Employing this brand-new antibody, De Rycke em et al. antibody, and PAD4 as discovered with SN823 antibody. Primary magnification, 250. ar3702-S2.PPT (997K) GUID:?E58D556C-7FBC-44F6-BFD7-7802CFAFDA4E Abstract Launch Protein citrullination exists in the rheumatoid synovium, adding to the perpetuation of chronic inflammation presumably, in the current presence of specific autoimmunity. As a result, the present study examined the possibility that effective antirheumatic treatment will decrease the level of synovial citrullination. Methods Synovial biopsies were obtained from 11 rheumatoid arthritis (RA) patients before and after 8 weeks of treatment with 20 mg methotrexate weekly, 15 RA patients before and 2 weeks after an intraarticular glucocorticoid injection, and eight healthy volunteers. Synovial inflammation was assessed with double-blind semiquantitative analysis of lining thickness, cell infiltration, and vascularity by using a 4-point scale. Expression of citrullinated proteins (CPs) with the monoclonal antibody F95 and peptidylarginine deiminase (PAD) 2 and 4 was assessed immunohistochemically with double-blind semiquantitative analysis. em In vitro /em synovial fluid (SF), peripheral blood (PB), mononuclear cells (MCs), and synovial explants obtained from RA patients were incubated with dexamethasone and analyzed with immunohistochemistry for expression of CP as well as PAD2 and PAD4 enzymes. Results The presence of synovial CP was almost unique in RA compared with healthy synovium and correlated with the degree of local inflammation. Treatment with glucocorticoids but not methotrexate alters expression of synovial CP and PAD enzymes, in parallel with EB 47 a decrease of synovial inflammation. em Ex lover vivo /em and em in vitro /em studies suggest also a direct effect of glucocorticoids on citrullination, as exhibited by the decrease in the level of citrullination and PAD expression after incubation of SFMC and synovial explants with dexamethasone. Conclusion Synovial citrullination and PAD expression are dependent on local inflammation and targeted by glucocorticoids. Introduction Rheumatoid arthritis (RA) is usually a chronic inflammatory disease characterized by the presence of highly specific anti-citrullinated protein antibodies (ACPAs) [1]. These antibodies identify several different proteins that are citrullinated. Citrullination is the conversion of peptidylarginine to peptidylcitrulline through a calcium-dependent process catalyzed by the peptidylarginine deiminase (PAD) enzymes. Five PAD isotypes have been described in humans (PAD1, PAD2, PAD3, PAD4, and PAD6), which are expressed in a variety of tissues, but only PAD2 and PAD4 have been found to be expressed in inflamed synovial tissue of RA and other inflammatory arthritides [2]. Despite the high specificity of ACPA in RA in comparison to other arthritides and other inflammatory diseases [3], the presence of CP is not restricted to RA synovial tissue [4,5], but rather associated with inflammation in general [6]. Synovial citrullination appears therefore not to be essential for the predisease phase of induction of specific anti-citrulline immunity. Conversely, protein citrullination enhances the HLA binding capacity of synovial-derived proteins and promotes NF-B and tumor necrosis factor (TNF) production in the presence ACPA [7]. This suggests that local synovial citrullination might be essential in a later phase of the disease process, contributing to occurrence and perpetuation of chronic synovitis in the presence of specific anti-citrulline antibodies. It is therefore conceivable that downregulation of synovial citrullination by any means will contribute to the resolution of local inflammation. We hypothesize that effective antirheumatic treatment with either antiinflammatory, intraarticular glucocorticoids (GCs), or a disease-modifying antirheumatic drug, such as methotrexate (MTX) will decrease synovial citrullination em in vivo /em . As a result, the present study aimed to investigate any direct effect of these drugs on protein citrullination. Materials and methods Patients Twenty-six patients meeting the 1987 American College of Rheumatology criteria for RA [8] were recruited for this study. In a first group, 11 patients (six women and five men; median age, 56 years; range, 33 to 78 years) with newly diagnosed RA (symptom duration less than 1 year) previously disease-modifying antirheumatic drug (DMARD) na?ve were started on MTX, 10 mg weekly, and reached a stable dose of 20 mg after 2 weeks, increasing the dose EB 47 with 5 mg every week. Synovial biopsy samples were obtained by EB 47 arthroscopy from all patients before and after a median of 8 weeks of treatment. Clinical evaluation of the therapeutic response according to EULAR response criteria was performed EB 47 a RUNX2 median of 3 months after methotrexate initiation. In a second group, 15 RA patients (11 women and four men; median age, 63 years; range, 34 to 83 years) with active knee arthritis impartial of disease period received an intraarticular injection of 40 mg of.
