Major expansion of (gamma delta) T lymphocytes following cytomegalovirus infection in kidney allograft recipients

In normal persons, circulating gammadelta T cells comprise a minor cell subset (0.5%-6% of total lymphocytes). gammadelta T cells were studied in the context of therapeutic immunosuppression in transplanted patients. Flow cytometry detected an expansion of gammadelta T cells in 31 of 205 renal allograft recipients and in 2 of 41 uremic patients but in none of 45 healthy subjects. Univariate statistical analysis identified cytomegalovirus (CMV) infection (P6% gammadelta T cells. gammadelta T cell expansion directly followed CMV infection and was never observed in persons who did not develop CMV infection. Thus gammadelta T cells may represent a first-line defense mechanism against CMV infection in a person whose alphabeta T cell response has been weakened by immunosuppression.