慢性或成人自身免疫性血小板减少性紫癜(ITP)常常产生高水平的血小板相关IgG抗体和/或IgM抗体,但补体介导的血小板减少尚未阐明。作者报道一例慢性ITP体内存在相对低水平单克隆IgM κ型副蛋白,对血小板有强亲和力,能激活补体,用皮质类固醇激素和长春新碱治疗无效,脾切除后暂时有效。病例示范患者,64岁,白人男性,1983年12月出现鼻衄、皮下淤斑,严重血小板减少3 000—16 000/mm~3,白细胞6900/mm~3,血红蛋白12.0g/dl,单克隆IgM κ型副蛋白0.3g/dl。外周血镜检未见血小板丛集,骨髓内异常淋巴样细胞浸润,这些细胞抗酒石酸盐染色,酸性磷酸酶阳性,镜下无毛细胞白血病细 Chronic or adult autoimmune thrombocytopenic purpura (ITP) often produces high levels of platelet-associated IgG and / or IgM antibodies, but complement-mediated thrombocytopenia has not been elucidated. The authors report that there is a relatively low level of monoclonal IgM κ-type paraprotein in chronic ITP that has strong affinity for platelets, activates complement, is ineffective with corticosteroids and vincristine, and is transiently effective after splenectomy. The patient was 64 years old and white male. In December 1983, epistaxis, subchondral ecchymosis, severe thrombocytopenia of 3 000-16 000 / mm 3, white blood cell 6900 / mm 3, hemoglobin 12.0 g / dl, monoclonal IgM κ-type paraprotein 0.3 g / dl. Peripheral blood microscopy showed no platelet aggregation, abnormal bone marrow infiltration of lymphoid cells, these cells anti-tartrate staining, acid phosphatase positive, microscopic hairless cell leukemia thin