[Three cases of hemodiafiltration for the treatment of CAR-T related grade 3 - 4 cytokine release syndrome after ineffective treatment with IL-6 receptor inhibitors].

Objective: To investigate the efficacy and safety of hemodiafiltration (HDF) in treating CAR-T related grade 3-4 cytokine release syndrome after ineffective treatment with IL-6 receptor inhibitors. Methods: Between July 2015 and July 2021, retrospective analysis of hemodiafiltration for the treatment of 3 patients, including 2 cases of acute B-lymphoblastic leukemia and 1 case of diffuse large B-cell lymphoma, with grade 3-4 CRS after CAR-T cell therapy and ineffective treatment with IL-6 receptor inhibitor was carried out. Results: The patient's clinical symptoms, including body temperature, blood pressure, and blood oxygen, were relieved within 12 hours of all treatments, and the cytokines (IL-6, IL-10, TNF-α, INF-γ) and C-reactive protein (CRP) levels decreased significantly. No adverse side effects were observed during the follow-up period of 3 months. Conclusion: HDF can be a safe and feasible method to treat CAR-T related grade 3- 4 CRS after ineffective treatment with IL-6 receptor inhibitors.