A Prospective Study of Plasma and Bronchoalveolar Lavage Fluid CMV DNA Load Quantification for the Diagnosis and Outcome of CMV Pneumonitis in Immunocompromised Hosts.

Background: Molecular testing has been utilized for cytomegalovirus (CMV) pneumonitis (CMVP) diagnosis, although its validity and optimal cut-off values remain limited.

Methods: A prospective study of CMVP diagnosis among immunocompromised patients was conducted by measuring quantitative CMV DNA polymerase chain reaction in plasma and bronchoalveolar lavage fluid (BALF).

Results: Forty-five adult immunocompromised patients were investigated. Thirty-two patients (71%) received immunosuppressive therapy. Eleven patients (24%) were confirmed to have CMVP. Of those, three and eight patients were classified as proven and probable CMVP, respectively. Median (IQR) plasma CMV DNA loads in CMVP and non-CMVP were 41,939 (4,424-122,608) and 0 (0-44) IU/mL, respectively (p<0.001). Median (IQR) BALF CMV DNA loads in CMVP and non-CMVP were 379,652 (163,800-1,254,000) and 0 (0-1,348) IU/mL, respectively (p<0.001). A significant correlation was observed between plasma and BALF CMV DNA loads (r=0.887, p<0.001). Plasma CMV DNA load of 831 IU/mL was established as a cut-off value for diagnosing CMVP (AUC 0.9987, sensitivity 100%, specificity 94.1%, positive predictive value 84.5%, negative predictive value 100%).

Conclusions: A strongly positive correlation was observed between CMV DNA loads measured in plasma and BALF. CMV DNA load quantification could potentially assist in diagnosing CMVP in immunocompromised patients, although bronchoscopy remains encouraged for a definitive diagnosis.