Objective

Anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are useful for identifying a clinical subset of patients with idiopathic inflammatory myopathies (IIMs). Anti-OJ antibodies, which recognize multi-enzyme synthetase complexes including isoleucyl-tRNA synthetase (IARS) and lysyl-tRNA synthetase (KARS), are among the anti-ARS antibodies. Although testing antibodies to other ARSs have been used clinically, no validated immunoassays for detecting anti-OJ antibodies are available. We aimed to establish an anti-OJ ELISA.

Methods

Serum samples were collected from 279 patients with IIMs and 22 patients with idiopathic interstitial pneumonia. Sixty-four of the samples that had been confirmed to be negative for anti-OJ by standard immunoprecipitation were used as the negative control, and 12 anti-OJ-positive reference sera were used as the positive control. Antibodies to IARS and KARS were assayed by ELISA using biotinylated recombinant proteins generated by in vitro transcription/translation.

Results

The anti-OJ-positive sera strongly reacted with the KARS and IARS recombinant proteins in ELISA. Although all 12 reference sera were positive in the anti-KARS ELISA, 4 of the 64 anti-OJ-negative sera were also weakly positive. The sensitivity and the specificity were 100% and 93.8%, respectively. Since our anti-KARS ELISA performed well, showing a high agreement with the results for immunoprecipitation (Cohen's κ > 0.8), the remaining 237 samples were also tested. Thirteen anti-KARS-positive sera were newly found by ELISA, all of which were anti-OJ positive by immunoprecipitation.

Conclusion

Immunoassays for detecting anti-OJ antibodies using KARS and IARS recombinant proteins were developed. Our ELISAs performed well, with very high agreement of the results by immunoprecipitation and can be applied to the first reliable, easy-to-use measurement assays for anti-OJ antibodies.

中文翻译：

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抗 OJ 抗体阳性血清对赖氨酰-tRNA 合成酶和异亮氨酰-tRNA 合成酶的免疫识别

客观的

抗氨酰-tRNA合成酶（抗ARS）抗体可用于鉴定患有特发性炎性肌病（IIM）的患者的临床亚组。抗-OJ 抗体可识别多酶合成酶复合物，包括异亮氨酰-tRNA 合成酶 (IARS) 和赖氨酰-tRNA 合成酶 (KARS)，属于抗 ARS 抗体。尽管已在临床上使用检测其他 ARS 的抗体，但尚无用于检测抗OJ 抗体的有效免疫测定法。我们旨在建立抗-OJ ELISA。

方法

从 279 名 IIM 患者和 22 名特发性间质性肺炎患者中收集血清样本。以标准免疫沉淀法证实抗-OJ阴性的64份样品作为阴性对照，12份抗-OJ阳性参考血清作为阳性对照。使用通过体外转录/翻译产生的生物素化重组蛋白通过ELISA测定IARS和KARS抗体。

结果

在ELISA中，抗-OJ阳性血清与KARS和IARS重组蛋白发生强烈反应。尽管在抗-KARS ELISA中所有12个参考血清均为阳性，但64个抗-OJ-阴性血清中的4个也呈弱阳性。敏感性和特异性分别为100%和93.8%。由于我们的抗-KARS ELISA 表现良好，与免疫沉淀结果高度一致（Cohen's κ > 0.8），因此还测试了剩余的 237 个样本。ELISA新发现13份抗-KARS阳性血清，免疫沉淀均为抗-OJ阳性。

结论

开发了使用 KARS 和 IARS 重组蛋白检测抗OJ 抗体的免疫测定法。我们的 ELISA 表现良好，免疫沉淀结果的一致性非常高，可应用于第一个可靠、易于使用的抗OJ 抗体测量分析。