Human cytomegalovirus load in plasma and bronchoalveolar lavage fluid: A longitudinal study of lung transplant recipients

Background. In lung transplant recipients (LTRs), the measurement of human cytomegalovirus (HCMV) load dynamics in the local environment of the lung allograft may offer distinct advantages over their assessment in the peripheral blood compartment. Methods. We compared HCMV load in paired bronchoalveolar lavage (BAL) and plasma samples in a prospective cohort of LTRs. Results. In all, 182 paired samples were collected from 41 LTRs. Qualitative findings were concordant for 79.7% of the paired samples (virus load detected or absent in 8.1% and 71.5% of paired samples, respectively). In 35 paired samples (20.3%), HCMV was detected in the BAL but not the plasma sample; the converse was not found for any of the paired samples. HCMV inclusions were histologically detected in the lungs of 8 patients on 9 occasions. HCMV was detected in both BAL and plasma samples on 7 of the 9 occasions and in only the BAL sample on 2 occasions. Application of a threshold virus load in BAL samples, to predict histologically proven HCMV infection, was associated with improved diagnostic sensitivity and specificity. Conclusions. Quantification of HCMV in the lung allograft correlates with histological detection and, in addition, offers the potential to monitor subclinical viral replication in the lung allograft.