少数自身免疫性溶血性贫血(AIHA)伴有特发性血小板减少性紫癜(ITP),称之为Evans′综合征。通常AIHA直接抗球蛋白试验(DAT)阳性,阴性者少见。作者报告1例DAT阴性的Evans′综合征含有自身抗Jk~a抗体。抗Jk~a作为自身抗体出现罕见。患者为高加索人,34岁,因呼吸困难2天入院。既往健康,无输血史。体检发现苍白及中度黄疸。血红蛋白4.9g/dl,白细胞10.5×10~9/L,血小板496×10~9/L,网织红细胞6.8%(绝对值115×10~9/L),血片示球形红细胞增多,骨髓红系增生,巨核细胞正常,诊断为AIHA。经输注9个单位的压积红细胞及强的松龙治疗后,血红蛋白升至11.8g/dl,但血小板降至13×10~9/L,骨髓中巨核细胞增多,此时已发生 A few autoimmune hemolytic anemia (AIHA) with idiopathic thrombocytopenic purpura (ITP), known as Evans’ syndrome. Usually AIHA direct antiglobulin test (DAT) positive, negative are rare. The authors report that 1 case of DAT-negative Evans’ syndrome contains its own anti-Jk-a antibody. Anti-Jk ~ a appears as an autoantibody rare. The patient was Caucasian, 34 years old and admitted to hospital for 2 days because of dyspnea. Past health, no history of blood transfusions. Physical examination found pale and moderate jaundice. Hemoglobin 4.9g / dl, white blood cells 10.5 × 10 ~ 9 / L, platelets 496 × 10 ~ 9 / L, reticulocyte 6.8% (absolute value 115 × 10 ~ 9 / L), blood cells showed spherocytosis, Department of hyperplasia, megakaryocytes normal, diagnosed as AIHA. After transfusion of 9 units of hematocrit and prednisolone, hemoglobin rose to 11.8g / dl, but the platelet decreased to 13x10 ~ 9 / L, the proliferation of megakaryocytes in the bone marrow at this time has taken place