Infections after CD19 CAR T-cell therapy in a middle-income country: real-world data and review of endemic pathogens

• Tailored infectious screening, including endemic pathogens, is critical in CAR-T candidates in endemic areas. Infectious complications remain a major concern after CAR-T cell therapy, particularly in low- and middle-income countries where endemic pathogens may increase risk. We retrospectively studied 23 patients with relapsed/refractory B-cell malignancies (18 diagnosed with Diffuse Large B-cell Lymphoma, three with Acute Lymphoblastic Leukemia, and two with Follicular Lymphoma) treated with CD19-directed CAR-T therapy (tisagenlecleucel or axicabtagene ciloleucel) at a single Brazilian center between February 2023 and January 2025. During a median follow-up of 124 days, 33 infectious episodes occurred, including 18 early (≤30 days) and 15 late (>30 days) events. Consistent with existing literature, the highest incidence was within the first month post-infusion, with bacterial infections, Candida spp , and CMV reactivation predominating, whereas respiratory viral infections were more frequent thereafter. Three patients developed endemic infections (tuberculosis, cryptococcosis, and giardiasis). CMV reactivation and probable aspergillosis were observed in 13% of patients each. Overall, 10 patients died, including 2 from infection and 8 from disease progression. A complementary literature review regarding endemic infections following CAR-T cell therapy was performed, highlighting tuberculosis, endemic fungal, and protozoan infections as important considerations for post-CAR-T management in endemic areas. Our findings emphasize the importance of early surveillance for infectious complications after CAR-T therapy, including attention to endemic pathogens in Latin America.