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Objective. B cells play an important role in the pathogenesis of autoimmune diseases. The role of Bruton's tyrosine kinase (Btk) in cytokine-induced human B cell differentiation and class-switch recombination remains incompletely defined. This study analysed the effect of Btk on human activated B cells. Methods. Purified B cells from healthy subjects were stimulated with B cell receptor (BCR) and other stimuli with or without a Btk inhibitor and gene expression was measured. The B cell line BJAB was used to assess Btk-associated signalling cascades. Phosphorylated Btk (p-Btk) in peripheral blood B cells obtained from 10 healthy subjects and 41 patients with RA was measured by flow cytometry and compared with patient backgrounds. Results. IL-21 signalling, in concert with BCR, CD40 and BAFF signals, led to robust expression of differentiation- and class-switch DNA recombination-related genes and IgG production in human B cells, all of which were significantly suppressed by the Btk inhibitor. Although phosphorylation of STAT1 and STAT3 was induced by co-stimulation with IL-21, BCR and CD40, STAT1 phosphorylation in the nucleus, but not in the cytoplasm, was exclusively impaired by Btk blockade. High levels of p-Btk were noted in B cells of RA patients compared with controls and they correlated significantly with titres of RF among RF-positive patients. Conclusion. The findings elucidate a model in which Btk not only plays a fundamental role in the regulation of BCR signalling, but may also mediate crosstalk with cytokine signalling pathways through regulation of IL-21-induced phosphorylation of STAT1 in the nuclei of human B cells. Btk appears to have pathological relevance in RA. [ABSTRACT FROM AUTHOR]

Objective. IL-35 is the most recently identified member of the IL-12 family. It consists of EBV-induced gene 3 (EBI3) and IL-12α chain p35. We investigated whether IL-35 enhances the in vitro immunosup-pressive function of peripheral blood isolated from patients with RA. Methods. Peripheral blood was harvested from 17 active and 10 inactive RA patients and IL-35 concentrations were quantified using an ELISA. An expression vector containing IL-35 with a FLAG tag at the carboxyl-terminus was constructed by covalently linking EBI3 and IL-12α (p35). The function of IL-35 was then evaluated in a suppression assay using T cells isolated from human RA patients with CD2, CD3 and CD28 antibodies. Results. Serum IL-35 levels and the number of Treg were decreased significantly in patients with active RA. There was a significant correlation between serum IL-35 and the 28-joint DAS with ESR (DAS28-ESR) in patients with active RA. IL-35 treatment enhanced the regulatory function, suppressing the levels of inflammatory cytokines such as IL-17 and IFN-γ and the cellular growth of effector T cells stimulated by conjugation with CD2, CD3 and CD28. Conclusion. These data revealed that IL-35 might suppress T cell activation during the peripheral immune responses of RA. Therefore our data suggest that IL-35 might have multiple therapeutic targets. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to clarify the mechanism of leucocytapheresis (LCAP) in patients with RA.Methods. Protein profiles of blood samples from two patients with RA obtained via LCAP column inlet and outlet lines were analysed by two-dimensional fluorescence difference gel electrophoresis and mass spectrometry. The lactoferrin (LTF) levels of peripheral and circulating blood samples from seven patients obtained via the LCAP column blood circuit were then determined by ELISA. Peripheral blood samples from 14 patients with RA were exposed to unwoven polyester fibre filters and the LTF level was determined. In addition, morphological changes in neutrophils after exposure to the filter were examined by optical microscopy, electronic microscopy and LTF immunostaining.Results. LTF levels were increased in both samples from the LCAP column outlet and peripheral blood at the end of LCAP treatment. Furthermore, peripheral blood samples exposed to the filter revealed a decreased number of neutrophils and an increased level of LTF. Morphological analysis of the exposed neutrophils showed vacuolization of the cytoplasm and degranulation of LTF-positive granules. These data suggest that LTF stored in the granules of neutrophils is released from the neutrophils caught in the LCAP column.Conclusion. Because LTF has been reported to have multiple anti-inflammatory properties, increased levels of LTF may contribute to the clinical effect of LCAP in patients with RA. [ABSTRACT FROM PUBLISHER]

Objective. The purpose of this study was to determine serum levels of B-cell-activating factor (BAFF) and its clinical association in patients with sarcoidosis.Methods. Serum levels of BAFF from 37 patients and 21 healthy subjects were examined by ELISA. Serum angiotensin-converting enzyme (ACE), lysozyme and IFN-γ levels in sarcoidosis patients were also measured. Isolated monocytes cultured with IFN-γ, IL-4 or IL-10 and their expression of membrane and soluble BAFF were analysed by flow cytometry or ELISA. Peripheral B cell subsets were analysed by flow cytometry. BAFF expression in the granuloma of the skin was examined by immunohistochemistry. ANAs were determined by indirect IF using HEp-2 cells as a substrate.Results. Serum BAFF levels were significantly elevated in sarcoidosis patients when compared with healthy controls. The frequency of skin and eye involvement was significantly higher in patients with elevated serum BAFF than in patients with normal levels. Serum BAFF levels were correlated with serum levels of ACE, lysozyme and IFN-γ. Immunostaining of anti-BAFF in the skin revealed BAFF expression by epithelioid cells of granuloma. In vitro, IFN-γ induced membrane-bound BAFF expression on monocytes and secretion of soluble BAFF by isolated monocytes. In the peripheral blood, sarcoidosis patients showed increased naïve B cells with a reciprocal decrease in memory B cells and plasmablasts. Seventeen of 26 (65%) sarcoidosis patients exhibited ANA positivity.Conclusion. Serum BAFF levels can be used as a surrogate marker of disease activity in sarcoidosis patients. Increased BAFF may be related to the pathogenesis of sarcoidosis. [ABSTRACT FROM AUTHOR]

Objectives. Cathepsin V (CTSV) is a proteolytic enzyme potentially modulating angiogenic processes, collagen degradation and keratinocyte differentiation. We aimed to investigate the clinical association of serum CTSV levels and the mechanism by which CTSV expression is altered in SSc. Methods. Serum CTSV levels were determined by ELISA in 51 SSc and 18 healthy subjects. CTSV expression was evaluated by immunostaining in SSc and normal skin and by RT-real-time PCR in normal and SSc dermal fibroblasts, normal dermal fibroblasts treated with TGF-β1 or Fli1 siRNA and human dermal microvascular endothelial cells (ECs) treated with Fli1 siRNA. Results. Serum CTSV levels were significantly lower in dcSSc and lcSSc patients than in healthy controls. In early-stage dcSSc, serum CTSV levels were remarkably and uniformly decreased compared with healthy controls. The decrease in serum CTSV levels in mid- and late-stage dcSSc and in lcSSc was linked to the development of proliferative vasculopathy. CTSV expression was decreased in microvascular ECs, pericytes/vascular smooth muscle cells and keratinocytes of dcSSc and lcSSc skin and in dermal fibroblasts of dcSSc skin compared with control skin. Consistently, CTSV expression was decreased in cultured dermal fibroblasts from early-stage dcSSc. Furthermore, mRNA levels of the CTSV gene were significantly decreased in normal fibroblasts treated with TGF-β1 or Fli1 siRNA and in human dermal microvascular ECs treated with Fli1 siRNA. Conclusion. Loss of CTSV expression may contribute to the development of fibrosis, vasculopathy and the altered phenotype of keratinocytes in SSc. [ABSTRACT FROM AUTHOR]

Objective. Inducible costimulator (ICOS), expressed on activated T cells, and its ligand, ICOS ligand (ICOSL), expressed on antigen-presenting cells, have been considered a single receptor–ligand pair. Here we investigated the expression of ICOS and ICOSL in patients with SSc.Methods. ICOS expression on peripheral blood T cells, and ICOSL expression on B cells and macrophages was determined by flow cytometry. Expression of ICOS and ICOSL was assessed by immunohistological staining and real-time PCR of lesional skin.Results. ICOS expression levels were specifically increased on both peripheral blood memory T cells and Tregs from early dcSSc patients compared with those from healthy controls. Mean ICOSL expression on B cells or macrophages was comparable between SSc patients and healthy controls. ICOS-expressing T cells, ICOSL-expressing macrophages and mRNA levels of ICOS and ICOSL were increased in the lesional skin of patients with early dcSSc. In vitro ICOS costimulation enhanced production of IFN-γ, IL-4 and IL-17A from T cells in SSc patients vs normal controls. Soluble ICOS levels were significantly increased in SSc patients and were negatively associated with the presence of ACAs and positively associated with CRP values. Serum levels of soluble ICOS were more closely associated with clinical features compared with levels of soluble IL-2 receptor.Conclusion. Augmented ICOS signalling may contribute to the pathogenesis of SSc during early progressive disease. Soluble ICOS levels may be used as a serum marker for the activity and severity of SSc. [ABSTRACT FROM PUBLISHER]