Zeng Yanli, Lin Yiqiang, Wang Xuelian, Zhang Yan, Peng Feng, Wang JiaJia, Jiang Longcan, Liang Shiqiong, Xiao Yun
Center of Clinical Laboratory, Zhongshan Hospital, School of Medicine, Xiamen University, Xiamen, 361004, China.
Department of Obstetrics and Gynecology, Zhongshan Hospital of Xiamen University, Xiamen, 361004, China.
Clin Rheumatol. 2020 Sep;39(9):2619-2629. doi: 10.1007/s10067-020-05040-4. Epub 2020 Mar 18.
Our aim was to investigate the prevalence value of a high-avidity antinuclear antibody (ANA) of the IgG isotype (HA IgG ANA) compared with that of ANAs of other isotypes in patients with systemic lupus erythematosus (SLE) and to assess the associations of HA IgG ANA with the activity of SLE and lupus nephritis.
We retrospectively analyzed clinical and laboratory data from subjects. Blood samples were acquired from 101 SLE patients, 67 patients with other autoimmune diseases, and 65 healthy donors. The levels of HA IgG ANA and other isotype ANAs were measured by indirect immunofluorescence (IIF). The prevalence and diagnosis value of HA IgG ANA and other antibodies in SLE patient were tested. The advantage of HA IgG ANA compared with HA anti-dsDNA antibodies IgG (HA dsDNA IgG) was verified by ELISA. We monitored the relative avidity indexes (RAIs) of HA IgG ANA and HA dsDNA IgG at 3 time points after the start of treatment in the same individuals with SLE.
The prevalence of HA IgG ANA was significantly higher in active cases than in inactive cases of SLE and LN, which is consistent with data for IgG ANAs, anti-dsDNA IgG antibodies, low C3 levels, low C4 levels, and anti-C1q antibodies. HA IgG ANA showed moderate sensitivity and specificity (80% and 81.3%) for discriminating active and inactive SLE cases. However, HA IgG ANA showed no significant differences among the different clinical manifestations of SLE. Compared with that of HA dsDNA IgG, the RAI of HA IgG ANA was positively related to SLEDAI scores after treatment at 0, 1, and 3 months (r = 0.6813, p = 0.0026; r = 0.5972, p = 0.0114; r = 0.4817, p = 0.0474).
First, we demonstrated that HA IgG ANA was a reliable diagnostic tool in SLE patients. Furthermore, HA IgG ANA was supposed to be more appropriate for identifying the activity of SLE compared with HA dsDNA IgG. In summary, HA IgG ANA may be a new biomarker for diagnosing SLE and identifying SLE activity. Key Points • We first introduced the concept of a "high-avidity IgG ANA (HA IgG ANA)" that could distinguish between the early stage of SLE and SLE that had been active for some time. • The relative avidity indexes (RAIs) of HA IgG ANA and HA dsDNA IgG were presented and applied here to evaluate the avidities of antibodies involved in SLE. • In our study, we confirmed the value of HA IgG ANA in diagnosing SLE. In addition, HA IgG ANA was more appropriate for identifying the activity of SLE than was HA dsDNA IgG. • In conclusion, HA IgG ANA could be a potential biomarker for the assessment of the prognosis of SLE activity.
我们的目的是研究与其他同种型抗核抗体（ANA）相比，系统性红斑狼疮（SLE）患者中IgG同种型高亲和力抗核抗体（HA IgG ANA）的流行率，并评估HA IgG ANA与SLE活动及狼疮性肾炎的相关性。
我们回顾性分析了受试者的临床和实验室数据。采集了101例SLE患者、67例其他自身免疫性疾病患者和65名健康供者的血样。通过间接免疫荧光法（IIF）检测HA IgG ANA和其他同种型ANA的水平。检测HA IgG ANA和其他抗体在SLE患者中的流行率和诊断价值。通过酶联免疫吸附测定（ELISA）验证HA IgG ANA与HA抗双链DNA抗体IgG（HA dsDNA IgG）相比的优势。我们在同一组SLE患者治疗开始后的3个时间点监测HA IgG ANA和HA dsDNA IgG的相对亲和力指数（RAI）。
HA IgG ANA在SLE和狼疮性肾炎的活动期病例中的流行率显著高于非活动期病例，这与IgG ANA、抗双链DNA IgG抗体、低C3水平、低C4水平和抗C1q抗体的数据一致。HA IgG ANA在区分活动期和非活动期SLE病例方面显示出中等的敏感性和特异性（分别为80%和81.3%）。然而，HA IgG ANA在SLE的不同临床表现之间没有显著差异。与HA dsDNA IgG相比，HA IgG ANA的RAI在治疗后0、1和3个月与SLE疾病活动指数（SLEDAI）评分呈正相关（r = 0.6813，p = 0.0026；r = 0.5972，p = 0.0114；r = 0.4817，p = 0.0474）。
首先，我们证明HA IgG ANA是SLE患者可靠的诊断工具。此外，与HA dsDNA IgG相比，HA IgG ANA被认为更适合用于识别SLE的活动情况。总之，HA IgG ANA可能是诊断SLE和识别SLE活动的一种新生物标志物。要点 • 我们首次引入了“高亲和力IgG ANA（HA IgG ANA）”的概念，它可以区分SLE的早期阶段和已活动一段时间的SLE。 • 这里展示并应用了HA IgG ANA和HA dsDNA IgG的相对亲和力指数（RAI）来评估参与SLE的抗体的亲和力。 • 在我们的研究中，我们证实了HA IgG ANA在诊断SLE中的价值。此外，与HA dsDNA IgG相比，HA IgG ANA更适合识别SLE的活动情况。 • 总之，HA IgG ANA可能是评估SLE活动预后的潜在生物标志物。
