Proteolysis by Granzyme B Enhances Presentation of Autoantigenic Peptidylarginine Deiminase 4 Epitopes in Rheumatoid Arthritis.

Proteolysis of autoantigens can alter normal MHC class II antigen processing and has been implicated in the induction of autoimmune diseases. Many autoantigens are substrates for the protease granzyme B (GrB), but the mechanistic significance of this association is unknown. Peptidylarginine deiminase 4 (PAD4) is a frequent target of autoantibodies in patients with rheumatoid arthritis (RA) and a substrate for GrB. RA is strongly associated with specific MHC class II alleles, and elevated levels of GrB and PAD4 are found in the joints of RA patients, suggesting that GrB may alter the presentation of PAD4 by RA-associated class II alleles. In this study, complementary proteomic and immunologic approaches were utilized to define the effects of GrB cleavage on the structure, processing, and immunogenicity of PAD4. Hydrogen-deuterium exchange and a cell-free MHC class II antigen processing system revealed that proteolysis of PAD4 by GrB induced discrete structural changes in PAD4 that promoted enhanced presentation of several immunogenic peptides capable of stimulating PAD4-specific CD4+ T cells from patients with RA. This work demonstrates the existence of PAD4-specific T cells in patients with RA and supports a mechanistic role for GrB in enhancing the presentation of autoantigenic CD4+ T cell epitopes.

Lack of association of oral calcium supplementation with coronary artery calcification in rheumatoid arthritis.

OBJECTIVE: To investigate the association between oral calcium supplementation and coronary artery calcification among rheumatoid arthritis (RA) patients without known cardiovascular disease (CVD). METHODS: This study was conducted as a nested, prospective cohort study of RA patients without known CVD. The daily supplemental calcium dose was ascertained from each patients' list of prescription and over-the-counter medications at baseline and at visit 2 (median 20 months postbaseline). The coronary artery calcium (CAC) score, a measure of coronary atherosclerosis, was assessed by cardiac multidetector row computed tomography at baseline and at visit 3 (median 39 months postbaseline). The association between calcium supplementation and CAC was explored. RESULTS: Among the 145 RA patients studied, 42 (28%) were taking ≥1,000 mg/day of supplemental calcium at baseline. A CAC score of >100 units was seen in 44 patients (30%) at baseline and 50 patients (34%) at followup. Baseline CAC scores of >100 units were significantly less frequent in patients receiving the higher dosage (≥1,000 mg/day) of supplemental calcium than in those receiving the lower dosage (<1,000 mg/day) (odds ratio [OR] 0.28, 95% confidence interval [95% CI] 0.11-0.74); this association remained significant after adjustment for relevant confounders (adjusted OR 0.30, 95% CI 0.09-0.93). Similarly, at the third study visit, CAC scores of >100 units were less frequent in the higher supplemental calcium dose group compared to the lower dose group (OR 0.41, 95% CI 0.18-0.95); however, after adjustment for relevant confounders, the statistical significance of this association was lost (adjusted OR 0.39, 95% CI 0.14-1.12). No effect of sex heterogeneity was seen in the association of calcium supplementation with coronary artery calcification, and no change in the CAC score over time was observed. CONCLUSION: Higher levels of oral calcium supplementation were not associated with an increased risk of coronary atherosclerosis, as measured by the CAC score, in this RA cohort.

A dual-center randomized controlled double blind trial assessing the effect of acupuncture in reducing musculoskeletal symptoms in breast cancer patients taking aromatase inhibitors.

Up to 50 % of women receiving aromatase inhibitor (AI) complain of AI-associated musculoskeletal symptoms (AIMSS) and 15 % discontinue treatment. We conducted a randomized, sham-controlled trial to evaluate whether acupuncture improves AIMSS and to explore potential mechanisms. Postmenopausal women with early stage breast cancer, experiencing AIMSS were randomized to eight weekly real or sham acupuncture sessions. We evaluated changes in the Health Assessment Questionnaire Disability Index (HAQ-DI) and pain visual analog scale (VAS) following the intervention compared to baseline. Serum estradiol, ß-endorphin, and proinflammatory cytokine concentrations were measured pre and post-intervention. We enrolled 51 women of whom 47 were evaluable, including 23 randomized to real and 24 to sham acupuncture. Baseline characteristics were balanced between groups with the exception of a higher HAQ-DI score in the real acupuncture group (p = 0.047). We did not observe a statistically significant difference in reduction of HAQ-DI (p = 0.30) or VAS (p = 0.31) between the two groups. Following eight weekly treatments, we observed a statistically significant reduction of IL-17 (p ≤ 0.009) in both groups. No significant modulation was seen in estradiol, ß-endorphin, or other proinflammatory cytokine concentrations in either group. We did not observe a significant difference in AIMSS changes between real and sham acupuncture. As sham acupuncture used in this study may not be equivalent to placebo, further studies with a non-acupuncture arm may be required to establish whether acupuncture is beneficial for the treatment of AIMSS.

Serious infections associated with anticytokine therapies in the rheumatic diseases.

The ability to target and neutralize macrophage-derived inflammatory cytokines, particularly tumor necrosis factor-alpha (TNF-alpha), has emerged in recent years as one of the most important advances in the treatment of rheumatoid arthritis, Crohn's disease, and several other systemic inflammatory diseases. In rheumatoid arthritis, for example, these biological agents rapidly reduce signs and symptoms of joint inflammation and profoundly slow the progression of joint damage. However, data that have emerged following Food and Drug Administration approval of these agents have alerted clinicians to an increased likelihood of opportunistic infections in patients treated with these agents, particularly tuberculosis. The effect of TNF inhibition on the frequency of infection with more common bacterial pathogens is less clear. Animal models of tuberculosis and other opportunistic infections have demonstrated the importance of TNF-alpha in controlling and containing intracellular pathogens. The spectrum of infections reported to date in the setting of anti-TNF-alpha treatment is reviewed here. In addition, relevant animal data illustrating potential mechanistic roles for TNF-alpha in host responses to infection are also reviewed.