German Centre for Pediatric and Adolescent Rheumatology (GCPAR), Gehfeldstrasse 24, 82467, Garmisch-Partenkirchen, Germany.
Department of Medical Imaging, University of Toronto, Toronto, Canada.
Pediatr Rheumatol Online J. 2022 Aug 13;20(1):66. doi: 10.1186/s12969-022-00721-7.
Unlike in adult rheumatology, for most forms of juvenile idiopathic arthritis (JIA) no reliable biomarkers currently exist to assess joint and disease activity. However, electrophoresis is frequently found changed in active juvenile arthritis. The objective of this study was to evaluate the α2-fraction of serum electrophoresis and its main components as biomarkers for JIA, categories extended/persistent oligoarthritis and seronegative polyarthritis, in comparison with the conventionally used erythrocyte sedimentation rate and C-reactive protein.
Serum samples and clinical data from 181 patients with JIA were collected. Serum electrophoresis and α2-fraction and its components were determined using standard methods. Relationship between calculated α2-fraction of serum electrophoresis (CA2F) and its components, acute-phase parameters and cJADAS27 was assessed using Pearson's correlation coefficient and linear regression modelling, adjusting for confounding effects. Results were confirmed in a second cohort with 223 serum samples from 37 patients, using a mixed model to account for repeated measures.
Compared to ESR and CRP, CA2F showed higher correlation to cJADAS27, in particular for persistent oligoarthritis. Of the three components of the α2-fraction, haptoglobin showed the highest correlation to cJADAS27. Regression analysis demonstrated higher ability to predict cJADAS27 for CA2F, and especially for haptoglobin as a component thereof, than for CRP and ESR.
Compared to conventional methods, α2-fraction of serum electrophoresis and specifically, haptoglobin show higher correlations with disease activity in common subtypes of JIA, representing excellent candidates as biomarkers for disease activity. Further studies are necessary to determine diagnostic value and correlations in other subtypes.
与成人风湿病不同，对于大多数形式的幼年特发性关节炎（JIA），目前尚无可靠的生物标志物来评估关节和疾病活动。然而，电泳在活动性幼年关节炎中经常发现改变。本研究的目的是评估血清电泳的α2 馏分及其主要成分作为 JIA、扩展/持续寡关节炎和血清阴性多关节炎类别的生物标志物，与常规使用的红细胞沉降率和 C 反应蛋白进行比较。
收集了 181 例 JIA 患者的血清样本和临床数据。使用标准方法测定血清电泳和α2 馏分及其成分。使用 Pearson 相关系数和线性回归模型评估计算的血清电泳α2 馏分（CA2F）与其成分、急性期参数和 cJADAS27 之间的关系，同时调整混杂效应。使用混合模型来解释重复测量，在第二个包含 37 例患者的 223 个血清样本的队列中验证了结果。
与 ESR 和 CRP 相比，CA2F 与 cJADAS27 的相关性更高，尤其是对于持续性寡关节炎。在α2 馏分的三个成分中，触珠蛋白与 cJADAS27 的相关性最高。回归分析表明，CA2F 预测 cJADAS27 的能力高于 CRP 和 ESR，尤其是作为其成分之一的触珠蛋白。
与传统方法相比，血清电泳的α2 馏分，特别是触珠蛋白，与 JIA 的常见亚型的疾病活动相关性更高，是疾病活动的生物标志物的良好候选物。需要进一步研究来确定在其他亚型中的诊断价值和相关性。
