BACKGROUND: Measures to prevent transfusion-transmitted cytomegalovirus (TT-CMV) infection after hematopoietic stem cell transplantation (HSCT) include transfusion of CMV antibody–negative blood units and/or transfusion of leukoreduced cellular blood products. We assessed the incidence of TT-CMV in CMV-seronegative patients receiving CMV-seronegative HSC transplants, who were transfused with leukoreduced cellular blood products not tested for anti-CMV.

STUDY DESIGN AND METHODS: In a prospective observational study between 1999 and 2009, all HSCT patients received leukoreduced cellular blood products not tested for anti-CMV. Patients were screened for CMV serostatus and CMV-negative recipients of CMV-negative transplants were systematically monitored for TT-CMV clinically and by CMV nucleic acid testing. Anti-CMV antibodies (immunoglobulin [Ig]G and IgM) were assessed after three time intervals (Interval 1, study inclusion to Day +30 after HSCT; Interval 2, Day +30-Day +100; Interval 3, after Day +100).

RESULTS: Among 142 patients treated with allogeneic HSCT, 23 CMV-negative donor-patient pairs were identified. These 23 patients received 1847 blood products from 3180 donors. All patients remained negative for CMV DNA and none developed CMV-associated clinical complications. This results in a risk for TT-CMV per donor exposure of 0% (95% confidence interval, 0.0%-0.12%). However, 17 of 23 patients seroconverted for anti-CMV IgG, but none for anti-CMV IgM. CMV IgG seroconverters received significantly more transfusions per week than nonconverters.

CONCLUSION: The risk of TT-CMV is low in high-risk CMVneg/neg HSCT patients transfused with leukoreduced blood products not tested for anti-CMV. The cause of anti-CMV IgG seroconversion is most likely passive antibody transmission by blood products.