Borradori L, Gueissaz F, Frenk E, Rohner R, Scherz R, Lantin J P, Späth P J
Service de dermatologie, CHUV, Lausanne.
Schweiz Med Wochenschr. 1991 Mar 23;121(12):418-23.
Inherited deficiencies of classical pathway complement components are rare and associated with autoimmune diseases and with increased susceptibility to bacterial infections. We report the clinical evolution and studies of the complement system in a 17-year-old female patient of Swiss origin presenting with systemic lupus erythematosus (malar rash, photosensitivity, leukopenia and antinuclear antibodies), in whom the hemolytically active second complement component (C2) was less than 10% of the normal value and antigenic C2 was not detectable. Linkage studies showed that the patient is HLA-A25, B18 positive and has the slow factor B allotype BfS. Further immunological assessment revealed low IgG4 concentrations in the patient, who had the G2M(23) allotype. The asymptomatic first degree family members had half-normal C2 levels compatible with a heterozygous state of C2 deficiency. Therapy with hydroxychloroquine for 17 months and topical sunscreen preparations produced marked clinical improvement. During the 4 years of follow-up, the patient has been well and shown only an abnormal titer of antinuclear antibodies. No infections were observed. To the best of our knowledge, 99 cases of homozygous C2 deficiency have been described so far and are discussed here.
经典途径补体成分的遗传性缺陷较为罕见，与自身免疫性疾病以及细菌感染易感性增加有关。我们报告了一名17岁瑞士裔女性系统性红斑狼疮患者（有蝶形红斑、光过敏、白细胞减少和抗核抗体）补体系统的临床演变及研究情况，该患者溶血活性第二补体成分（C2）低于正常值的10%，且未检测到抗原性C2。连锁研究表明，该患者HLA - A25、B18阳性，具有慢因子B同种异型BfS。进一步的免疫学评估显示，该患者IgG4浓度较低，具有G2M(23)同种异型。无症状的一级家庭成员C2水平为正常的一半，符合C2缺陷杂合状态。使用羟氯喹治疗17个月并外用防晒制剂后，临床症状显著改善。在4年的随访期间，患者情况良好，仅抗核抗体滴度异常。未观察到感染情况。据我们所知，目前已报道99例纯合子C2缺陷病例，并在此进行讨论。
