| Since September 2004 patients without arthritis (mostly patients with joint complaints, some asymptomatic persons, further referred to as arthralgia patients) but with autoantibodies (IgM-RF and/or anti-CCP) present in the blood, are being prospectively followed in a project on the primary prevention of rheumatoid arthritis (RA, see above). Those patients not included in the trial are also followed prospectively; totaling 210 patients as of January 2008 (mean follow-up 16 months). 29 of these 210 patients have already developed arthritis. The current project beholds the expansion of this unique cohort to more than 400 patients and the enclosed lab work. The goal of this project is to develop a prediction rule to accurately assess the risk of the development of RA in these patients, thereby providing a basis for the selection of arthralgia patients for future intervention studies. Furthermore, there is a need to confirm preliminary results of the preparatory work, such as determining the contribution of the major risk factor for RA located on the HLA-DRB1 gene (the shared epitope, SE) and analysing RNA expression profiles in these arthralgia patients. Preliminary results show a higher frequency of the HLA shared epitope in arthralgia patients than in the general population, but lower than in RA patients. Moreover, the RNA-expression profile in a subset of the arthralgia patients shows remarkable similarities to RA patients. At the end of the study period, those arthralgia patients without arthritis will be compared to an estimated 50 arthralgia patients who have developed arthritis. A prediction rule can then be developed on the basis of clinical characteristics, imaging techniques, autoantibody profile, acute phase reactants and the genetic risk profile. This will enable us to further quantify the risk of RA in arthralgia patients. This may provide a basis for future intervention strategies, with the ultimate goal of the primary prevention of RA. |
