Introduction. Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease that is often classified according to the presence of anti-cyclic citrullinated peptide antibodies (ACPA) and/or rheumatoid factor (RF) into seropositive or seronegative RA. RF and/or ACPA can be found in up to 75% of RA patients, and seropositivity may indicate higher disease activity and poorer […]
