The vast majority of CLA+ T cells are resident in normal skin

J Immunol. 2006 Apr 1;176(7):4431-9. doi: 10.4049/jimmunol.176.7.4431.


There are T cells within normal, noninflamed skin that most likely conduct immunosurveillance and are implicated in the development of psoriasis. We isolated T cells from normal human skin using both established and novel methods. Skin resident T cells expressed high levels of CLA, CCR4, and CCR6, and a subset expressed CCR8 and CXCR6. Skin T cells had a remarkably diverse TCR repertoire and were mostly Th1 memory effector cells with smaller subsets of central memory, Th2, and functional T regulatory cells. We isolated a surprising number of nonexpanded T cells from normal skin. To validate this finding, we counted T cells in sections of normal skin and determined that there are approximately 1 x 10(6) T cells/cm(2) normal skin and an estimated 2 x 10(10) T cells in the entire skin surface, nearly twice the number of T cells in the circulation. Moreover, we estimate that 98% of CLA(+) effector memory T cells are resident in normal skin under resting conditions. These findings demonstrate that there is a large pool of memory T cells in normal skin that can initiate and perpetuate immune reactions in the absence of T cell recruitment from the blood.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Neoplasm
  • Cell Movement
  • Cell Separation / methods
  • Cells, Cultured
  • E-Selectin / metabolism
  • Gene Expression Regulation
  • Humans
  • Immunologic Memory
  • Membrane Glycoproteins / metabolism*
  • Phenotype
  • Protein Binding
  • Receptors, Antigen, T-Cell / metabolism
  • Skin / cytology
  • Skin / immunology
  • Skin / metabolism*
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*


  • Antigens, Differentiation, T-Lymphocyte
  • Antigens, Neoplasm
  • CTAGE1 protein, human
  • E-Selectin
  • Membrane Glycoproteins
  • Receptors, Antigen, T-Cell