Gamma delta T-cell receptor-positive cells in human skin. I. Incidence and V-region gene expression in granulomatous skin lesions.

BACKGROUND: There have been many reports that gamma delta T-cell receptor (TCR)+ cells respond to mycobacterial antigens in vitro, but there is little available information on human gamma delta TCR+ cells in clinical conditions.
OBJECTIVE: Our purpose was to investigate the distribution and involvement of human gamma delta TCR+ cells in granulomatous skin lesions.
METHODS: The incidence and V-region gene expression of human gamma delta TCR+ cells was examined in granulomatous skin diseases, including cutaneous tuberculosis and leprosy, by immunohistochemical procedures.
RESULTS: gamma delta TCR+ cells in the dermis were increased in most patients with borderline lepromatous leprosy, and they were less frequently found in lepromatous leprosy and erythema nodosum leprosum. Other granulomatous skin lesions, including sarcoidosis, contained only a few gamma delta TCR+ cells. The gamma delta TCR+ cells that were found to be increased in this study were mostly delta TCS1-, BB3+, Ti gamma A+ (V delta 1-, V delta 2+, V gamma 9+).
CONCLUSION: The gamma delta TCR+ cells in human granulomatous skin lesions may respond to some mycobacterial antigens, but they do not appear to be directly involved in granuloma formation.