我们介绍了一名 55 岁女性出现微血尿、蛋白尿和低补体血症的病例，她正在接受英夫利昔单抗生物仿制药 (IFX-BS) 治疗类风湿性关节炎 (RA)。肾活检显示狼疮性肾炎（ISN/RPS 分类 IV 级 V）。停止使用 IFX-BS 治疗，并开始使用泼尼松龙、羟氯喹和阿巴西普治疗，导致狼疮肾炎和 RA 的临床缓解。尽管已知肿瘤坏死因子-α (TNF-α) 抑制剂可诱导自身抗体产生，但症状通常仅限于皮肤受累或关节炎，肾脏并发症很少见。医生应意识到狼疮性肾炎的风险，并仔细监测患者在使用 TNF-α 抑制剂治疗期间是否出现肾脏受累的情况。© 日本风湿病学院 2023 年。由牛津大学出版社出版。版权所有。如需权限，请发送电子邮件至：journals.permissions@oup.com。

We present a case of microhematuria, proteinuria and hypocomplementemia that developed in a 55-year-old female who was being treated with an infliximab biosimilar (IFX-BS) for rheumatoid arthritis (RA). Renal biopsy showed lupus nephritis (ISN/RPS classification class IV+V). Treatment with the IFX-BS was discontinued, and treatment with prednisolone, hydroxychloroquine and abatacept was started, resulting in clinical remission of lupus nephritis and RA. Although tumor necrosis factor-α (TNF-α) inhibitors are known to induce production of autoantibodies, symptoms are usually limited to skin involvement or arthritis, and renal complications are rare. Physicians should be aware of the risk of lupus nephritis and carefully monitor patients for the development of renal involvement during treatment with TNF-α inhibitors.© Japan College of Rheumatology 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.