Natural killer cells and cytomegalovirus and Epstein-Barr virus infection in cardiac graft recipients.

The serum of 10 male patients undergoing heart transplantation was found to contain anamnestic antibodies (IgG) against cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Patients with decreased natural killer (NK) cell activity displayed specific IgM against these viruses, a fact suggesting their activation and reproduction. Patients whose NK activity was within the range of that of healthy blood donors did not have serum IgM against CMV and EBV. Decreased NK activity and presence of specific IgM are associated with an increased number of LGL and monocytes, determined both by a monoclonal antibody (MEM-18) against their surface antigen, and morphologically.