Immunological consequences of CAR T-cell therapy: an analysis of infectious complications and immune reconstitution
Andreas Riedel, Laurent Phely, Stefan Hug, Philipp Faustmann, Jan C. Schroeder, Britta Besemer, Anna M. Paczulla Stanger, Christoph Faul, Claudia Lengerke, Jan Frederic Weller, Wolfgang Bethge
Abstract
ABSTRACT: Chimeric antigen receptor (CAR) T-cell therapy has demonstrated remarkable efficacy in treating relapsed and refractory (R/R) B-cell neoplasms, such as diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Despite its success, the long-term effects and sequelae of CAR T cells on the immune system remain underexplored. This study presents a 1-year follow-up analysis of 52 patients (42 with R/R DLBCL and 10 with R/R MM) treated with anti-CD19- and B-cell maturation antigen-targeted CAR T cells, focusing on immune reconstitution and infectious complications. Our findings reveal that CAR T-cell therapy leads to profound depletion of B and T cells. CD4+ T cells and CD19+ B cells exhibited impaired regeneration after treatment. Infections were more frequent during the first 30 days. In the short-term follow-up, density of infections within 100 days at risk was 1.8 in patients with DLBCL and 4.6 in patients with MM, with bacterial infections predominating in this early period after CAR T-cell infusion. In addition, we observed a shift to viral infections in the long-term follow-up, alongside with a decline in infection density to 0.1 in patients with DLBCL and 0.4 infections per 100 days at risk in patients with MM, respectively. Severe cytokine release syndrome was associated with a higher risk of late-onset infections. These findings highlight the importance of close monitoring and prophylactic measures in patients undergoing CAR T-cell therapy to reduce infection risks and enhance immune recovery.