Muro Yoshinao, Ishikawa Asuka, Sugiura Kazumitsu, Akiyama Masashi
Division of Connective Tissue Disease and Autoimmunity, Department of Dermatology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Rheumatology (Oxford). 2012 Aug;51(8):1508-13. doi: 10.1093/rheumatology/kes073. Epub 2012 Apr 25.
Myositis-specific autoantibodies (MSAs), which characterize certain forms of inflammatory myopathy, are useful in the diagnosis and prediction of prognosis in DM/PM. Anti-transcriptional intermediary factor 1-α (TIF1-α) antibodies were recently reported to be associated with cancer-associated DM in conjunction with anti-TIF1-γ antibodies. This study aimed to identify a subset of DM patients who have anti-TIF1-α antibodies by using biotinylated recombinant proteins and to clarify the clinical and other serological features of DM patients with these antibodies.
Sera from 202 Japanese patients with CTDs, including 108 with DM and 20 healthy controls, were screened for anti-TIF1-α antibodies by our novel ELISAs. Positive sera were further examined by immunoprecipitation and also investigated for the detection of anti-TIF1-γ and anti-Mi-2 antibodies.
Sera from 12 patients with DM were confirmed to be positive for anti-TIF1-α antibodies. None of the patients with other CTDs and none of the healthy controls had the antibodies. Seven anti-TIF1-α-positive patients simultaneously had anti-TIF1-γ antibodies and the other five had anti-Mi-2 antibodies, both of which are well known to be MSAs. These double-positive patients with anti-TIF1-α and anti-γ antibodies included three JDM and two cancer-associated adult DM patients, whereas all the double-positive patients with anti-TIF1-α and anti-Mi-2 antibodies were classical adult DM.
Although MSAs have been regarded as mutually exclusive, anti-Mi-2 antibody-positive patients simultaneously have anti-TIF1-α antibodies. Anti-Mi-2 antibody-positive patients are associated with classical DM without cancer even with the simultaneous presence of anti-TIF1-α antibodies.
肌炎特异性自身抗体（MSAs）可用于诊断和预测皮肌炎/多肌炎（DM/PM）的预后，其可表征某些形式的炎性肌病。最近有报道称，抗转录中介因子1-α（TIF1-α）抗体与抗TIF1-γ抗体一起与癌症相关的DM有关。本研究旨在通过使用生物素化重组蛋白鉴定出具有抗TIF1-α抗体的DM患者亚组，并阐明具有这些抗体的DM患者的临床及其他血清学特征。
采用我们新的酶联免疫吸附测定（ELISA）法，对202例日本结缔组织病（CTD）患者（包括108例DM患者）的血清以及20例健康对照者的血清进行抗TIF1-α抗体筛查。对阳性血清进一步进行免疫沉淀检测，并检测抗TIF1-γ和抗Mi-2抗体。
12例DM患者的血清被确认为抗TIF1-α抗体阳性。其他CTD患者及健康对照者均无此抗体。7例抗TIF1-α阳性患者同时具有抗TIF1-γ抗体，另外5例具有抗Mi-2抗体，这两种抗体均为众所周知的MSAs。这些抗TIF1-α和抗γ抗体双阳性患者包括3例幼年皮肌炎（JDM）和2例癌症相关的成年DM患者，而所有抗TIF1-α和抗Mi-2抗体双阳性患者均为典型的成年DM。
尽管MSAs被认为是相互排斥的，但抗Mi-2抗体阳性患者同时具有抗TIF1-α抗体。即使同时存在抗TIF1-α抗体，抗Mi-2抗体阳性患者也与无癌症的典型DM相关。
