Clinical implications of seropositive and seronegative autoantibody status in rheumatoid arthritis patients: A comparative multicentre observational study

Rheumatoid factor (RF) and anti-cyclic citrullinated protein (anti-CCP) have been used to improve the diagnosis and prognosis of rheumatoid arthritis (RA). However, their association with RA disease phenotypes, individually and in combination, is not well studied. The aim of the study was to compare patients' and disease characteristics, activity and severity in double seronegative (DNRA), single seropositive RF, single seropositive anti-CCP and double seropositive (DPRA) patients.