Chimeric antigen receptor T cell immunotherapy‑associated hemophagocytic lymphohistiocytosis: Pathogenesis, clinical manifestation, diagnosis and management compared with cytokine release syndrome (Review).

Chimeric antigen receptor (CAR) T cell therapy is used to treat hematological malignancy. However, it carries the risk of life‑threatening inflammatory toxicity, including cytokine release syndrome (CRS) and CAR T cell‑associated hemophagocytic lymphohistiocytosis (CARHLH). CRS is a common side effect of CAR T cell therapy, with fever and multiorgan functional impairment as the primary clinical manifestation. CARHLH and CRS have similar clinical manifestations. However, CARHLH is associated with a high mortality rate. CARHLH was previously considered a specific type of CRS, however, it must be promptly differentiated from CRS for treatment initiation, with management differing from that of CRS. The pathogenesis of CARHLH differs from that of CRS. The present review aimed to summarize the pathogenesis, diagnosis and treatment of CARHLH to assist in its early identification and management.