CTLA4 and macrophage activation syndrome: CAR: chimeric antigen receptor; CD: cluster of differentiation; CRP: C-reactive protein; CRS: cytokine release syndrome; GVHD: graft-versus-host disease; HSCT: hematopoietic stem cell transplantation; ICANS: immune effector cell-associated neurotoxicity syndrome; IL: interleukin; IFN-γ: interferon-γ; MAS: macrophage activation syndrome; scFy: inhibitory chimeric antigen receptor; TCR: T cell receptor; TNF-α: tumor necrosis factor-alpha; TLS: tumor lysis syndrome