Donor cytomegalovirus seropositivity and the risk of leukemic relapse after reduced-intensity transplants

Objectives: Despite effective preemptive and prophylactic therapeutic strategies, cytomegalovirus (CMV) seropositivity of either recipient and/or donor still remains an important parameter for outcome even after reduced-intensity allogeneic stem cell transplantation (SCT). Whether CMV seropositivity of the donor might have an impact on leukemic relapse is unknown. Patients: Between June 1999 and February 2004 48 patients ineligible for conventional allotransplantation underwent reduced-intensity transplants at our institution. Twenty-seven (56%) patients had a CMV-seropositive donor. Results: While donor CMV seropositivity had no effect on overall survival, having a CMV-seropositive donor was associated with a significantly lower risk for relapse (20% vs. 52%, P = 0.02). The beneficial effect of a CMV-seropositive donor, however, was offset by a higher transplant-related mortality (42% vs. 19% in patients with a CMV-seronegative donor, P = 0.2). Donor CMV serostatus had no effect on the incidence of CMV infection/disease, and acute or chronic graft-vs.-host disease. Overall, 27 patients died during the observation period. Causes of death in patients with a CMV-seropositive donor were primarily transplant-related (11 vs. 4 in patients with CMV-seronegative donors), whereas leukemic relapse was the leading cause of death in patients with a CMV-seronegative donor (8 vs. 4 in patients with a CMV-seropositive donor, P = 0.038, chi-squared test). Multivariate Cox regression analysis showed risk category by the underlying disease and donor CMV seropositivity to be significant predictors of leukemic relapse following reduced-intensity transplants. Conclusions: These preliminary results suggest a possible role of donor CMV serostatus on the risk of relapse following reduced-intensity allogeneic SCT.