Comparison of serology assays and polymerase chain reaction for the monitoring of active cytomegalovirus infection in renal transplant recipients

BACKGROUND: Cytomegalovirus (CMV) infection is a common complication of renal transplantation. It can be diagnosed serologically, mainly based on seroconversion or by the detection of viral antigen via CMV-DNA amplification (polymerase chain reaction PCR]). AIM: We sought diagnosis of an active CMV infection in renal transplant patients comparing serologic assays of CMV-IgM antibodies with CMV-DNA amplification. METHODS: We retrospectively studied renal transplant recipients 26 (including 15 women) hospitalized with clinical suspicion of CMV disease. The diagnosis of CMV infection was suspected on the basis of nonspecific symptoms, including fever, leukopenia, hyperbilirubinemia, and alanine aminotransferase elevation, alone or in combination. At the time of admission, all patients were screened for CMV-IgM antibody (immunoassays AxSYM/IMx) and CMV-DNA (qualitative PCR). RESULTS: The confirmation of CMV infection by the two methods (immunoassay and PCR) was obtained in only three patients (11.5%), its unambiguous exclusion--in four cases (15.4%). Nineteen patients (73.1%) were positive for CMV-IgM and negative for CMV-DNA. CONCLUSION: Detection of CMV-IgM antibodies by various immunoassays is not sensitive enough for diagnosis and cannot be used for monitoring during the active period in renal transplant recipients. This observation supported the prolonged presence of IgM antibodies after recent CMV infection in this patient group.