Cytomegalovirus diagnosis in BALF of immunocompromised patients and its association to outcome

<bold>Background:</bold> This study aimed to evaluate the impact of lower respiratory tract infections (LRTIs) caused by CMV, as diagnosed through polymerase chain reaction (PCR) testing of bronchoalveolar lavage fluid (BALF). <bold>Methods:</bold> 2,666 visits involving 1,301 immunocompromised patients with symptoms of LRTI underwent diagnostic BAL, with 235 cases testing PCR positive for CMV in BALF. Main diagnosis were haematological (n=88), solid organ transplantation (n=70), and other forms of immunosuppression (n=77). The primary composite outcome encompassed predefined modifications in patient management within 30 days following bronchoscopy. <bold>Results:</bold> Overall 59 cases exhibited isolated CMV infection, while 176 displayed coinfections. Isolated CMV infection was associated with more macrophages in BALF (75.5%, CI: 44.0 – 85.0). Coinfection was associated with neutrophilia in BALF (haematological 23.25% CI: 4.25-67.0; others 35.00%, CI 10.0-65.00). BAL findings prompted treatment modifications in 61.7% (n=145) of all CMV-BALF positive cases. The 30-day mortality rate stood at 13.6%, with a significantly elevated hazard ratio for those with CMV-positive BAL PCR diagnosis (unadjusted HR 2.85, 95%CI: 1.86-4.36). <bold>Conclusion:</bold> This study underscores the pivotal role of bronchoscopy with BAL in altering the management of immunocompromised patients with CMV-related infections, with mortality risk nearly tripling in patients with a positive CMV PCR in BAL fluid.