Comparison of Qualitative PCR and pp65 Antigenemia for the Diagnosis of CMV Infection in Hematopoietic Stem Cell Transplanted Patients

Objectives: Human cytomegalovirus (CMV) is a major life-threatening pathogen for hematopoietic stem cell transplant recipients. Specific tests are used for the diagnosis and monitoring of CMV infection in transplant patients. This study evaluates the performance of pp65 antigenemia and qualitative PCR assays for monitoring CMV in such patients. Methods: We analyzed 179 clinical samples from 41 patients by using a validated homebrewed qualitative PCR and a commercial antigenemia assay. The obtained results were evaluated using quantitative real-time PCR as the gold standard. Results: CMV was observed in 26.8% of samples analyzed by the antigenemia assay and in 42.6% of the samples by qualitative PCR. Among 179 clinical samples, 50.8% were negative and 21.2% were positive by both assays. On the other hand, 26.3% were only positive by qualitative PCR whereas 1.7% were positive by the antigenemia assay. A comparison of the results with real-time PCR showed that qualitative PCR has a higher sensitivity than the antigenemia assay (98.7% vs. 45.7%). The specificity of both assays was equal (96.8%). Quantitative results of the antigenemia assay showed good correlation with real-time PCR (r=0.715; p<0.001). Conclusion: Both the qualitative PCR and antigenemia assays have special deficiencies for efficient diagnosis of CMV infection. Therefore, effective management of CMV infection in transplant patients requires the use of other sensitive quantitative methods such as qPCR.