the expression of the IL-7Ralpha chain on naïve and memory T lymphocyte subsets of both HIV-positive and HIV-negative individuals from Nairobi, Kenya to assess the role of IL-7Ralpha in HIV disease. Expression of IL-7Ralpha was significantly reduced in all CD4(+) and CD8(+) T cell subsets in HIV-positive individuals. This reduction was further enhanced in those with advanced HIV progression. Expression of IL-7Ralpha was inversely correlated to immune activation, and apoptosis, and was positively correlated with CD4 count in both bivariate and multivariate analysis. Expression of IL-7Ralpha did not correlate with HIV viral loads, indicating the elevated immune activation seen in HIV-infected individuals may be impacting expression of IL-7Ralpha, independent of viral loads. Signaling via the IL-7R is essential for T cell homeostasis and maintenance of T cell memory. Reduction of this receptor may contribute to the homeostatic disruption seen in HIV.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / immunology
  • CD4 Lymphocyte Count
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / pathology
  • CD4-Positive T-Lymphocytes / virology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / pathology
  • CD8-Positive T-Lymphocytes / virology
  • Disease Progression
  • Gene Expression Regulation / immunology*
  • HIV Seropositivity / immunology*
  • HIV Seropositivity / pathology
  • HIV Seropositivity / virology
  • Humans
  • Immunologic Memory / immunology
  • Lymphocyte Activation
  • Male
  • Receptors, Interleukin-7 / immunology*
  • Signal Transduction / immunology
  • Viral Load

Substances

  • Receptors, Interleukin-7
  • interleukin-7 receptor, alpha chain