BACKGROUND It is has been proposed that the presence of anti-DFS70 antibodies could be used to eliminate a SARD diagnosis. However, anti-DFS70 antibodies were also observed at relatively high frequency in patients with SARD. The clinical significance of these antibodies is therefore not yet clear. In this study, we assessed the clinical significance of the presence of anti-DFS70 antibodies. METHODS A total of 3432 sera samples were obtained from patients who underwent routinely requested ANA screening in the clinical laboratory of a University Hospital, between June 2017 and June 2019. Antinuclear antibody testing was performed by indirect immunofluorescence (IIF) on Hep-2 cell substrates (Euroimmun, Germany), and anti-ENA were measured by LIA (Euroimmun, Germany). RESULTS Among 3432 serum samples tested for ANA, 57.3% were ANA positive by IIF. Participants had mean age of 46.4 and 74.8% of the participants were female. Only 11.4% of the study population had SARD. The frequency of DFS pattern by IIF was 8.1%. Analysis of the DFS pattern positive samples by LIA revealed the presence of anti-DFS70 autoantibodies in 67.5% of all DFS, AC-2 pattern ANAs. When using the results of the ANA IIF HEp-2 DFS pattern/Anti-DFS70 LIA, likelihood ratio (LR) for SARD was 0.33. When comparing the ANA IIF HEp-2 DFS pattern with anti-DFS70 LIA, the ANA IIF HEp-2 DFS pattern's LR was lower (0.63 vs 0.85). CONCLUSIONS Although the DFS pattern cannot exclude the presence of SARD, the likelihood is lower than with other patterns. Therefore, anti-DFS70 antibodies represent an important biomarker that can aid in the interpretation of positive ANA patients and, therefore, should be included in test algorithms for ANA testing. The optimal test algorithm might be laboratory specific being dependent on referral patterns for ANA testing.

中文翻译：

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抗DFS70抗体在接受常规抗核抗体测试的一组患者中的临床价值。

背景技术已经提出抗DFS70抗体的存在可以用于消除SARD诊断。但是，在SARD患者中也以相对较高的频率观察到了抗DFS70抗体。因此，这些抗体的临床意义尚不清楚。在这项研究中，我们评估了抗DFS70抗体的临床意义。方法于2017年6月至2019年6月之间，从大学医院临床实验室常规接受ANA筛查的患者中获得了3432份血清样品。通过间接免疫荧光（IIF）对Hep-2细胞底物进行了抗核抗体测试（Euroimmun，德国）和抗ENA由LIA（Euroimmun，德国）测量。结果在3432份ANA血清样品中，IIF检测出ANA阳性率为57.3％。参加者的平均年龄为46.4岁，其中74.8％为女性。只有11.4％的研究人群患有SARD。IIF的DFS模式频率为8.1％。LIA对DFS模式阳性样本的分析显示，在所有DFS，AC-2模式ANA中有67.5％存在抗DFS70自身抗体。使用ANA IIF HEp-2 DFS模式/ Anti-DFS70 LIA的结果时，SARD的似然比（LR）为0.33。当将ANA IIF HEp-2 DFS模式与抗DFS70 LIA进行比较时，ANA IIF HEp-2 DFS模式的LR较低（0.63对0.85）。结论尽管DFS模式不能排除SARD的存在，但可能性比其他模式低。因此，抗DFS70抗体代表了重要的生物标志物，可帮助解释阳性ANA患者，因此，应该包含在ANA测试的测试算法中。最佳测试算法可能是特定于实验室的，具体取决于ANA测试的推荐模式。