Respiratory Viral Infections Following CD19 CAR T-Cell Therapy.

Respiratory viral infections (RVI) are an important infectious complication after chimeric antigen receptor (CAR) T-cell therapy. However, the epidemiology of RVI following CAR T-cell therapy and their risk factors are not well defined. To describe the incidence, epidemiology, and clinical characteristics of RVI in patients who have received CD19 CAR T-cell therapy and identify independent risk factors for infection, we performed a retrospective, single-center cohort study including 101 patients treated with CD19 CAR T-cell therapy between April 2018 and January 2023. Demographic, clinical, and infection characteristics were recorded and compared among patients who did and did not develop RVI within 18 months of CAR T-cell infusion. Logistic regression was performed to assess for predictors of RVI. Among the 101 CAR T-cell recipients, 32 RVIs were diagnosed in 21 individuals (20.8%) for an infection density of 34 infections/100 person-years. SARS-CoV-2 was the most common cause of RVI (17, 53.1%). Infection severity was usually mild (56%) or moderate (41%) with only 1 patient developing severe RVI. We found that elevated BMI was associated with higher odds of RVI (OR 1.13, 95% CI 1.04, 1.23). This study provides detailed information on the clinical characteristics of RVI in patients following CAR T-cell therapy. RVI were a common complication following CAR T-cell therapy, but tended to be mild in severity and generally decreased in frequency with time. Larger prospective studies will be necessary to fully characterize risk factors for RVI and interventions that may reduce their incidence.