Cytomegalovirus infection in transplant recipients resolves when circulating gamma delta T lymphocytes expand, suggesting a protective antiviral role

gamma delta T cells undergo massive expansion in the peripheral blood of re nal transplant recipients who are infected with cytomegalovirus (CMV). In a 3-year prospective study, the relationship between the evolution of CMV in fection and the kinetics of gamma delta T cell amplification was followed f or 10 months after transplantation. Patients with late gamma delta T cell e xpansion (greater than or equal to 45 days) had significantly longer (P < . 0001) and higher (P < .0003) pp65 antigenemia and more-symptomatic CMV dise ase than did patients with early expansion. Analysis of data for each patie nt showed that gamma delta T cell expansion is concomitant with the resolut ion of CMV infection and disease, regardless of the CMV serologic status of donor and recipient before transplantation. These observations point to ga mma delta T cell percentage determination as a new, rapid, and reliable pro gnosis factor to predict the resolution of CMV infection and strongly sugge st that gamma delta T cells play a protective role against CMV infection.