Decreased Serum CTRP3 level was associated with connective tissue diseases.

Objective: Complement C1q tumor necrosis factor-related protein 3 (CTRP3) and 9 (CTRP9) are two of the most extensively studied adipokines, known for their diverse biological functions. However, it remains unclear whether serum levels of CTRP3 or CTRP9 are associated with connective tissue diseases (CTD). Methods: Serum CTRP3 and CTRP9 levels were measured by enzyme-linked immune sorbent assay (ELISA) and analyzed in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), primary Sjogren's syndrome (pSS), ankylosing spondylitis (AS), undifferentiated connective tissue disease (UCTD), as well as in healthy controls (HCs). Results: Serum CTRP3 levels were all significantly lower in patients with RA, SLE, pSS and AS compared with HCs. However, there were no significant differences in serum CTRP9 levels between patients with RA, SLE, pSS, or AS and HCs. In pSS patients, CTRP3 showed a weak correlation with blood glucose, creatinine, and urine acid in pSS patients, while no correlations were observed between serum CTRP3 levels and clinical or laboratory indices in RA, SLE or AS patients. Stable associations between CTRP3 and RA, SLE, pSS and AS were evaluated using multivariate logistics regression analysis. Receiver operating characteristic (ROC) curves were plotted to evaluated CTRP3 as a marker for RA, SLE, pSS and AS, yielding area under curve (AUC) values of 0.691, 0.727, 0.658 and 0.694, respectively. Conclusion: Decreased serum CTRP3 levels were associated with RA, SLE, pSS and AS.

Comparison of different assays for the detection of anticyclic citrullinated peptide antibodies in patients with rheumatoid arthritis.

Objective: To evaluate a novel fully automated immunoturbidimetric assay developed by Qiangsheng Biotechnology Company for the detection of anticyclic citrullinated peptide antibodies (anti-CCP) in serum of patients with rheumatoid arthritis (RA) and compare it to the conventional EUROIMMUN- anti-CCP ELISA. Two other commonly used automated assays, the Elecsys anti-CCP assay, an ECLIA that is run on the Modular Analystics E170 (Cobas Diagnostics, Germany), and an anti-CCP CLIA developed by YHLO that is run on the iFlash 3000 Chemiluminescence Immunoassay Analyzer, were included as reference standards. Methods: A total of 264 serum samples were collected from patients attending the First People's Hospital of Wenling affiliated to Wenzhou Medical University between July 2020 and November 2020. These included 131 serum samples collected from patients with RA, 70 serum samples collected from patients with other autoimmune diseases, and 63 serum samples collected from healthy controls at a physical examination. The clinical performance and sensitivity and specificity of the four anti-CCP assays for the diagnosis of RA were compared using receiver operating characteristic (ROC) curve analysis. Results: The Kappa statistic indicated almost perfect agreement between the EUROIMMUN-anti-CCP ELISA and the Elecsys anti-CCP ECLIA (Cobas) (0.863), the EUROIMMUN-anti-CCP ELISA and the anti-CCP CLIA (YHLO) (0.862), and the Elecsys anti-CCP ECLIA (Cobas) and the anti-CCP CLIA (YHLO) (0.816). On ROC curve analysis, AUC values were 0.955 for the EUROIMMUN-anti-CCP ELISA, 0.948 for the anti-CCP CLIA (YHLO), 0.947 for the Elecsys anti-CCP ECLIA (Cobas) and 0.903 for Qiangsheng, indicating all the assays had a good diagnostic performance for RA. Conclusion: The anti-CCP assays provided similar diagnostic information. The novel fully automated immunoturbidimetric assay for anti-CCP developed by Qiangsheng Biotechnology Company may be especially useful for large scale clinical screening in RA as it has a shorter testing time than the commercially available alternatives.