The role of EBV, HHV-6 and CMV in pleural effusions of lung transplant recipients

Background: Lymphocytic pleural effusions of unclear etiology are frequent after lung transplantation and are associated with adverse outcomes. Reactivation of human herpesviruses, in particular Epstein-Barr Virus (EBV), has been demonstrated to account for a share of unclear pleural effusions in immunocompetent and -compromised patients. Here, we assessed the detection of human herpesviruses in a large lung transplant pleural effusion cohort. Results: A prospectively sampled cohort of 99 pleural effusions of 67 lung transplant recipients was analyzed for EBV, HHV-6 and CMV by qPCR. A subset of the cohort of 29 effusions was further examined for HSV-1, HSV-2 and HHV-7. Clinical characteristics were compared between EBV-, HHV-6- and CMV-positive versus negative pleural effusions. EBV could be detected in 35%, HHV-6 in 19% and CMV in 4% of assessed pleural effusion samples, whereas HSV-1, HSV-2 and HHV-7 could not be detected. Median viral load for EBV was 1500 copies/ml, for HHV-6 1300 copies/ml and for CMV 163 copies/ml. Overall, no relevant differences were found comparing the characteristics of EBV- and CMV-positive versus negative pleural effusions. HHV-6 positive pleural effusions were predominantly early, postoperative pleural effusions, that had high levels of LDH and were frequently neutrophilic. Conclusion: Herpesviruses can be detected in low copy numbers in a share of lung transplant pleural effusions. However, they do not seem to account for the high rate of unclear lymphocytic effusions after lung transplantation. Publication History Article published online: 04 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany