Biomarkers in Rheumatoid Arthritis, what is new?

Rheumatoid arthritis (RA) is a chronic inflammatory disease with autoimmune pathogenesis. It affects mainly small joints (of the hands and feet) and has many systemic manifestations. Studying biomarkers in rheumatology intensely appeared from the need to understand the mechanisms underlying some rheumatic diseases. Discovering new biomarkers with key roles in various stages of evolution, remains a subject of interest for RA. Currently, according to the EULAR 2010 criteria, the rheumatoid factor (RF) and the anti-cyclic citrullinated peptide (anti-CCP) are used for RA diagnosis. Since 2010, new biomarkers were discovered and proved useful in identifying RA in early stages. For a more rigorous management of these cases, one of the key steps in the evolution of patients with RA is to recognize and distinguish the more aggressive forms of the disease through prognostic biomarkers. "Treat to target" recommends the use of 3 composite scores to monitor the evolution of the disease: disease activity score (DAS 28), simple disease activity index (SDAI) and clinical disease activity index (CDAI), but, a new test was developed which better monitors the disease activity. The introduction of biological therapies has revolutionized the treatment of RA. Despite these advances, 20-40% of the patients are declared nonresponders to at least one of the therapies. The patient exposure to the potential side effects and high costs requires the discovery of a biomarker that could identify those who can benefit from the pretreatment of a certain therapy.

Abbreviations: RA = rheumatoid arthritis, RF = rheumatoid factor, DAS 28 = disease activity score, SDAI = simple disease activity index, CDAI = clinical disease activity index, ACR = American College of Rheumatology, EULAR = European League against Rheumatism, anti-CCP = antibodies against cyclic citrullinated proteins, anti-MCV = mutated citrullinated vimentin antibodies, anti-CarP = antibodies against carbamylated proteins, MBDA = multi biomarker disease activity test, COMP = cartilage oligomeric matrix protein, ADAs = antidrug antibodies, CDA = clinical disease activity index, SDAI = simplified disease activity index, ESR = erythrocyte sedimentation rate, CRP = C reactive protein, SAA = serum amyloid A, VCAM-1 = vascular cell adhesion molecule-1, IL-6 = interleukin-6, TNF-R1 = tumor necrosis factor receptor 1, EGF = epidermal growth factor, VEGF-A = vascular endothelial growth factor A.