Role of gamma delta T lymphocytes in the development of Behcet's disease

Phenotypic and functional properties of gamma delta T cells, which play an important role in mucocutaneous immunity, were examined to elucidate whether immunological abnormality in Behcet's disease may be related to a specific T cell population. We found that CD45RA(+)V gamma 9(+)V delta 2(+) gamma delta T cells, which constitute a minor population of ya T cells in healthy individuals, were increased in number in Behcet's disease irrespective of disease activity. This CD45RA(+) subset of gamma delta T cells in the active, but not inactive, phase of this disease expressed IL-2R beta and HLA-DR, suggesting that they are activated in vivo in active Behcet's disease. In addition, the CD45RA(+) gamma delta T cells produced extreme amounts of tumour necrosis factor and contained perforin granules. These data indicate that a phenotypically distinct subset of gamma delta T cells, CD45RA(+)CD45RO(-)V gamma 9(+)V delta 2(+), may contribute to immunological abnormalities which may lead to complexity of pathophysiology in Behcet's disease.