Reduced ABO blood group antibody titers in patients after CD19 CAR-T cell therapy.

With rapid developments in genetic engineering, tumor immunology, and cellular engineering, chimeric antigen receptor T cell (CAR-T) cell therapy has become a novel immunotherapy for oncology and other medical fields.1 The promising results of CD19 CAR-T treating B-cell malignancies were reported.2,3 Simultaneously, there existed many adverse events, the most reported of which including B-cell aplasia, hematological toxicity, cytokine release syndrome (CRS), and immune effector-cell–associated neurotoxicity syndrome (ICANS),3,4 but there is still lack of reports demonstrating the impact of CD19 CAR-T on the ABO blood group potency of patient’s serum. Blood transfusion plays an important role in treating diseases, especially in treating hematological diseases, and the accurate identification of ABO blood groups is a prerequisite for the safe blood transfusion. Meanwhile, the valid measurement of patient’s serum ABO blood group antibody potency is essential for the identification of the patient’s ABO blood group type. In this case report, we summarized the data of 10 patients receiving CD19 CAR-T cell immunotherapy in our hospital in recent years and had their potency measured after treatment, with a view to conducting a preliminary analysis of the impact of CD19 CAR-T cell therapy on the ABO blood group antibody potency in patients’ serum. 2. CASE REPORTS