Successful treatment of acute B lymphoblastic leukemia relapse in the skin and testicle by anti-CD19 CAR-T with IL-6 knocking down: a case report oleh Ze-Fa Liu, Li-Yun Chen, Jin Wang, Li-qing Kang, Hua Tang, Yao Zhou, Hai-Xia Zhou, Ai-Ning Sun, De-Pei Wu, Sheng-Li Xue