In this thesis two main aims were addressed. It has long been established that early treatment of rheumatoid arthritis (RA) improves disease outcomes. In Part I of this thesis we therefore further... Show moreIn this thesis two main aims were addressed. It has long been established that early treatment of rheumatoid arthritis (RA) improves disease outcomes. In Part I of this thesis we therefore further investigated the early detection of at-risk individuals by studying a large cohort of patients with clinically suspect arthralgia (CSA). We explored the value of two easy clinical tests, their potential to detect underlying inflammatory processes and to predict disease progression. In addition we investigated the presence of subclinical synovitis on imaging as starting point for treatment with disease modifying anti-rheumatic drugs (DMARDs) and the value of magnetic resonance imaging (MRI) detected erosions as new predictor for RA-development. In Part II of this thesis we aimed to determine which disease processes are involved in the different phases of RA-development. Knowledge on disease pathogenesis and timing of influencing factors can help to better target treatment during RA-development. We therefore evaluated whether autoantibody-response maturation occurred during the phase of CSA, and investigated the timing of genetic risk factor human leukocyte antigen-shared epitope (HLA-SE) and environmental risk factor smoking during the development of autoantibody-positive disease. Show less
Iwasaki, T.; Nakabo, S.; Terao, C.; Murakami, K.; Nakashima, R.; Hashimoto, M.; ... ; Ohmura, K. 2020
Background The anti-cyclic citrullinated peptide (CCP) antibody is a diagnostic biomarker of rheumatoid arthritis (RA). However, some non-RA connective tissue disease (CTD) patients also test... Show moreBackground The anti-cyclic citrullinated peptide (CCP) antibody is a diagnostic biomarker of rheumatoid arthritis (RA). However, some non-RA connective tissue disease (CTD) patients also test positive for the anti-CCP antibody and, thus, may ultimately develop RA. We retrospectively investigated whether anti-CCP-positive non-RA CTD patients developed RA and attempted to identify factors that may differentiate RA-overlapping CTD from pure CTD. Methods In total, 842 CTD patients with a primary diagnosis that was not RA were selected from our CTD database as of December 2012. Anti-CCP antibody titers were obtained from a retrospective chart review or measured using stored sera. RA was diagnosed according to the 1987 revised American College of Rheumatology classification criteria. Thirty-three anti-CCP-positive non-RA CTD patients were retrospectively followed up for the development of RA. Bone erosions on the hands and feet were assessed by X-ray. Citrullination dependency was evaluated by an in-house ELISA, the HLA-DRB1 allele was typed, and the results obtained were then compared between RA-overlapping and non-RA anti-CCP-positive CTD patients. Results Two out of 33 anti-CCP-positive CTD patients (6.1%) developed RA during a mean follow-up period of 8.9 years. X-rays were examined in 27 out of the 33 patients, and only one (3.7%) showed bone erosions. The frequency of the HLA-DRB1 shared epitope (SE) and anti-CCP antibody titers were both significantly higher in anti-CCP-positive RA-overlapping CTD patients than in anti-CCP-positive non-RA CTD patients, while no significant differences were observed in citrullination dependency. Conclusions Anti-CCP-positive non-RA CTD patients rarely developed RA. HLA-DRB1 SE and anti-CCP antibody titers may facilitate the differentiation of RA-overlapping CTD from anti-CCP-positive non-RA CTD. Show less
Rheumatoid arthritis (RA) is a chronic inflammation of several joints caused by autoimmunity. HLA molecules are most important risk factor involved in RA development. Regarding the risk of RA... Show moreRheumatoid arthritis (RA) is a chronic inflammation of several joints caused by autoimmunity. HLA molecules are most important risk factor involved in RA development. Regarding the risk of RA development, three variants can be discriminated; the shared epitope increases the risk, DERAA-containing HLA molecules decrease the risk and a neutral variant. In this thesis we describe that a mother, in contrast to a father, with a DERAA-containing HLA-molecule confers a life-long protection to her child against RA development with and without passing the gene responsible for the HLA-molecule. Furthermore, we describe that the T cells of HLA-DR4 positive RA patients can react against certain peptides derived from the citrullinated (a post-translational modification) vimentin protein in a citrulline-specific manner. Next to HLA-molecules there are several other genetic factors involved in the risk of RA development, e.g. PTPN22 and CD40. For the PTPN22 SNP associated with RA development, we showed that information on the presence of the PTPN22 SNP next to the presence of ACPA (antibodies specific for RA patients) does not give additive value to the prediction of RA development. On the contrary, the SNP has an influence on the level of ACPA present in the patient. For a SNP in the CD40 gene, we showed that it influences the severity and progression of RA. Show less
