Strong inflammation is essential for expression of articular cartilage-specific citrullinated antigens / 南方医科大学学报

OBJECTIVE@#To investigate the expression of citrullinated epitopes in articular cartilage protein and whether its expression is sufficient to induce anti-citrullinated protein antibody (ACPA) response in mice.@*METHODS@#The experimental group was treated with different concentrations of lipopolysaccharide (LPS), heat-inactivated bacteria ( and ) or specific monoclonal antibody against type Ⅱ collagen to induce citrullination of articular cartilage protein, with PBS as the control. Immunohistochemistry with the monoclonal antibody ACC4 (IgG1) that specifically binds to the citrullinated epitope of cartilage protein was performed for detecting the expression of citrullinated protein, with ACC1 (IgG2a) as a positive control antibody and L243 (IgG2a) and Hy2.15 (IgG1) as the negative isotype control. In the in vivo experiment, SD rats were subjected to injection of different doses of LPS in the right knee (with PBS as the controls in the left knee), and 3 days later frozen sections were prepared for immunohistochemical detection of the expression of citrullinated protein. Models of collagen-induced arthritis (CIA) established in different mouse strains were observed for incidence and severity of CIA. Serum samples collected from these models and the sera from rheumatoid arthritis patients were examined for anti-citrullinated protein antibody, and immunohistochemistry was performed to detect the expression of citrullinated protein in the cartilage of the mouse.@*RESULTS@#The citrullinated CII epitope-specific antibody ACC4 did not bind to articular cartilage tissues with different treatments as compared with the positive control antibody ACC1. The ACC4 antibody and the antibodies from patients with rheumatoid arthritis with high titers of anti-citrullinated protein antibody were capable of binding to the synovial tissue around the articular cartilage of the CIA. Luminex analysis showed that the anti-citrullinated protein antibody was lowly expressed in mouse serum, but the anti-type Ⅱ collagen triple helix structure peptide antibody exhibited strong reactivity.@*CONCLUSIONS@#Mild acute inflammatory response is not enough to cause citrullination of articular cartilage protein, and the expression of specific epitope requires a high-intensity inflammatory response. Inflammatory articular cartilage protein can express citrullinated epitopes in type Ⅱ collagen-induced arthritis in mice, but the expression of citrullinated epitopes is not sufficient to induce an immune response to anti-citrullinated antibodies. Stronger stimulation signals are required to induce an immune response for producing anti-citrullinated protein antibodies.

Efficacy of a mouthwash containing essential oils and curcumin as an adjunct to nonsurgical periodontal therapy among rheumatoid arthritis patients with chronic periodontitis: A randomized controlled trial

Purpose: The purpose of this study was to assess the efficacy of mouthwash containing essential oils and curcumin (MEC) as an adjunct to nonsurgical periodontal therapy on the disease activity of rheumatoid arthritis (RA) among RA patients with chronic periodontitis (CP). Materials and Methods: A triple-blinded controlled trial was conducted among 45 female RA patients with CP randomized into three treatment groups as follows: Group A: scaling and root planing (SRP) with 0.2% chlorhexidine mouthwash as an adjunct (n = 15), Group B: SRP with MEC as an adjunct (n = 15), and Group C: SRP alone (n = 15). RA disease activity was assessed using erythrocyte sedimentation rate, serum C-reactive protein, serum anti-citrullinated protein antibody, and serum rheumatoid factor. Periodontal disease activity was assessed using plaque index, clinical attachment level (CAL), and pocket depth (PD). All parameters were recorded at baseline and 6 weeks thereafter. Data were assessed using one-way ANOVA and paired t-test. Results: A significant reduction in periodontal and RA disease activity parameters was observed from baseline to 6 weeks following intervention (P < 0.05). The highest percentage of mean reduction in plaque index and RA parameters from baseline to 6 weeks was observed in Group B followed by Groups A and C. The highest percentage of mean reduction in PD and CAL was observed in Group A followed by Groups B and C (P < 0.001). Conclusion: This study reveals that MEC as an adjunct to SRP is effective in reducing the disease activity of RA and CP, thereby warranting the use of the same.