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 (CTL(CMV) ) 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-γ response of CTL(CMV) at 1 year post transplantation. CTL(CMV) with the central memory CD45RO+CD62L+ cell phenotype expanded in PB and BM-resident CTL(CMV) 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.