Transfusion-associated cytomegalovirus infections in seropositive cardiac surgery patients

To determine whether reinfection with an exogenous strain of cytomegalovirus (CMV) or reactivation of endogenous CMV is responsible for post-transfusion CMV infections in patients previously infected with the virus, seropositive patients were randomised preoperatively to receive red blood-cells (RBCs) from CMV seronegative donors (group A) or from random donors (group B). Each group B patient received at least one seropositive unit. 5 of 46 group A patients and 7 of 48 group B patients had a four-fold or greater increase of IgG antibody to CMV eight to twelve weeks postoperatively. IgG antibody titre did not increase in a third group (group C) of 57 seropositive patients who received no RBCs. 10 of the 12 patients with increased IgG titres also had CMV-specific IgM antibody after transfusion. These results indicate that reactivation accounts for most post-transfusion CMV infections in seropositive adults.