Monitoring of Human Cytomegalovirus‐Specific CD4+ and CD8+ T‐Cell Immunity in Patients Receiving Solid Organ Transplantation

Absolute and human cytomegalovirus (HCMV)‐specific CD4+ and CD8+ T‐cell counts were monitored in 38 solid organ (20 heart, 9 lung and 9 kidney) transplant recipients during the first year after transplantation by a novel assay based on T‐cell stimulation with HCMV‐infected autologous dendritic cells. According to the pattern of T‐cell restoration occurring either within the first month after transplantation or later, patients were classified as either early (n = 21) or late responders (n = 17). HCMV‐specific CD4+ and CD8+ T‐cell counts were consistently lower in late compared to early responders from baseline through 6 months after transplantation. In addition, in late responders, while HCMV infection preceded immune restoration, HCMV‐specific CD4+ restoration was significantly delayed with respect to CD8+ T‐cell restoration. The number of HCMV‐specific CD4+ and CD8+ T‐cells detected prior to transplantation significantly correlated with time to T‐cell immunity restoration, in that higher HCMV‐specific T‐cell counts predicted earlier immune restoration. Clinically, the great majority of early responders (18/21, 85.7%) underwent self‐resolving HCMV infections (p = 0.004), whereas the great majority of late responders (13/17, 76.5%) were affected by HCMV infections requiring antiviral treatment (p =