Serial Evaluation of Preimmunization Antibody Titers in Lymphoma Patients Receiving Chimeric Antigen Receptor T Cell Therapy

Antibody titers and potential need for immunization has not been formally studied in CAR-T patients. Prior studies have shown CD19 CAR-T can induce persistent B cell aplasia but preserve plasma cells for humoral response. To assess immune repertoire and antibody titer status of CAR-T recipients We conducted a retrospective study of immune cell recovery and antibody titers to vaccines in anti-CD19 CAR-T recipients at Mayo Clinic, Rochester. In our cohort of 95 CAR-T patients, almost half of the patients had low CD4 T and B cell counts prior to CAR-T and remained persistently low post CAR-T. Prior to CAR-T therapy, seronegative rate was lowest for tetanus and highest for pneumococcus irrespective of prior transplant status (within 2 years of CAR-T). At 3 months post CAR-T, overall seronegativity rates were similar when compared to pre-CAR-T levels for the prior transplant and no prior transplant group. For patients who received IVIG, loss of seropositivity was seen for hepatitis A (1/7,14%). No seroconversion was noted for pneumococcus. For patients who did not receive IVIG, loss of seropositivity was seen for pneumococcus (2/5, 40%) and hepatitis A (1/4, 25%). CAR-T recipients commonly experience T cell and B cell lymphopenia and may not have adequate antibody titers against vaccine preventable diseases despite IVIG supplementation. There could be loss of antibody titers post CAR-T, thus highlighting need for re-vaccination. Additional study with long-term follow-up is needed to inform optimal timing of immunization post CAR-T.