From undifferentiated arthritis to rheumatoid arthritis : epidemiology, immunology and early intervention

Abstract

In this thesis clinical and immunological studies in patients with undifferentiated (UA) and rheumatoid arthritis (RA) are described. Depending on the study population 6-55% of the patients who presented with UA actually fulfilled the criteria for RA as defined by the ACR in 1987 over time. In the first four years, radiographic joint damage, disease activity and HAQ were comparable in patients with RA presenting with UA and patients presenting with RA. Treatment of UA patients with methotrexate resulted in postponing progression to RA and retarding radiographic joint damage. In UA patients who had low/intermediate pretreatment ACPA-levels and were treated with methotrexate, the incidence of RA was lower than in patients with high levels. The disease activity score that was used in RA patients was validated in patients with UA. To identify which patient with UA will progress to RA, a prediction rule was developed. In patients with RA, treatment with TNF-alpha resulted in recovery of regulatory T cells. The importance of these regulatory T cells was emphasized in the strength of the anti-inflammatory response to the human cartilage glycoprotein 39 in healthy individuals: it even suppressed other pro-inflammatory responses, whereas patients with RA reacted with a pro-inflammatory response