Research progress on serological indices and their clinical application in rheumatoid arthritis

BACKGROUND: As a chronic systemic autoimmune disease of undetermined etiology, rheumatoid arthritis (RA) has a complex pathogenesis, which involves multiple proteins and cytokines. The 2010 ACR/EULAR classification criteria facilitate early diagnosis of RA with reduced specificity when compared to the 1987 ACR criteria. Hence, it is imperative to identify novel serological inflammatory indicators and targets, in order to explain the complex regulatory network of RA. The present review discusses the associations of various inflammatory factors with RA and its underlying mechanism. Besides, the review also provides a novel insight into the clinical treatment of RA. MATERIALS AND METHODS: According to the PRISMA guidelines, databases like Web of Science, Google‐Scholar, Pubmed and Scopus were systematically searched for articles from January 1, 2018 to January 1, 2022 using The following 2 keywords: "rheumatoid arthritis", "Inflammatory cytokines", "ILs", "serum amyloid protein A", "matrix metalloproteinase 3", "RANKL", "Glucose‐6‐phosphoisomerase", "Anti‐keratin antibody", "1,25‐Dihydroxyvitamin D3". RESULTS: Indicators like MMPs, ILs, glucose‐6‐phosphate isomerase (GPI), anti‐keratin antibody (AKA) and receptor activator of nuclear factor‐κB ligand (RANKL) are the current hotspots in the efficacy research of RA. The present review suggests that ILs are highly expressed in the serum and synovial tissues of RA patients. By targeted inhibition of ILs with inhibitor application, precise RA treatment can be achieved. CONCLUSIONS: Based on these results, it can be concluded that inflammatory factors have certain guiding significance in the diagnosis and efficacy evaluation of RA. However, the mechanisms of interactions among them are rather complex, which deserve further exploration.