Cytomegalovirus in Bronchoalveolar Lavage Fluid: A Predictor of Outcome in Immunocompromised Patients

ABSTRACT

Cytomegalovirus (CMV) is a prevalent herpesvirus that remains typically asymptomatic in immunocompetent individuals but can cause severe, potentially life‐threatening disease in immunocompromised patients. This study assessed the impact of CMV‐associated lower respiratory tract infections (LRTIs), diagnosed by polymerase chain reaction (PCR) testing of bronchoalveolar lavage fluid (BALF), focusing on coinfections and clinical outcomes. Between 2009 and 2017, a total of 2666 visits involving 1301 immunocompromised patients with suspected LRTI who underwent diagnostic bronchoalveolar lavage (BAL) were analyzed. The primary outcomes included CMV detection in BAL and resulting treatment modifications. Among these, 235 BALFs from 157 patients tested positive for CMV. Among these CMV‐positive cases, immunosuppression was classified as hematological conditions ( n  = 88), solid organ transplantation ( n  = 70), or other causes of immunosuppression ( n  = 77). Overall, 59 cases exhibited isolated CMV infection, which was associated with a higher percentage of macrophages in BALF, compared to cases with CMV and coinfection [75.5%, 95% confidence interval (CI): 44.0–85.0 vs. 37.5%, 95% CI: 11.5%–67.0%, p  = 0.008]. A total of 176 cases demonstrated CMV and coinfection, which were associated with neutrophilia in BALF (49.5%, 95% CI: 15.5–82.5; vs. CMV‐monoinfection: 7.5%, 95% CI:2–36, p  = 0.002). BAL findings prompted treatment modifications in 61.7% ( n  = 145) of all CMV‐positive cases. The 30‐day mortality rate was 13.6%, with a significantly elevated hazard ratio for those with CMV‐positive BAL diagnosis (unadjusted HR 2.85, 95% CI: 1.86–4.36). Cases with a CMV infection exhibited a significantly higher probability of requiring hospitalization compared to CMV‐negative cases, (OR 1.39, 95% CI: 1.03–1.87, p  = 0.030). Immunocompromised patients have an increased risk of CMV infection, and the presence of CMV does not exclude a coinfection with other respiratory viruses, bacteria, or fungi. CMV detection in BALF was associated with higher hospitalization rates and mortality. Preventive and preemptive antiviral strategies are crucial, especially given the adverse impact of coinfections.