Cytolytic IgM antibody to cytomegalovirus in primary cytomegalovirus infection in humans.

Suspensions of cytomegalovirus (CMV)-infected human foreskin fibroblasts were used to measure cytolytic antibody (CyA) to CMV in serum by a 51Cr release assay. CyA was associated with IgM but not with IgG antibody to CMV, required rabbit or human complement, and was directed at a surface antigen. CyA was detectable for one to three months in the sera of 16 patients with community-acquired CMV infection and in the sera of 20 of 22 renal transplant recipients with primary CMV infection. CyA was found less frequently in the sera of renal transplant recipients with reactivated CMV infection and occurred almost exclusively when the donor was seropositive for CMV. One individual, unlike many patients with CyA, was free of symptoms. Sera from patients with either rheumatoid factor-positive arthritis or heterophil-positive infectious mononucleosis and from 70 of 71 control patients with other types of antibody to CMV yielded no 51Cr release.