Systemic lupus erythematosus (SLE) patients have an increased risk of cardiovascular disease and thrombotic events, and the presence of antiphospholipid antibodies further raises the risk of these complications. Here we report a case of a patient with SLE and triple positivity for antiphospholipid antibodies who developed a popliteal artery thrombosis in the context of a severe hyperhomocysteinemia after the introduction of methotrexate (MTX) treatment. MTX is one of the most prescribed medications for a wide spectrum of autoimmune diseases, including SLE. On the other hand, by interfering with folate metabolism, it may induce hyperhomocysteinemia, which, in turn, may increase the risk of vascular complications. Current recommendations suggest screening and, when possible, treating classical and disease-related cardiovascular risk factors in all lupus patients. Based on what observed in our case, we suggest a follow-up of homocysteine levels after the introduction of drugs capable of inducing hyperhomocysteinemia, such as MTX, in SLE patients at high cardiovascular risk.

中文翻译：

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具有抗磷脂抗体的系统性红斑狼疮患者甲氨蝶呤诱导的高同型半胱氨酸血症引发动脉血栓形成

系统性红斑狼疮（SLE）患者患心血管疾病和血栓事件的风险增加，而抗磷脂抗体的存在进一步增加了这些并发症的风险。在此，我们报告一例抗磷脂抗体三重阳性的系统性红斑狼疮患者，在采用甲氨蝶呤 (MTX) 治疗后，在严重高同型半胱氨酸血症的情况下出现腘动脉血栓形成。MTX 是治疗包括 SLE 在内的多种自身免疫性疾病最常用的药物之一。另一方面，通过干扰叶酸代谢，它可能诱发高同型半胱氨酸血症，进而可能增加血管并发症的风险。目前的建议建议对所有狼疮患者进行筛查，并在可能的情况下治疗经典的和疾病相关的心血管危险因素。根据我们病例中观察到的情况，我们建议在心血管高风险的 SLE 患者中使用能够诱发高同型半胱氨酸血症的药物（例如 MTX）后，对同型半胱氨酸水平进行随访。