A chronic autoimmune disease with inflammation of the joints and marked deformities; something (possibly a virus) triggers an attack on the synovium by the immune system, which releases cytokines that stimulate an inflammatory reaction that can lead to the destruction of all components of the joint WordNet 3.0 & Open English WordNet

Rheumatoid arthritis is a long-term autoimmune disorder that primarily affects joints. Wikipedia

A chronic, systemic inflammatory disorder that attacks synovial joints Wikipedia Disambiguation

An arthritis that is an autoimmune disease which attacks healthy cells and tissue located in joint. Wikidata

Inflammatory autoimmune disorder that causes the immune system to attack the joints. OmegaWiki

A chronic and progressive disease in which the immune system attacks the joints. It is characterised by pain, inflammation and swelling of the joints, stiffness, weakness, loss of mobility and deformity. Tissues throughout the body can be affected, including the skin, blood vessels, heart, lungs, and muscles. Wiktionary

Chronic and progressive disease. Wiktionary (translation)