Common Features of γδ T Cells and CD8+ αβ T Cells Responding to Human Cytomegalovirus Infection in Kidney Transplant Recipients

Background. Kidney transplant recipients infected with cytomegalovirus (CMV) undergo a persistent gamma delta T cell expansion in their peripheral blood. The anti-CMV function of these cells was previously demonstrated by their ability to kill CMV-infected cells in vitro. Methods. To gain insight into the role of gamma delta T cells within the antiviral immune network, we compared the expansion kinetics of these T cells with that of CMV pp65-specific CD8(+) alpha beta T cells in the peripheral blood of twenty-one kidney transplant recipients. Results. Both the percentage and the absolute number of pp65-specific CD8(+) T cells and gamma delta T cells showed a concomitant increase and persistence in most of the kidney transplant recipients with CMV infection. Both cell subsets exhibited an effector/memory phenotype (CD28(-), CD27(-), and CD45RA(+)) that predominated for the entire follow-up period. Conclusions. In conclusion, CMV-specific CD8+ alpha beta T cells and gamma delta T cells share common expansion kinetics and a common effector phenotype, suggesting that these cell types act similarly in response to CMV infection.