Impaired dendritic cell immunophenotype and function in heart transplant patients undergoing active cytomegalovirus infection

Human cytomegalovirus (HCMV) infects dendritic cells (DCs) in vitro and inhibits their maturation properties and their ability to stimulate T-cell proliferation and cytotoxicity. This study analyzed HCMV infection of DCs in vivo. We compared blood DCs and monocyte-derived DCs from heart-transplant patients undergoing an acute HCMV infection with DCs obtained from HCMV-negative transplant patients. Diagnosis of active HCMV infection was established by antigenemia test. We detected viral RNA and antigens in defined DC subsets obtained from patients undergoing an active HCMV infection. In addition, we found an impaired immunophenotype in immature DCs from HCMV-positive subjects and a reduced ability of mature DCs from the same group of patients to stimulate allogenic T-cell proliferation. The impaired immunophenotype and function detected in DCs from transplant patients undergoing an active HCMV infection may be a mechanism used by the virus to interfere with early immune functions and thereby contributing to the HCMV-induced immunosuppression in these patients.