Ichikawa E, Furuta J, Kawachi Y, Imakado S, Otsuka F
Department of Dermatology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba, Ibaraki 305-8575, Japan.
Br J Dermatol. 2001 May;144(5):1080-3. doi: 10.1046/j.1365-2133.2001.04204.x.
A 28-year-old Japanese woman with hereditary complement (C9) deficiency and dermatomyositis is reported. She had a 3-year history of facial erythema and a 1-month history of progressive muscle weakness. Clinical and laboratory findings were suggestive of dermatomyositis; muscle biopsy confirmed an inflammatory myopathy. An unexpected finding, however, was the low titre of serum haemolytic complement (CH50). Treatment with prednisolone resulted in marked clinical improvement but did not affect the CH50 titre. Further investigation revealed a selective and total absence of the ninth complement component (C9), with direct DNA sequence analysis revealing a non-sense mutation at Arg95 of the C9 gene. This case demonstrates that the muscle lesions of dermatomyositis can occur in the presence of a complement defect that would prevent the formation of the C5b-9 membrane attack complex.
报告了一名患有遗传性补体（C9）缺乏症和皮肌炎的28岁日本女性。她有3年面部红斑病史和1个月进行性肌肉无力病史。临床和实验室检查结果提示为皮肌炎；肌肉活检证实为炎性肌病。然而，一个意外发现是血清溶血补体（CH50）滴度较低。泼尼松龙治疗使临床症状明显改善，但未影响CH50滴度。进一步检查发现第九补体成分（C9）选择性完全缺失，直接DNA序列分析显示C9基因的精氨酸95处存在无义突变。该病例表明，在存在补体缺陷从而阻止C5b - 9膜攻击复合物形成的情况下，皮肌炎的肌肉病变仍可发生。
