Polymyositis and HTLV‐I antibodies
Polymyositis and HTLV‐I antibodies
复制标题
多发性肌炎和 HTLV-I 抗体
作者：
D. Francis;R. Hughes
I 型病毒 (HTLV-I) 被确定为 80% 热带痉挛性截瘫 (TSP) 患者的重要病原体 111。最近的一项研究表明，牙买加患者的 HTLV-I 血清阳性与多发性肌炎之间可能存在相关性 [2]。研究中描述的携带 HTLV-I 抗体的特立尼达妇女同时患有这两种情况。 32岁时，她的下肢出现轻度无力，伴有绊倒和频繁跌倒的倾向。她于 39 岁时来到英国，并于 44 岁时就诊，有 9 个月的进行性肢带无力和肌肉压痛病史，但没有感觉症状。无相关家族史。检查发现近端肢体肌肉无力、触痛。她的深部腱反射活跃，腹部反射缺失，足底伸肌反应消失。没有颅神经或感觉异常。检查显示血细胞计数、红细胞沉降率和甲状腺功能正常，自身抗体筛查呈阴性。 HTLV-I抗体呈阳性（颗粒凝集试验：阳性；ELISA法；滴度，1:256,000），肌酸激酶（CK）升高至1,276 U/L（正常<205）。脑脊液每微升含有 2 个淋巴细胞，蛋白质为 15 mg/dl，IgG 为 7.2 mddl，IgG/白蛋白比值为 0.43（正常 < 0.2 1）。肌电图显示频繁的低幅多相电位，三角肌活检显示局灶性坏死和单核细胞浸润，与多发性肌炎一致。脊髓造影正常。磁共振图像脑部扫描（T2 加权）显示，整个大脑半球白质中存在多个信号改变的小焦点区域，与脱髓鞘一致。在高剂量隔日泼尼松龙治疗后，她的肌肉症状几乎完全缓解，CK 恢复正常。现年 49 岁的她身体状况良好，但依赖性很强。当泼尼松龙剂量隔日减少至 10 毫克以下时，症状会再次出现。该患者符合热带痉挛性截瘫和多发性肌炎的诊断要求。据我们所知，此前尚未在 HTLV-I 血清阳性患者中报道过这种组合。 HTLV-I 和 TSP 之间关联的性质尚未得到解释，其在多发性肌炎中的假定作用需要进一步确认和研究。本例患者从出现脊髓病症状到出现多发性肌炎的时间较长，提示不同的致病机制。直接神经性感染可能在 TSP 中更为重要，而自身免疫从正常抑制机制中逃脱是多发性肌炎更可能的机制。
virus type I (HTLV-I) is established as an important etiological agent in 80% of patients with tropical spastic paraparesis (TSP) 111. A recent study has shown an additional possible correlation between HTLV-I seropositivity and polymyositis in Jamaican patients [2]. The Trinidadian woman with HTLV-I antibodies described in the study has both conditions. At age 32 she developed mild weakness in her lower limbs associated with a tendency to trip and frequent falls. She came to the United Kingdom at age 39 and presented at age 44 with a 9-month history of progressive limb girdle weakness and muscle tenderness but no sensory symptoms. There was no relevant family history. Examination revealed weak, tender proximal limb muscles. Her deep tendon reflexes were brisk, abdominal reflexes absent, and plantar responses extensor. There were no cranial nerve or sensory abnormalities. Investigations showed normal blood count, and erythrocyte sedimentation rate, and thyroid function, and the autoantibody screen was negative. HTLV-I antibodies were positive (the particle agglutination test: positive; ELISA method; titer, 1:256,000) and creatine kinase (CK) was increased to 1,276 U/L (normal < 205). The cerebrospinal fluid contained 2 lymphocytes per microliter, protein was 15 mg/dl, and IgG was 7.2 mddl with IgG/albumin ratio 0.43 (normal < 0.2 1). Electromyography revealed frequent lowamplitude polyphasic potentials, and a deltoid muscle biopsy showed focal necrosis and mononuclear cell infiltrates, consistent with polymyositis. Myelography was normal. A magnetic resonance image brain scan (T2 weighted) demonstrated multiple small focal areas of altered signal throughout the white matter of both cerebral hemispheres consistent with demyelination. On high-dose alternate-day prednisolone her muscle symptoms almost completely remitted and the CK returned to normal. Now aged 49, she remains well but stergid dependent; symptoms recur when the prednisolone dose is reduced below 10 mg on alternate days. This patient fulfills the diagnostic requirements for both tropical spastic paraparesis and polymyositis. To our knowledge this combination has not been reported before in a patient seropositive for HTLV-I. The nature of the association between HTLV-I and TSP has yet to be explained and its putative role in polymyositis requires further confirmation and study. The long delay from the onset of the myelopathic symptoms to the appearance of the polymyositis in our patient suggests differing pathogenic mechanisms. Direct neurotropic infection might be more important in TSP, whereas the escape of autoimmunity from normal suppressor mechanisms is a more likely mechanism for polymyositis.