TRANSPLANT-RELATED VIRAL INFECTION AND CO-INFECTION RATES

Introduction: Viral replication, as a result of either primary infection or reactivation, represents a significant clinical challenge in both solid organ and hematopoietic stem cell transplant recipients. Reactivation, subsequent to immunosuppression, is of major concern because many patients harbor latent viruses. Many studies have addressed the incidence of viral reactivation in transplant recipients, but few have examined co-infection rates. In a retrospective analysis on infection and co-infection rates of transplant-related viruses, we reviewed qualitative and quantitative real-time PCR results for cytomegalovirus (CMV), BK virus (BKV), Epstein-Barr virus (EBV), parvovirus B19, human herpesvirus 6 (HHV-6) and adenoviruses at Focus Diagnostics.

Methods: We performed a query of our LIS to identify specimens submitted to Focus Diagnostics from transplant centers and for which the ordering physician requested real-time PCR testing for two or more of the following viruses: CMV, BKV, EBV, parvovirus B19, HHV-6 and adenoviruses. After excluding specimens that were not reported due to insufficient sample volume, inhibition of PCR, or indeterminate results, we identified 3,182 such specimens.

Results: The most commonly detected virus in our study was EBV. Of the 2,736 samples tested for this virus, 681 were PCR-positive (24.5%).  The second most common virus was BKV (134 PCR-positive out of 1936), followed by CMV (124/2918), parvovirus B19 (18/157), HHV-6 (18/239) and adenovirus (5/89). Many specimens were positive for more than one virus. Of the 1,678 samples tested for both EBV and BKV, 24 were PCR-positive for both viruses (1.4%). The rate of dual PCR-positivity was 1.3% for the combinations of HHV-6/CMV and HHV-6/parvovirus B19. For the combinations of EBV/CMV and EBV/parvovirus B19, the dual PCR-positivity rate was 1% while the rate for CMV/BK was 0.7%. In addition, two specimens were PCR-positive for BKV, CMV and EBV.

Conclusions: Within the group of specimens submitted for multiple PCR analyses, 26.8% were positive for a single virus, while 2% were positive for more than one virus. In the setting of transplant recipients, monitoring of multiple viruses may be necessary.