OBJECTIVES Anti-TIF1γ autoantibodies are associated with malignancy in adult-onset idiopathic inflammatory myopathy (IIM) and this risk is attenuated if patients are also positive for anti-specificity protein 4 (Sp4) or anti-cell division cycle apoptosis regulator protein 1 (CCAR1). In anti-TIF1γ positive US dermatomyositis (DM) patients, anti-Sp4 and anti-CCAR1 autoantibody frequencies are reported as 32% and 43% in adults and 9% and 19% in juveniles, respectively. This study aims to identify the frequency of anti-Sp4 and anti-CCAR1 in adult and juvenile UK anti-TIF1ƴ-positive myositis populations and report clinical associations. METHODS Serum samples from 51 UK participants with adult-onset IIM and 55 UK participants with JDM, all anti-TIF1γ autoantibody positive, and 24 healthy control samples were screened for anti-Sp4 and anti-CCAR1 autoantibodies by ELISA. RESULTS In UK adult anti-TIF1γ positive IIM patients, anti-Sp4 and anti-CCAR1 frequencies were 4% (2/51) and 16% (8/51). Both adult patients with anti-Sp4 were also positive for anti-CCAR1. In UK juveniles, anti-Sp4 was not detected and 16% (7/55) had anti-CCAR1 autoantibodies. Nineteen (37%) anti-TIF1γ positive UK adult myositis patients had cancer; neither of the two patients with anti-Sp4 autoantibodies and 25% (2/8) of anti-CCAR1 autoantibody-positive patients had cancer. No anti-Sp4 or anti-CCAR1 clinical associations were identified. CONCLUSION Anti-Sp4 and anti-CCAR1 autoantibodies are less common in the adult UK anti-TIF1ƴ-positive myositis population compared with published US data, limiting their use as biomarkers for cancer risk. In patients with juvenile onset disease, anti-Sp4 is less frequent in UK patients compared with the US, but the prevalence of anti-CCAR1 autoantibodies is similar.

中文翻译：

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英国与美国成人和青少年发病的抗 TIF1ƴ 阳性肌炎患者的抗 Sp4 和抗 CCAR1 自身抗体。


目的 抗 TIF1γ 自身抗体与成人特发性炎症性肌病 （IIM） 的恶性肿瘤相关，如果患者抗特异性蛋白 4 （Sp4） 或抗细胞分裂周期凋亡调节蛋白 1 （CCAR1） 也呈阳性，则这种风险会降低。在抗 TIF1γ 阳性美国皮肌炎 （DM） 患者中，据报道，成人抗 Sp4 和抗 CCAR1 自身抗体的频率分别为 32% 和 43%，青少年的抗 9% 和 19%。本研究旨在确定英国成人和青少年抗 TIF1ƴ 阳性肌炎人群中抗 Sp4 和抗 CCAR1 的频率，并报告临床关联。方法 通过 ELISA 筛选来自 51 例英国成人发病 IIM 参与者和 55 例英国 JDM 参与者、所有抗 TIF1γ 自身抗体阳性和 24 例健康对照样本的血清样本抗 Sp4 和抗 CCAR1 自身抗体。结果 在英国成人抗 TIF1γ 阳性 IIM 患者中，抗 Sp4 和抗 CCAR1 频率分别为 4% （2/51） 和 16% （8/51）。两名成年抗 Sp4 患者也均抗 CCAR1 阳性。在英国青少年中，未检测到抗 Sp4,16% （7/55） 具有抗 CCAR1 自身抗体。19 例 （37%） 抗 TIF1γ 阳性英国成人肌炎患者患有癌症;2 例抗 Sp4 自身抗体患者和 25% （2/8） 的抗 CCAR1 自身抗体阳性患者均未患癌症。未发现抗 Sp4 或抗 CCAR1 临床关联。结论 与已发表的美国数据相比，抗 Sp4 和抗 CCAR1 自身抗体在英国成人抗 TIF1ƴ 阳性肌炎人群中不太常见，限制了它们作为癌症风险生物标志物的使用。在青少年发病患者中，与美国患者相比，英国患者的抗 Sp4 较少见，但抗 CCAR1 自身抗体的患病率相似。