Subcutaneous immunoglobulin replacement following CD19-specific chimeric antigen receptor T-cell therapy for B-cell acute lymphoblastic leukemia in pediatric patients

Twenty-eight patients were maintained on subcutaneous immunoglobulin replacement for persistent B-cell aplasia and agammaglobulinemia following CD19-targeted chimeric antigen receptor T-cell therapy for B-cell lymphoblastic leukemia. Patients were transitioned from intravenous to subcutaneous immunoglobulin replacement at a median of 11.5 months (range, 4-20). Increasing serum IgG level was significantly associated with a lower rate of sinopulmonary infection (P = 0.0072). The median serum IgG level during infection-free periods was 1000 mg/dL (range, 720-1430), which was significantly higher than IgG levels in patients with sinopulmonary infections. As such, we recommend maintaining a goal IgG level > 1000 mg/dL to provide optimal protection.