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.
Hence, while targeting CD19-expressing cells leads to prolonged B-cell aplasia which is clinically benign, targeting myeloid antigens would lead to prolonged myeloablation which is not clinically tolerable.
Despite CD19+ B-cell aplasia in all patients, the incidence of viral infections occurring >90 days post-CD19-CARTx was low (0.91 infections per person-year).
CD19-specific chimeric antigen receptor (CAR)<sup>+</sup> T cells have demonstrated clinical efficacy and long-lasting remissions, concomitant with tolerable normal B-cell aplasia.
In contrast, long-term antibiotic exposure did not affect the efficacy of ACT using CD19-targeting chimeric antigen receptor (CAR) T cells in mice with systemic B-cell lymphoma, although it correlated with prolonged CAR expression and sustained B-cell aplasia.