CAR T cell therapy, a treatment for hematologic malignancies, has been found to weaken vaccine immunity, leaving patients vulnerable to multiple vaccine-preventable pathogens. Despite stable overall antibody levels, a prospective study revealed significant gaps in seroprotection.
The research examined pathogen-specific humoral immunity in patients receiving therapy targeting CD19, CD20 (which affects B cells), or B cell maturation antigen. Antibody responses were measured before and up to one year after treatment.
Findings showed that by one year post-therapy, seroprotective antibodies were absent for up to one-third of routine vaccine-preventable pathogens in patients receiving CD19 or CD20 targeted therapy. This deficit was more pronounced in those treated for plasma cells via B cell maturation antigen, where nearly half lacked adequate seroprotection.
Clinicians are urged to consider these findings, as protective immunity against specific pathogens may be insufficient despite preserved total antibody levels. Pre-vaccination B cell count emerged as the primary predictor of effective immune response post-treatment.