Revisit of autoimmunity to glucose-6-phosphate isomerase in experimental and rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory disorder characterized by synovial inflammation in multiple joints. Autoantibodies (Abs) are the hallmark of RA, and as disease-specific and diagnostic markers, rheumatoid factor and anti-citrullinated protein antibody (ACPA) are produced pre-clinically, but their pathogenic roles in RA remain elusive. In this review, we focus on one of the candidate autoantigens in RA; glucose-6-phosphate isomerase (GPI). The arthritogenic role of GPI has been confirmed in two different mouse models: the K/BxN- and GPI-induced arthritis models. Both anti-GPI Abs and citrullinated-GPI peptide Abs have been detected in human RA. Studies conducted in these rodent models have confirmed that the pathogenesis of arthritis involves the localization of autoantigens not only in the joints but also in the circulation. In this review, we revisit and summarize the arthritogenic relevance of GPI in animal RA models and in human RA, and extend the discussion to joint-specific inflammation.

Potential involvement of OX40 in the regulation of autoantibody sialylation in arthritis.

OBJECTIVE: An increased proportion of circulating follicular helper T (Tfh) cells was reported in rheumatoid arthritis (RA), but it remains uncertain how Tfh cells affect antibody hyposialylation. We investigated the regulation of autoantibody hyposialylation by Tfh cells in RA using murine model. METHODS: Behaviours of Tfh cells and their function on B cell promotion were analysed. Change of arthritogenicity and sialylation of autoantibodies during the course of arthritis was examined by mass spectrometry. Tfh-mediated regulation of hyposialylation was investigated, and the responsible cell surface molecule was specified both in vitro and in vivo. The relation between circulating Tfh cells and hyposialylation was analysed in patients with RA. RESULTS: An increase in Tfh, particularly interleukin-17 producing Tfh (Tfh17) cells, at the onset of arthritis and their enhancement of autoantibody production were found. Autoantibodies at the onset phase demonstrated stronger inflammatory properties than those at the resolution phase, and mass spectrometric analysis revealed their difference in sialylation. In vitro coculture showed enhanced hyposialylation by the Tfh cells via OX40, which was highly expressed in the Tfh and Tfh17 cells. Blockade of OX40 prevented the development of arthritis with reduction in Tfh17 cells and recovery of autoantibody sialylation. Analysis of patients with RA showed abundance of OX40-overexpressing Tfh17 cells, and their proportion correlated negatively with the expression of α2,6-sialyltransferase 1, an enzyme responsible for sialylation. CONCLUSIONS: OX40 expressed on Tfh cells can regulate autoantibody sialylation and play a crucial role in the development of autoimmune arthritis.

Effect of Biological Disease-modifying Anti-rheumatic Drugs on Airway and Interstitial Lung Disease in Patients with Rheumatoid Arthritis.

Objective Biological disease-modifying anti-rheumatic drugs (bDMARDs) represent an important advance in alleviating rheumatoid arthritis (RA), but their effect on rheumatic airway disease (AD) and interstitial lung disease (ILD) is still unclear. This study was performed to evaluate the association of the use of different bDMARDs with new-onset or worsening of RA-AD/ILD. Methods We performed a retrospective cohort study of RA patients who received bDMARDs and assessed their AD/ILD before and after drug initiation in our hospital over the past 10 years. We evaluated the serial changes in computed tomography (CT), classified patients according to AD/ILD progression, and analyzed associations between clinical characteristics and outcomes. Results We enrolled 49 patients. Thirty patients received tumor necrosis factor inhibitors (TNFis), 12 received abatacept (ABT), and the remaining 7 received tocilizumab (TCZ). Seventeen patients had ILD, 10 had AD, and 6 had both AD and ILD before the initiation of bDMARDs. New emergence or exacerbation of AD/ILD was observed in 18 patients after drug initiation, while the remaining 31 remained stable or improved. Multiple logistic regression analyses revealed that pre-existing AD was an independent risk factor against the emergence or exacerbation of RA-AD/ILD, and ABT use was a protective factor against it. Conclusion Our study showed that pre-existing RA-AD is associated with future worsening of RA-AD/ILD, and ABT over other bDMARDs was associated with a better prognosis. Future studies to confirm our results are needed.

Peptidyl arginine deiminase inhibition suppresses arthritis via decreased protein citrullination in joints and serum with the downregulation of interleukin-6.

Objective: To explore the relevance of citrullinated proteins and anti-citrullinated protein antibodies (ACPA) via protein arginine deiminase (PAD) inhibition in peptide glucose-6-phosphate isomerase-induced arthritis (pGIA).Methods: Cl-amidine, a PAD inhibitor, was injected into pGIA. Clinical scores and histopathological findings of ankle joints were assessed. Serum ACPA titers were analyzed using ELISA. Citrullinated protein expression in joints and sera were examined with immunohistochemistry and Western blot analysis, respectively. Serum levels of IL-6, TNFα, and IL-1ß were measured with cytometric bead array (CBA). Gene expression levels of IL-6 and TNFα in joints, lymph nodes, and spleens were analyzed with quantitative PCR. GPI-specific productions of IFNγ and IL-17 from T cells in lymph nodes were evaluated.Results: Cl-amidine treatment significantly reduced arthritis severity while ACPA titers tended to be lower, but not significantly different compared to the control. Citrullinated proteins in joints and sera from treated mice were clearly decreased. With Cl-amidine treatment, serum IL-6 levels were significantly decreased, and IL-6 and TNFα gene expression were significantly reduced in joints. IL-17 production from GPI-specific T cells tended to be lower in Cl-amidine-treated mice, but not significantly different.Conclusion: Our results suggested that PAD-mediated citrullinated protein was involved in the pathogenesis of arthritis via IL-6.

Identification of novel biomarker as citrullinated inter-alpha-trypsin inhibitor heavy chain 4, specifically increased in sera with experimental and rheumatoid arthritis.

BACKGROUND: Anticitrullinated protein antibodies (ACPA) and citrullinated proteins play key roles in the pathogenesis of rheumatoid arthritis (RA). Many candidate citrullinated antigens have been identified in joints, but citrullinated proteins in sera are mostly uncertain in patients with RA. We explored the expression of citrullinated proteins in joints and sera of experimental arthritis, and we further investigated their specific expression correlated with the disease activity in patients with RA. METHODS: Citrullinated protein expression in tissues was examined by IHC in peptide glucose-6-phosphate isomerase-induced arthritis (pGIA). Serum citrullinated proteins from pGIA were examined by Western blotting, and the sequence was identified by MS. With the same methods, serum citrullinated proteins were analyzed in patients with RA, primary Sjögren's syndrome, systemic lupus erythematosus, and osteoarthritis as well as in healthy subjects, by Western blotting and MS. In patients with RA, the relationship between the expression of the identified protein (inter-alpha-trypsin inhibitor heavy chain 4 [ITIH4]) and clinical features was evaluated, and the levels of citrullinated ITIH4 were compared before and after biological treatment. The antibody response against citrullinated ITIH4 peptide was measured by enzyme-linked immunosorbent assay. RESULTS: Citrullinated proteins were detected specifically in arthritic joints and sera from pGIA relative to controls. In sera, a common band of citrullinated protein at 120 kDa was revealed, and it fluctuated in parallel with arthritis score of pGIA by Western blotting. Interestingly, in 82% of RA patient sera, similar bands of citrullinated protein were specifically detected. These proteins were identified as citrullinated ITIH4, and especially the R438 site was commonly citrullinated between mice and humans. Citrullinated ITIH4 levels were associated with clinical parameters such as C-reactive protein (CRP), rheumatoid factor, and Disease Activity Score in 28 joints as measured by CRP in patients with RA. Its levels were decreased in correlation with the reduction of disease activity score after effective treatment in patients with RA. Moreover, antibody response to citrullinated epitope in ITIH4 was specifically observed in patients with RA. CONCLUSIONS: Our results suggest that serum citrullinated ITIH4 was specifically increased in patients with RA and could be a novel biomarker for assessing disease activity in patients with RA.

TIARP attenuates autoantibody-mediated arthritis via the suppression of neutrophil migration by reducing CXCL2/CXCR2 and IL-6 expression.

TNFα-induced adipose-related protein (TIARP) is a six-transmembrane protein expressed on macrophages, neutrophils and synoviocytes. We reported recently that mice deficient in TIARP (TIARP-/-) spontaneously develop arthritis and are highly susceptible to collagen-induced arthritis (CIA) with enhanced interleukin (IL)-6 production. However, the effects of TIARP on neutrophils and fibroblast-like synoviocytes (FLS) have not been elucidated. We analyzed the roles of TIARP in K/BxN serum transfer model using TIARP-/- mice. Arthritis in TIARP-/- mice transferred with K/BxN serum was significantly exacerbated compared with WT mice. We characterized the differences in neutrophils between wild-type (WT) and TIARP-/- mice by DNA microarray. Overexpression of CXCR1 and CXCR2 was noted in TIARP-/- neutrophils. Neutrophils of TIARP-/- mice showed strong migration activity, which was markedly facilitated by CXCL2 in vitro and in vivo. Moreover, enhanced production of CXCL2 and IL-6 and cell proliferation was noted in TIARP-/- TNFα-stimulated FLS. Blockade of IL-6R significantly attenuated serum-transferred TIARP-/- arthritis with diminished neutrophil recruitment in joints. Our findings suggested that TIARP independently down-regulated CXCL2 and IL-6 production by FLS, and the expression of chemokine receptors (CXCR1 and CXCR2) in neutrophils, with resultant reduction of neutrophil migration into arthritic joints.

Effectiveness of abatacept for patients with Sjögren's syndrome associated with rheumatoid arthritis. An open label, multicenter, one-year, prospective study: ROSE (Rheumatoid Arthritis with Orencia Trial toward Sjögren's syndrome Endocrinopathy) trial.

OBJECTIVE: To clarify the efficacy and safety of abatacept for secondary Sjögren's syndrome (SS) associated with rheumatoid arthritis (RA). METHODS: The primary endpoint of this open-labeled, prospective, observational multicenter study for secondary SS with RA was the remission rate of Simplified Disease Activity Index (SDAI) at 52 weeks after initiation of abatacept. The secondary endpoints included Saxon's test and Schirmer's test. Adverse events and adherence rate during the study period were also analyzed. RESULTS: Thirty-six patients (all females) were enrolled in this study. The mean SDAI decreased significantly from 20.6 ± 11.2 (±SD) at baseline to 10.0 ± 10.5 at 52 weeks (p < 0.05). Patients with SDAI remission increased from 0 (0 week) to 12 patients (33.3%) at 52 weeks. Saliva volume assessed by Saxon's test increased significantly from 2136 ± 1809 (0 week) to 2397 ± 1878 (24 weeks) mg/2 min (n = 34, p < 0.05). Saliva volume increased significantly from 2945 ± 2090 (0 week) to 3419 ± 2121 (24 weeks) mg/2 min in 11 patients with Greenspan grade 1 or 2 of labial salivary gland biopsy (p < 0.05), but no change was noted in 18 patients with Greenspan grade 3 or 4. Tear volume by Schirmer's test increased significantly from 4.2 ± 4.8 (0 week) to 6.4 ± 7.8 (24 weeks) mm/5 min (n = 30, p < 0.05). The adherence rate to abatacept was 80.6% (29/36) over the 52-week period. Twelve adverse events occurred in 10 of the 36 patients, and 7 of these events were infections. CONCLUSION: Abatacept seems to be effective for both RA and SS related manifestations.

Association of anti-Ro/SSA antibody with response to biologics in patients with rheumatoid arthritis.

OBJECTIVE: To compare the effectiveness of three different biologics in anti-Ro/SSA antibody-positive and antibody-negative patients with rheumatoid arthritis (RA). METHODS: The study subjects were 110 biologics naïve patients with RA who started treatment with biologics and examined for anti-Ro/SSA antibody between December 2003 and March 2014. For patients treated with intravenous infliximab (IFX), tocilizumab (TCZ), or abatacept (ABT), we compared the clinical characteristics and changes in composite disease activity index, such as DAS28, SDAI, and CDAI, for 12 months in anti-Ro/SSA antibody-positive and antibody-negative patients. RESULTS: We examined 59 patients (nine were positive and 50 were negative for anti-Ro/SSA antibody) treated with IFX, 27 patients (5 positive and 22 negative) treated with TCZ, and 24 patients (13 positive and 11 negative) treated with ABT. For patients treated with IFX, parameters of disease activity did not change significantly from baseline in anti-Ro/SSA antibody-positive patients, whereas they improved in antibody-negative patients. On the other hand, treatment with TCZ and ABT significantly decreased disease activity, relative to baseline, in both anti-Ro/SSA antibody-positive and antibody-negative patients. Anti-Ro/SSA antibody-positive patients treated with IFX showed higher frequency of HACA and seroconversion of ANA, and lower serum TGF-ß levels. CONCLUSIONS: Positivity to anti-Ro/SSA in RA seems to confer resistance to IFX via production of HACA and ANA, and low serum TGF-ß levels, but not to TCZ and ABT.

Evaluation of changes in magnetic resonance images following 24 and 52 weeks of treatment of rheumatoid arthritis with infliximab, tocilizumab, or abatacept.

OBJECTIVES: To compare MRI findings in rheumatoid arthritis (RA) patients treated with biologic disease-modifying anti-rheumatic drugs (DMARDs). METHODS: The study subjects were 43 RA patients treated with biologic DMARDs (13 with infliximab, 15 with tocilizumab, and 15 with abatacept). They were evaluated using Simplified Disease Activity Index (SDAI) and low-field extremity MRI at baseline, and at 24 weeks and 52 weeks of treatment. RESULTS: Synovitis scores were significantly lower by 24 weeks in all groups, compared with baseline (P < 0.05). Significant improvement in bone marrow edema (BME) scores were noted from baseline to 24 weeks in infliximab and abatacept groups (P < 0.05), but from 24 weeks to 52 weeks in tocilizumab group (P < 0.01). No significant change was found in erosion score. The synovitis score at baseline correlated significantly with SDAI at 24 weeks (P < 0.05), and the score at 24 weeks correlated significantly with SDAI at 52 weeks (P < 0.05). CONCLUSIONS: The results suggest that the inflammatory improvement by infliximab and abatacept may express earlier than those by tocilizumab, despite similar improvement in SDAI. MRI-detected synovitis could be a useful predictor of SDAI at 24 weeks of treatment. The MRI remains the best tool to detect and assess the effects of biologic DMARDs in RA.

Successful Treatment with Infliximab for Refractory Uveitis in a Hemodialysis Patient with Behçet's Disease and a Review of the Literature for Infliximab Use in Patients on Hemodialysis.

A 36-year-old man with a 16-year history of refractory Behçet's disease (BD)-associated uveitis and chronic renal failure requiring hemodialysis suffered from frequent ocular attacks despite treatment with systemic corticosteroids and cyclosporine A. Following infliximab administration, the patient's BD ocular attack score 24 and visual acuity improved. Although he developed mild acute gastroenteritis, he did not experience any other adverse events. In our review of the literature, we identified seven patients on hemodialysis with inflammatory disease successfully treated with infliximab. Infliximab may be effective and safe in cases of BD and other diseases, including in patients under hemodialysis.

Usefulness of MR imaging of the parotid glands in patients with secondary Sjögren's syndrome associated with rheumatoid arthritis.

OBJECTIVE: To assess the correlation between MR imaging (MRI) of parotid glands with X-ray sialography, histopathology of the labial salivary glands, and salivary secretion, in patients with secondary Sjögren's syndrome (SS) associated with rheumatoid arthritis (RA). METHODS: Non-contrast MRI of the parotid glands was performed in 13 secondary SS patients associated with RA who satisfied the revised Japanese diagnostic criteria for SS (1999), and the ACR/EULAR classification criteria for RA (2010). The MRI findings were classified according to the degree of high-intensity signal on T1-weighted images (T1WI) and short inversion time inversion recovery (STIR) images into five grades (0-4), using the modified Nagasaki University grading method. The results of MRI grading were compared with the Rubin and Holt staging of X-ray sialography (0-4), the Greenspan grading of labial salivary gland histopathology (0-4), and salivary secretion by the gum test (ml/10 min). RESULTS: All 13 patients were females, with a mean age of 50.2 ± 11.3 years. According to the MRI grading, 3 patients were Grade 1, 5 were Grade 2, 5 were Grade 3, and none was Grade 0 or Grade 4. The mean stage by X-ray sialography was 1.7 ± 1.0, the mean grade by histopathology was 2.4 ± 1.2, and the mean volume of salivary secretion was 9.7 ± 3.9 ml. The MRI grading correlated significantly with the Rubin and Holt staging and Greenspan grading (P < 0.01 each, Spearman's rank correlation), and significantly and inversely with the results of the gum test (P < 0.05). CONCLUSION: The results suggest that MRI of the parotid glands is a useful noninvasive tool for evaluating destruction and inflammation in the salivary glands.

Efficacy and safety of abatacept for patients with Sjögren's syndrome associated with rheumatoid arthritis: rheumatoid arthritis with orencia trial toward Sjögren's syndrome Endocrinopathy (ROSE) trial-an open-label, one-year, prospective study-Interim analysis of 32 patients for 24 weeks.

Abstract Objective. To assess the efficacy and safety of abatacept for secondary Sjögren's syndrome (SS) associated with rheumatoid arthritis (RA). Methods. The primary endpoint of this 1-year, open-labeled, prospective, observational multicenter study of RA-associated secondary SS was the rate of SDAI remission at 52 weeks after initiation of abatacept therapy. The secondary endpoints included that of Saxson's test and Schirmer's test. Adverse events during the study period were also analyzed. Results. Thirty-two patients (all females) were enrolled in this study. Interim analysis at 24 weeks included assessment of efficacy (n = 31) and safety (n = 32). The mean SDAI decreased from 19.8 ± 11.0 (± SD) at baseline to 9.9 ± 9.9 at 24 weeks (P < 0.05). Patients with clinical remission, as assessed by SDAI, increased from 0 patient (0 week) to 8 patients (25.8%) at 24 weeks. Saliva volume (assessed by Saxson's test) increased slightly from 2232 ± 1908 (0 week) to 2424 ± 2004 (24 weeks) mg/2 min (n = 29). In 11 patients with Greenspan grading 1/2 of labial salivary glands biopsy, saliva volume increased from 2945 ± 2090 (0 week) to 3419 ± 2121 (24 weeks) mg/2 min (P < 0.05). Schirmer's test for tear volume showed increase from 3.6 ± 4.6 (0 week) to 5.5 ± 7.1 (24 weeks) mm/5 min (n = 25; P < 0.05). Five adverse events occurred in five of 32 patients (15.6%), and three of these events were infections. Conclusion. Abatacept seems to be effective for both RA and RA-related secondary SS.

Clinical features of patients with IgG4-related disease complicated with perivascular lesions.

OBJECTIVE: To define the clinical features of IgG4-related disease (IgG4-RD) complicated with perivascular lesions. METHODS: The clinical features of seven patients with IgG4-RD and perivascular lesions diagnosed at the University of Tsukuba Hospital between October 2008 and October 2013, were analyzed, including clinical background, results of imaging studies, satisfaction of the 2011 comprehensive diagnostic criteria (CDC) for IgG4-RD, laboratory data, distribution of perivascular lesions, involvement of other organs, and response to steroid therapy. RESULTS: We studied six men and one woman with a mean age of 66.9 ± 6.7 years (± SD). Six of seven patients were diagnosed as definite IgG4-RD, while the seventh was considered possible IgG4-RD, based on the CDC for IgG4-RD. Serum IgG4 levels at diagnosis were higher than 135 mg/dl in all seven patients (mean, 933 ± 527). Serum C-reactive protein (CRP) levels were elevated in two only (mean, 1.42 ± 3.56 mg/dl). The perivascular lesions were located in the pulmonary artery (n = 1), thoracic aorta (n = 2), abdominal aorta (n = 6), coronary (n = 1), celiac (n = 1), superior mesenteric (n = 1), renal (n = 2), inferior mesenteric (n = 5), and iliac (n = 3) arteries. In addition to perivascular lesions, six patients showed involvement of other organs. All seven patients were treated with prednisolone (0.6 mg/kg/day), which rapidly improved the perivascular and other organ lesions in six patients (the other one patient have not yet been evaluated due to the short follow-up). CONCLUSION: Perivascular lesions show wide distribution in patients with IgG4-RD. Serum CRP levels are not necessarily elevated in these patients. Steroid therapy is effective in IgG4-RD and results in resolution of lesions.

Pulmonary nocardiosis in patients with connective tissue disease: A report of two cases.

Reported here are 2 patients with connective tissue disease who developed pulmonary nocardiosis. Case 1 involved a 73-year-old man with malignant rheumatoid arthritis treated with prednisolone 25 mg/day. Chest X-rays revealed a pulmonary cavity and bronchoscopy detected Nocardia species. The patient was successfully treated with trimethoprim/sulfamethoxazole. Case 2 involved a 41-year-old woman with systemic lupus erythematosus. The patient received remission induction therapy with 50 mg/day of prednisolone and tacrolimus. Six weeks later, a chest CT scan revealed a pulmonary cavity; bronchoscopy resulted in a diagnosis of pulmonary nocardiosis. The patient had difficulty tolerating trimethoprim/sulfamethoxazole, so she was switched to and successfully treated with imipenem/cilastatin and amikacin.