Prevention of seronegative rheumatoid arthritis: an entity of its own

In 1940, in his Oslo laboratory, Eric Waaler described rheumatoid factor—the first molecular marker identifying a subset of arthritis characterised by autoantibodies (ie, seropositive rheumatoid arthritis). This subset increased in size 60 years later with the discovery of anti-citrullinated protein antibody (ACPA). Instead of accepting that seropositive rheumatoid arthritis is different from seronegative rheumatoid arthritis, we stubbornly keep the unifying term rheumatoid arthritis, which mixes phenotypes that differ in origin, genetics, pathophysiology, and clinical course. With the TREAT EARLIER trial, Krijbolder and colleagues and Dumoulin and colleagues provide further evidence that combining seropositive and seronegative rheumatoid arthritis into a single disease might be a mistake.