Studies of cytomegalovirus infection in renal allograft recipients. II. Serological response to various viral antigens.

In a prospective study the antibody response to various cytomegalovirus (CMV) antigens was examined in 28 renal allograft recipients. Both primary and secondary infections were investigated. Antibodies against immediate early (IEA) and early antigens (EA) were studied by anti-complement immunofluorescence; IgM and IgG antibodies to nuclear late antigens were differentiated by enzyme-linked immunosorbent assay (ELISA). The results of the tests were compared with each other and with those of the complement fixation (CF) test. 5/7 susceptible patients (71%) contracted primary infections. Both IgM and IgG antibodies developed and antibodies to IEA and EA appeared somewhat later. The antibodies to IEA and EA remained detectable throughout the observation period. Secondary infections developed in 20/21 (95%) patients. All initially had CMV antibody levels in ELISA and CF. Rising CMV titers of IgG antibodies were taken as a measure of secondary infection. IgM antibodies developed in only 10/20 (50%) patients. The highest titers of CMV IgM antibody levels were lower in secondary than in primary infections. Antibodies to IEA and EA were present prior to transplantation in some patients, but did not develop in all with secondary infections. The antibody titers were lower just after than before the transplantation in some patients. but subsequently increased again. It thus seems as if the humoral immune response to these CMV antigens differs in primary and secondary infections.