[Current recommendations for the diagnosis and treatment of autoimmune hemolytic anemia based on etiology and pathology].

Autoimmune hemolytic anemia (AIHA) is caused by autoantibodies that can be divided into two types-warm and cold-depending on their thermal amplitudes. The pathology differs depending on the type of autoantibody involved; however, the underlying etiology can differ even when the pathology is the same. Therefore, understanding the underlying mechanisms and making an accurate diagnosis is critical, as inappropriate treatment not only results in treatment failure, but can also cause life-threatening complications and reduce patient quality of life. Corticosteroids are the first-line treatment for warm AIHA, but have limited efficacy against cold agglutinin disease (CAD). Moreover, long-term and high-dose administration of corticosteroids increases risk of infection, fracture, and thromboembolism. A novel therapeutic agent for CAD targeting the complement system is effective only against hemolysis, but does not improve symptoms induced by red blood cell aggregation. In addition, elderly patients who present with either warm AIHA or CAD should also be assessed for possible malignancy. This review discusses the etiologies and pathological conditions associated with AIHA and describes the recommendations for diagnosis and treatment according to the Japanese guideline for AIHA revised in 2022.