Lower CH50 as a predictor for intractable or recurrent lupus enteritis: A retrospective observational study.

OBJECTIVES: Lupus enteritis (LE) is a rare but well-known gastrointestinal manifestation of systemic lupus erythematosus (SLE). This study was conducted to identify prognostic factors associated with poor responses in patients with LE. METHODS: We consecutively registered patients diagnosed with LE between January 2009 and October 2019, and retrospectively compared their clinical characteristics based on whether they had good or poor responses to treatment. RESULTS: A total of 13 patients (17 episodes) were included. The median age was 41 years, and 12 patients were female. A comparison of clinical characteristics between groups revealed similar computed tomography (CT) findings. However, serum CH50 levels were significantly lower in the poor response group (median [interquartile ranges (IQR)]; 29.2 [25.3-46.9] U/mL vs 19.3 [7.8-24.0] U/mL, p = .0095). More patients in the poor response group had higher titers of anti-cardiolipin ß2-glycoprotein I antibody (anti-CL ß2GPI Ab) and were started on glucocorticoids (GCs) at moderate doses. In multivariable analysis, serum CH50 level was independently associated with poor response to induction therapy. CONCLUSION: Lower levels of CH50 at the time of initial treatment predicted inadequate treatment response in patients with LE.

Activin A Expressed in Rheumatoid Synovial Cells Downregulates TNFα-Induced CXCL10 Expression and Osteoclastogenesis.

OBJECTIVE: Activin A is known to be highly expressed in rheumatoid synovium. In the present study, we investigated the effect of inflammatory cytokines on activin A production and its role in rheumatoid inflammation using freshly prepared rheumatoid synovial cells (fresh-RSC). METHODS: Fresh-RSC from patients with rheumatoid arthritis were obtained and stimulated with multiple cytokines for activin A production. Gene expression levels of activin A and inflammatory cytokines were determined by quantitative PCR (qPCR) analysis. An enzyme-linked immunosorbent assay (ELISA) was used to measure activin A and CXCL10 in culture supernatants. The osteoclasts generated from human peripheral monocytes by RANKL stimulation were identified by tartrate-resistant acid phosphatase staining and bone resorption assay using Osteo plate. The expression levels of NFATc1 and cathepsin K, critical intracellular proteins for osteoclastogenesis, were determined by Western blotting. RESULTS: Activin A production in fresh-RSC was markedly enhanced by the synergistic effect of TGF-ß1 with inflammatory cytokines, including TNFα, IL-1ß, and IL-6. Activin A inhibited TNFα-induced CXCL10, an important chemoattractant for pathogen-activated T cells and monocytes of osteoclast precursors, but it did not affect the expression of inflammatory cytokines and chemokines. In addition, activin A directly inhibited the expression of NFATc1 and cathepsin K, as well as osteoclast formation in human samples. CONCLUSION: Our data indicated that TGF-ß1 is involved in the expression of activin A at inflamed joints. Activin A mainly exerts an anti-inflammatory action, which prevents joint damage via the regulation of CXCL10 and osteoclastogenesis.

TGFß1 Regulates Human RANKL-Induced Osteoclastogenesis via Suppression of NFATc1 Expression.

Osteoclasts are multinucleated giant cells responsible for bone resorption. Various mediators involved in osteoclast differentiation have been investigated as possible therapeutic targets for osteoporosis and rheumatoid arthritis (RA). Although transforming growth factor beta1 (TGFß1) has been described as one such multifunctional cytokine essential for bone remodeling, its effect on osteoclastogenesis remains controversial. Therefore, we sought to examine the effect of TGFß1 on osteoclast generation induced by receptor activator of nuclear factor (NF)-κB ligand (RANKL) in humans. Peripheral blood monocytes, isolated using magnetic bead sorting, were cultured with macrophage-colony stimulating factor (M-CSF) or RANKL with or without TGFß1. Tartrate-resistant acid phosphatase (TRAP) staining, as well as bone resorption assays, revealed that TGFß1 suppressed RANKL-mediated human osteoclast development. Real-time reverse transcription PCR and Western blotting revealed that TGFß1 reduced the gene and protein expression of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), the master regulator of osteoclast differentiation, respectively. Luciferase assays indicated that TGFß1 inhibited the NF-κB p65-stimulated promoter activity of NFATc1. Immunofluorescence analysis demonstrated that TGFß1 abrogated RANKL-induced nuclear translocation of p65. Thus, TGFß1 regulates human RANKL-induced osteoclastogenesis via downregulation of NFATc1 by blocking nuclear translocation of NF-κB, suggesting that TGFß1 may be a potential therapeutic target for RA.

Serum CXCL10 levels are associated with better responses to abatacept treatment of rheumatoid arthritis.

OBJECTIVES: This study aimed to identify therapeutic predictors of abatacept (ABT) treatment in rheumatoid arthritis (RA) in vitro and in patients. METHODS: T cell cytokine, monokine, and chemokine levels in culture supernatants or serum were determined using flow cytometry bead-based immunoassays. CXCL10 mRNA and protein expressions were also assessed using qPCR and ELISA analyses, respectively. In the patient study, 25 ABT-treated patients were analysed retrospectively. The patients were divided into low disease activity (LDA) or non-low disease activity (non-LDA) groups at 24 weeks of ABT treatment. Seven T cell cytokines and CXCL10 levels were compared in these two groups. RESULTS: Peripheral blood mononuclear cells (PBMC) from healthy donors were stimulated by immobilised anti-CD3 with or without ABT for three days, and the levels of 13 T cell cytokines in culture supernatants were determined. ABT significantly inhibited anti-CD3-induced production of IFN-γ. To examine the effect of these T cell cytokines in rheumatoid synovial cells (RSC), RSCs were stimulated with 10% of culture supernatants from anti-CD3-stimulated PBMCs with or without ABT, and the levels of 23 cytokines were determined. Only CXCL10 was significantly reduced by ABT-treated supernatants. In the patient study, CXCL10 levels at baseline were not different between the LDA and non-LDA groups, whereas CXCL10 levels at 24 weeks were significantly decreased in the LDA group only. CONCLUSIONS: ABT treatment significantly affected IFN-γ and CXCL10 cytokine levels in vitro. In addition, serum CXCL10 levels were associated with better responses in ABT treatment.

IL-1ß Enhances Wnt Signal by Inhibiting DKK1.

Aberrant endochondral bone formation in the physis is a unique bone lesion in neonatal-onset multisystem inflammatory disease (NOMID), also called chronic infantile neurologic cutaneous articular (CINCA), the most severe of the cryopyrin-associated periodic syndrome (CAPS) diseases, which are interleukin-1ß (IL-1ß)-related monogenic autoinflammatory diseases. The wingless (Wnt) pathway plays an important role in osteoblast differentiation. In this study, we explored the potential role of IL-1ß on the expression of WNT genes and the Wnt antagonist Dickkopf-1 (DKK1). The expression of WNT and DKK1 in fibroblast-like synoviocytes (FLS), which are articular resident cells, was quantified by quantitative PCR and enzyme-linked immunosorbent assay. Additionally, we used T cell factor (TCF) reporter assays to evaluate the activity of the canonical Wnt signal pathway in the presence or absence of the supernatant of cultured FLS treated with or without IL-1ß and IL-6. Anti-DKK1 antibodies were used to neutralize DKK1. The expression of both canonical and non-canonical WNT genes as well as DKK1 was observed in FLS. The supernatant of cultured FLS suppressed the luciferase activity of the TCF reporter, and this effect was reduced by its pre-treatment with an anti-DKK1 antibody. Both IL-1ß and IL-6 significantly reduced DKK1 production. Furthermore, the supernatant of FLS cultured with IL-1ß or IL-6 showed a reduced inhibitory effect on Wnt signaling, compared with the supernatant of untreated FLS. These data suggest that IL-1ß, like IL-6, dampens DKK1 production, and thereby promotes Wnt signal activation. Therefore, increased levels of IL-1ß may contribute to the dysregulation of endochondral ossification in NOMID/CINCA.