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Keywords:

  • CD4+ T lymphocytes;
  • intraepithelial lymphocytes;
  • CD103;
  • flow cytometry

Abstract

Background

The integrin CD103 is preferentially expressed on intraepithelial T lymphocytes, and cells expressing this integrin may play a regulatory role in the microenvironment of the epithelial cell layer.

Methods

The relative number of CD103+/CD4+ T cells in the bronchoalveolar lavage was significantly elevated in all patients diagnosed with interstitial lung diseases compared with patients with other non-fibrotic disorders of the lung.

Results

Analysis by flow cytometry showed that the CD103+ and the CD103 subpopulations were memory T cells based on the high expression of CD45RO+. However, the CD103+/CD4+ T cells were CD25low, CD27, CD28low, and CD62L, whereas the CD103/CD4+ T cells expressed CD25 and CD62L and were CD27high and CD28high. In addition, the CD103+/CD4+ T cells expressed significantly higher quantities of VLA-1 and CD101 than did CD103/CD4+ T cells. Reverse transcriptase polymerase chain reaction analysis of purified CD103+ and CD103 CD4+ T cells showed production of tumor necrosis factor (TNF) α-R-1 (p55), TNF-α-R-2 (p75), interferon γ, interleukin-10, and TNF-α mRNA in both subpopulations. No interleukin-4 mRNA was detected in either subpopulation.

Conclusions

CD103+/CD4+ T cells represent a T-helper 1–like subpopulation in human lungs with a distinct effector phenotype. Despite the lack of CD27 and the low CD25 and CD28 expression, these cells show a high degree of activation. These results suggest that CD103 expressing CD4 T cells in the lung are continuously activated, long-living cells. Cytometry Part B (Clin. Cytometry) 54B:19–27, 2003. © 2003 Wiley-Liss, Inc.