PDF(Pubmed)
Abstract：
To investigate the reliability of elevated titres of antineutrophil cytoplasmic antibody (ANCA) and to identify a cut-off titre in discriminating between ANCA-associated vasculitides (AAV) and its mimickers.
This retrospective observational single-centre study included patients over 18 years with positive myeloperoxidase (MPO)-ANCA and/or proteinase 3 (PR3)-ANCA immunoassays over an 8-year period (January 2010 to December 2018), via their electronic medical files. Patients were classified according to the 2022 ACR/EULAR criteria and alternative diagnoses categorised either as non-AAV autoimmune disorders (ANCA-AI) or disorders without autoimmune features (ANCA-O). Findings from the AAV group were compared with those of ANCA-AI and ANCA-O groups and followed by a multivariate logistic stepwise regression analysis of features associated with AAV.
288 ANCA-positive patients of which 49 had AAV were altogether included. There was no difference between patients between the ANCA-AI (n=99) and the ANCA-O (n=140) groups. The AUC for titres discriminating AAV from mimickers was 0.83 (95% CI, 0.79 to 0.87). The best threshold titre, irrespective of PR3-ANCA or MPO-ANCA, was 65 U/mL with a negative predictive value of 0.98 (95% CI, 0.95 to 1.00). On multivariate analysis, an ANCA titre ≥65 U/mL was independently associated with AAV with an OR of 34.21 (95% CI 9.08 to 129.81; p<0.001). Other risk factors were: pulmonary fibrosis (OR, 11.55 (95% CI, 3.87 to 34.47, p<0.001)), typical ear nose and throat involvement (OR, 5.67 (95% CI, 1.64 to 19.67); p=0.006) and proteinuria (OR, 6.56 (95% CI, 2.56 to 16.81; p<0.001)).
High PR3/MPO-ANCA titres can help to discriminate between AAV and their mimickers in patients presenting with small-calibre vasculitides, with a threshold titre of 65 U/mL and above.
This retrospective observational single-centre study included patients over 18 years with positive myeloperoxidase (MPO)-ANCA and/or proteinase 3 (PR3)-ANCA immunoassays over an 8-year period (January 2010 to December 2018), via their electronic medical files. Patients were classified according to the 2022 ACR/EULAR criteria and alternative diagnoses categorised either as non-AAV autoimmune disorders (ANCA-AI) or disorders without autoimmune features (ANCA-O). Findings from the AAV group were compared with those of ANCA-AI and ANCA-O groups and followed by a multivariate logistic stepwise regression analysis of features associated with AAV.
288 ANCA-positive patients of which 49 had AAV were altogether included. There was no difference between patients between the ANCA-AI (n=99) and the ANCA-O (n=140) groups. The AUC for titres discriminating AAV from mimickers was 0.83 (95% CI, 0.79 to 0.87). The best threshold titre, irrespective of PR3-ANCA or MPO-ANCA, was 65 U/mL with a negative predictive value of 0.98 (95% CI, 0.95 to 1.00). On multivariate analysis, an ANCA titre ≥65 U/mL was independently associated with AAV with an OR of 34.21 (95% CI 9.08 to 129.81; p<0.001). Other risk factors were: pulmonary fibrosis (OR, 11.55 (95% CI, 3.87 to 34.47, p<0.001)), typical ear nose and throat involvement (OR, 5.67 (95% CI, 1.64 to 19.67); p=0.006) and proteinuria (OR, 6.56 (95% CI, 2.56 to 16.81; p<0.001)).
High PR3/MPO-ANCA titres can help to discriminate between AAV and their mimickers in patients presenting with small-calibre vasculitides, with a threshold titre of 65 U/mL and above.
摘要：
目的：研究抗中性粒细胞胞浆抗体（ANCA）滴度升高的可靠性，并确定区分ANCA相关血管炎（AAV）及其模拟物的截止滴度。
方法：这项回顾性观察性的单中心研究包括18岁以上的患者，在8年期间（2010年1月至2018年12月），髓过氧化物酶（MPO）-ANCA和/或蛋白酶3（PR3）-ANCA免疫测定阳性。通过他们的电子医疗档案.根据2022年ACR/EULAR标准对患者进行分类，替代诊断分为非AAV自身免疫性疾病（ANCA-AI）或无自身免疫特征的疾病（ANCA-O）。将AAV组的结果与ANCA-AI和ANCA-O组的结果进行比较，然后对与AAV相关的特征进行多变量逻辑逐步回归分析。
结果：共包括288例ANCA阳性患者，其中49例患有AAV。ANCA-AI（n=99）和ANCA-O（n=140）组之间的患者之间没有差异。区分AAV与模拟物的滴度的AUC为0.83(95%CI,0.79至0.87)。最佳阈值滴度，无论PR3-ANCA或MPO-ANCA，为65U/mL，阴性预测值为0.98（95%CI，0.95至1.00）。在多变量分析中，ANCA滴度≥65U/mL与AAV独立相关,OR为34.21(95%CI9.08~129.81;p<0.001).其他危险因素是：肺纤维化(OR，11.55（95%CI，3.87至34.47，p<0.001），典型的耳鼻喉受累（或，5.67（95%CI，1.64至19.67）；p=0.006）和蛋白尿（OR，6.56（95%CI，2.56至16.81；p<0.001））。
结论：高PR3/MPO-ANCA滴度有助于区分表现为小口径血管炎的患者的AAV及其模拟因子，阈值滴度为65U/mL及以上。
方法：这项回顾性观察性的单中心研究包括18岁以上的患者，在8年期间（2010年1月至2018年12月），髓过氧化物酶（MPO）-ANCA和/或蛋白酶3（PR3）-ANCA免疫测定阳性。通过他们的电子医疗档案.根据2022年ACR/EULAR标准对患者进行分类，替代诊断分为非AAV自身免疫性疾病（ANCA-AI）或无自身免疫特征的疾病（ANCA-O）。将AAV组的结果与ANCA-AI和ANCA-O组的结果进行比较，然后对与AAV相关的特征进行多变量逻辑逐步回归分析。
结果：共包括288例ANCA阳性患者，其中49例患有AAV。ANCA-AI（n=99）和ANCA-O（n=140）组之间的患者之间没有差异。区分AAV与模拟物的滴度的AUC为0.83(95%CI,0.79至0.87)。最佳阈值滴度，无论PR3-ANCA或MPO-ANCA，为65U/mL，阴性预测值为0.98（95%CI，0.95至1.00）。在多变量分析中，ANCA滴度≥65U/mL与AAV独立相关,OR为34.21(95%CI9.08~129.81;p<0.001).其他危险因素是：肺纤维化(OR，11.55（95%CI，3.87至34.47，p<0.001），典型的耳鼻喉受累（或，5.67（95%CI，1.64至19.67）；p=0.006）和蛋白尿（OR，6.56（95%CI，2.56至16.81；p<0.001））。
结论：高PR3/MPO-ANCA滴度有助于区分表现为小口径血管炎的患者的AAV及其模拟因子，阈值滴度为65U/mL及以上。
