Impact of CD19 CAR T-Cell Therapy on Pathogen-Specific Antibody Titers in Lymphoma Patients

CD19-directed chimeric antigen receptor (CAR) T-cell therapy has exhibited efficacy in treating relapsed/refractory high-grade B-cell malignancies, but off-tumor effects cause prolonged hypogammaglobulinemia and B-cell aplasia. Limited data exist on pathogen-specific IgG titers post-CD19 CAR T-cell therapy.

We evaluated the impact of CD19 CAR T-cell therapy on vaccine-preventable infectious disease IgG titers in 20 patients to assess humoral immunity. IgG titers for measles virus (MeV), mumps virus (MuV), rubella virus (RuV), varicella zoster virus (VZV), pneumococcal capsular polysaccharide, Haemophilus influenzae type B (Hib), and tetanus toxoid were measured at baseline and Day 100 post-CD19 CAR T-cell therapy.

Seropositivity for all pathogens remained stable from baseline to Day 100. Quantitative IgG titers for MeV, MuV, RuV, VZV, and tetanus also remained stable. Median pneumococcal IgG and Hib IgG titers declined (p < 0.05); however, no arbitrary fourfold decreases were observed. Median total IgG concentrations declined (p < 0.05).

MeV, MuV, RuV, VZV, and tetanus toxoid IgG remained stable following CD19 CAR T-cell therapy, while pneumococcal and Hib IgG titers showed marginal quantitative declines, without any fourfold reductions. Overall, humoral immunity at Day 100 following CD19 CAR T-cell therapy remained largely preserved. These seroprevalence findings suggest that routine revaccination may not be required in our patient cohort and highlight the importance of patient monitoring to inform revaccination decisions.