Katsumata Yasuhiro, Suzuki Takahiro, Kuwana Masataka, Hattori Yutaka, Akizuki Satoshi, Sugiura Hitoshi, Matsuoka Yasuo
Department of Internal Medicine, Kawasaki Municipal Hospital, Kanagawa, Japan.
Arthritis Rheum. 2003 Jun;48(6):1647-51. doi: 10.1002/art.10965.
Amegakaryocytic thrombocytopenia (AMT) associated with systemic sclerosis (SSc) has been described in several case reports, but the underlying mechanisms have not been identified. Here we describe a rare case of SSc accompanied by thrombocytopenia and megakaryocytic hypoplasia, in which autoantibody against thrombopoietin receptor (c-Mpl) was detected. A 61-year-old woman with limited SSc was admitted to our hospital because of severe thrombocytopenia (platelet count 0.2 x 10(4)/mm(3)) with gingival bleeding. Her bone marrow was hypocellular with absent megakaryocytes, consistent with AMT. Treatment with corticosteroids and intravenous immunoglobulin infusions resulted in an increased platelet count, and she sustained a remission over a 1-year period, with a platelet count averaging 10.0 x 10(4)/mm(3). Her serum was strongly positive for anti-c-Mpl antibody, and IgG fraction purified from her serum inhibited thrombopoietin-dependent cell proliferation in vitro. Our case report suggests that AMT in patients with SSc could be mediated by the anti-c-Mpl antibody, which functionally blocks an interaction between thrombopoietin and c-Mpl.
几例病例报告中描述了与系统性硬化症（SSc）相关的无巨核细胞性血小板减少症（AMT），但其潜在机制尚未明确。在此，我们描述了1例罕见的伴有血小板减少症和巨核细胞发育不全的SSc病例，该病例中检测到了抗血小板生成素受体（c-Mpl）自身抗体。1名61岁的局限性SSc女性因严重血小板减少症（血小板计数0.2×10⁴/mm³）伴牙龈出血入住我院。其骨髓细胞减少，无巨核细胞，符合AMT表现。使用糖皮质激素和静脉输注免疫球蛋白治疗后血小板计数升高，她在1年期间维持缓解状态，血小板计数平均为10.0×10⁴/mm³。其血清抗c-Mpl抗体呈强阳性，从其血清中纯化的IgG组分在体外可抑制血小板生成素依赖性细胞增殖。我们的病例报告提示，SSc患者的AMT可能由抗c-Mpl抗体介导，该抗体在功能上阻断了血小板生成素与c-Mpl之间的相互作用。
