Quantification of cytomegalovirus (CMV) viral load by the hybrid capture assay allows for early detection of CMV disease in lung transplant recipients

Background: We prospectively compared the hybrid capture system (HCS) assay with conventional cell culture and shell vial assay for the detection of cytomegalovirus (CMV) infection and disease in the lung transplant population. Methods: Between January 1999 and February 2000, 34 lung transplant patients at Loyola University Medical Center, who were considered to be at risk for CMV disease, underwent surveillance testing for CMV cell culture, shell vial assay and HCS assay according to a pre-determined schedule. In addition, bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy were performed at regular intervals and for clinical indications. All BAL samples were sent for CMV cultures and biopsy specimens were analyzed for histopathologic evidence of CMV by immunoperoxidase staining using antibody to early immediate nuclear antigen. Results: Ten patients developed CMV disease/syndrome during the course of the study. The sensitivity, specificity, positive predictive value and negative predictive value were > 90% for the HCS assay. The sensitivity of the HCS assay (90%) was statistically significantly higher than the sensitivity of either the SV assay (40%) or the cell culture (50%). In addition, the HCS assay was able to detect CMV 50 67 days prior to clinical evidence of CMV disease and an average of 36 days prior to the other detection techniques. Conclusion: The HCS assay is a sensitive diagnostic technique able to reliably detect CMV disease earlier than other diagnostic methods in the lung transplant population. Future studies may be able to evaluate whether pre-emptive anti-viral therapy targeted to specific viral loads using the HCS assay will be beneficial in preventing morbidity associated with CMV disease.