Cytomegalovirus (CMV) DNA quantification in bronchoalveolar lavage fluid of immunocompromised patients with CMV pneumonia

Cytomegalovirus ( CMV ) pneumonia causes major morbidity and mortality. Its diagnosis requires demonstration of viral cytopathic changes in tissue, entailing risks of lung biopsy. This study aimed to determine CMV viral load ( VL ) thresholds in bronchoalveolar lavage fluid ( BALF ) for diagnosis of CMV pneumonia in immunocompromised patients. CMV VL in BALF was studied in 17 patients (83% transplant recipients) and 21 control subjects with and without CMV pneumonia, respectively, using an FDA ‐approved PCR assay (Cobas ® AmpliPrep/Cobas TaqMan ® CMV Test, Roche Molecular Systems, Inc.) calibrated to the WHO International Standard for CMV DNA ( NIBSC : 09/162). Receiver operating characteristic curve analysis produced a BALF CMV VL threshold of 34 800, IU / mL with 91.7% sensitivity and 100.0% specificity for diagnosis of possible, probable, and proven CMV pneumonia in transplant patients, while a threshold of 656 000 IU / mL yielded 100% sensitivity and specificity among biopsy‐proven cases. For all immunocompromised patients, a VL threshold of 274 IU / mL was selected. VL thresholds also were normalized to BALF cell count yielding a threshold of 0.32 IU /10 6 cells with 91.7% sensitivity and 90.5% specificity for possible, probable, and proven CMV pneumonia in transplant recipients. Monitoring CMV VL in BALF may be a less invasive method for diagnosing CMV pneumonia in immunocompromised patients.