目的　寻找狼疮肾炎 (LN)患者中抗中性粒细胞胞质抗体 (ANCA)的未知靶抗原 ,并分析其相应抗体与临床和病理损害的关系。方法　收集 72例有完整临床病理资料的狼疮肾炎患者的血清 ,分离健康人外周血中性粒细胞的初级颗粒和次级颗粒制备成酸性可溶性颗粒蛋白抗原液 ,以此为抗原在非还原状态下进行Western blot分析 ,检测狼疮肾炎患者血清中的ANCA。结果　部分血清可识别一些蛋白条带 ,其中 1 4 / 72 (1 9 4% )例识别分子量为 690 0 0的蛋白条带 ,后者不同于ANCA其他已知的靶抗原如组织蛋白酶G和乳铁蛋白等 ;1 0 / 72 (1 3 9% )例识别 55 0 0 0的蛋白条带 ,后者可能是杀菌 /通透性增高蛋白。进一步的研究发现 ,在抗 690 0 0蛋白抗体阳性的病人中 ,光过敏和口腔溃疡的发生率均显著高于抗 690 0 0蛋白抗体阴性者 (分别为 57 1 %、1 2 1 % ,P <0 0 0 5 ;50 0 %、1 7 2 % ,P <0 0 5)。结论　中性粒细胞混合颗粒中的 690 0 0蛋白可能为狼疮肾炎ANCA新的特异性靶抗原 ,抗 690 0 0蛋白抗体可能与狼疮肾炎患者光过敏和口腔溃疡相关。 Objective To search for unknown target antigens of anti-neutrophil cytoplasmic antibody (ANCA) in patients with lupus nephritis (LN) and to analyze the relationship between their corresponding antibodies and clinical and pathological lesions. Methods Seventy-two patients with lupus nephritis with complete clinical and pathological data were collected, and the primary particles and secondary particles of peripheral blood neutrophils were isolated from healthy volunteers to prepare acidic soluble granule protein antigen solution, which was used as antigen in non-reducing state Western blot analysis was performed to detect ANCA in the serum of patients with lupus nephritis. Results Some serums could identify some protein bands, of which 14/72 (1 94%) identified protein bands with a molecular weight of 690 0, which was different from other ANCA known target antigens such as cathepsin G and milk Ferritin, etc .; 10/72 (139%) cases of protein identification of 55 0 0 0, the latter may be bactericidal / permeability increased protein. Further studies found that the incidence of photo-sensitivity and oral ulcer were significantly higher in patients with anti-690 0 antibody than those with anti-690 0 antibody (571%, 121%, respectively <0 0 0 5; 50 0%, 1 72%, P <0 05). Conclusions 690 0 0 protein in neutrophil granule may be the new specific target antigen of ANCA in lupus nephritis. The anti-690 0 0 antibody may be associated with hypersensitivity and oral ulcer in patients with lupus nephritis.