Neutralizing antibody responses to reinfecting strains of cytomegalovirus in transplant recipients.

Analysis of cytomegalovirus (CMV) isolates shed by 51 recipients of organs from 24 CMV-seropositive donors was used to assess the relative characteristics of primary infection, reactivation of endogenous virus, and reinfection by a donor CMV strain. Reinfection was more frequent than reactivation of endogenous virus. Symptomatic CMV disease was identified in 21 of 25 primary infections, 2 of 16 reinfections, and 1 of 4 cases of endogenous reactivation. Before receiving a transplant, reinfected recipients had detectable neutralizing antibody to the specific reinfecting strain of CMV and to laboratory strain AD169. Following reinfection, rises in neutralizing antibody titers were observed, comparable to the responses of those with reactivation of endogenous CMV. The preexisting level of neutralizing antibody did not appear to predict clinical outcome, and moderately high levels of neutralizing antibody did not prevent viremia. Thus, posttransplant CMV reinfection occurs frequently and appears clinically, serologically, and virologically similar to reactivation of endogenous virus.