The Early Diagnosis and Monitoring of CMV Infection in Renal Transplant Recipients: Comparison Among CMV Antigenemia Assay, PCR, Serology, and Shell Vial Assay

K Tanabe; N Ishikawa; T Tokumoto; K Takahashi; T Yagisawa; H Toma; S Fuchinue; T Kawai and K Ota, Department of Urology and Surgery, Kidney Center, Tokyo Women's Medical College

Purpose: Early diagnosis of CMV infection which is an important cause of morbidity and mortality in renal transplant recipients remains of great importance. This prospective study was performed in kidney transplant recipients to determine the diagnostic value of CMV antigenemia assay in comparison with PCR, serology and shell vial assay.

Materials and Methods: Sixty-three renal transplant recipients were enrolled in this study. The immunocytochemical detection of CMV antigen (CMV antigenemia assay) was performed by a mixture of mouse monoclonal antibodies C10 and C11 directed against the lower matrix protein pp65.

Results: Out of 63 renal transplant patients who were monitored by both antigenemia assay and serology, 28 cases (44%) had symptomatic CMV diseases. Additionally, 34 of 63 patients were also examined by PCR and shell vial assay. Out of these 34 patients, 16 (47%) were symptomatic. PCR and shell vial assay were positive in 15 (94%) and 13 (81%) of the symptomatic CMV disease, respectively. Antigenemia, PCR and shell vial assay became positive before the onset of CMV-related symptoms in 25/28 (89%), 13/16 (81%),and 2/16 (13% ), respectively. None of the 28 patients who had symptomatic CMV disease showed a significant increase of IgG or IgM before the onset of symptoms. Antigenemia and PCR assays turned positive 7 and 11 days, in median, before the onset of clinical symptoms, respectively. Serology and shell vial assay became positive 21 and 25 days in median after the onset of CMV-related clinical symptoms, respectively. To examine the clinical value of these assays, "Good correlation" was defined based on the correlation between clinical course and the results of the assays. "Good Correlation" with the antigenemia assay was observed in 27 (96%) out of 28 renal transplant recipients who recovered from their CMV disease by ganciclovir therapy. Out of 16 (93%) cases only one case showed "Good Correlation" by shell vial assay while PCR and serology did not show a "Good Correlation." Consequently, antigenemia was considered the best way to monitor CMV infections after kidney transplantation.

Conclusion: Only the CMV antigenemia assay can be successfully employed after renal transplantation for the early diagnosis and extensive monitoring of active CMV infection.