Immune reconstitution to cytomegalovirus following partially matched-related donor transplantation: impact of in vivo T-cell depletion and granulocyte colony-stimulating factor-primed peripheral blood/bone marrow mixed grafts

Cytomegalovirus (CMV) infection and delayed immune reconstitution remains a serious obstacle for successful partially matched-related donor transplantation (PMRD). We evaluated 42 patients for the development of CMV-specific CD8+ T lymphocytes (CTLCMV) following granulocyte colony-stimulating factor-primed peripheral blood (PB) and bone marrow (BM) with anti-thymocyte globulin (ATG)-based PMRD. PMRD recipients achieved a high frequency, proliferation capacity, and interferon-gamma response of CTLCMV at 1 year post transplantation. CTLCMV with the central memory CD45RO+CD62L+ cell phenotype expanded in PB and BM-resident CTLCMV displayed distinct phenotypes when CMV was reactivated. Although the incidence of CMV reactivation was high in PMRD patients (87.67%), only 11.90% of them developed CMV disease. In conclusion, after PMRD using mixed grafts with ATG-based conditioning, immune recovery to CMV seems to be early and fast, thereby reducing the incidence of CMV disease.