Cardamonin inhibits pro-inflammatory cytokine production and suppresses NO pathway in PBMCs from patients with primary Sjögren’s syndrome

Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disorder with a complex pathophysiology primarily affecting exocrine glands, leading to compromised secretory function. Recent studies imply that many inflammatory mediators, such as pro-inflammatory cytokines and nitric oxide, are critical in the development and perpetuation of pSS systemic manifestations. In the current study, we aimed to investigate the ex vivo immunomodulatory effect of cardamonin (C₁₆H₁₄O₄), on pro-inflammatory cytokines, TNF-α, IL-6 and inducible nitric oxide synthase (iNOS) expression during pSS. For this purpose, peripheral blood mononuclear cells isolated from pSS patients and healthy controls were cultured with different concentrations of cardamonin. Cytokine levels were measured by ELISA and NO production was assessed using the Griess method. Inducible nitric oxide synthase expression and NF-κB activity were analyzed by immunofluorescence staining. Our results suggest that cardamonin inhibits TNF-α, IL-6 and NO production and downregulates iNOS expression and NF-κB activation. Collectively, our results highlight the ex vivo immunomodulatory effects of cardamonin on pro-inflammatory cytokine production and NO pathway in pSS patients. Therefore, cardamonin is a potential candidate for controlling inflammation during pSS.     

Interleukin-6 is responsible for aberrant B-cell receptor-mediated regulation of RAG expression in systemic lupus erythematosus

Defective regulation of secondary immunoglobulin V(D)J gene rearrangement promotes the production of autoantibodies in systemic lupus erythematosus (SLE). It remains unclear, however, whether the regulation of the recombination-activating genes RAG1 and RAG2 is effective in SLE. RAG1 and RAG2 messenger RNA expression was analysed before and after in vitro activation of sorted CD19(+) CD5(-) B cells with anti-immunoglobulin M antibodies, in 20 SLE patients and 17 healthy controls. The expression of CDK2 and p27(Kip1) regulators of the RAG2 protein, were examined. The levels of interleukin-6 (IL-6) and its influence on RAG regulation were also evaluated in vitro. SLE patients had increased frequency of RAG-positive B cells. B-cell receptor (BCR) engagement induced a shift in the frequency of kappa- and lambda-positive cells, associated with a persistence of RAG messenger RNA and the maintenance of RAG2 protein within the nucleus. While expression of the RAG2-negative regulator CDK2 was normal, the positive regulator p27(Kip1) was up-regulated and enhanced by BCR engagement. This effect was the result of the aberrant production of IL-6 by SLE B cells. Furthermore, IL-6 receptor blockade led to a reduction in p27(Kip1) expression, and allowed the translocation of RAG2 from the nucleus to the cytoplasm. Our study indicates that aberrant production of IL-6 contributes to the inability of SLE B cells to terminate RAG protein production. Therefore, we hypothesize that because of constitutive IL-6 signalling in association with BCR engagement, SLE B cells would become prone to secondary immunoglobulin gene rearrangements and autoantibody production.     

RAG-mediated secondary rearrangements of B-cell antigen receptors in rheumatoid synovial tissue

Rheumatoid arthritis (RA) induces major changes in synovial tissue (ST) and cartilage and bone destruction. Still, its pathogenesis is poorly understood. Accumulating evidence points to an important role for B lymphocytes. Rheumatoid-ST is characterized by activation of the synoviocytes and infiltrated by various inflammatory cells such as B and T lymphocytes. The infiltrate is diffuse or organized as germinal centers (GCs). These accommodate the immune response and favor self-tolerance breakdown. Receptor revision in B cells results from re-expression of the recombination activating genes (RAGs) which reinitiate immunoglobulin gene recombination, and modify the B-cell antigen receptor accordingly. In rheumatoid ST, secondary VDJ rearrangements occur and RAG proteins are detected. The mechanism that triggers and controls this revision remains elusive. We favor the hypothesis that such an uncontrolled process leads to autoimmunity.     

A Conspicuous Role For B Cells In Sjögren’s Syndrome

Although the relative contributions of T cells and B cells in Sjögren’s syndrome (SS) are far from being settled, recent studies have suggested a crucial role for B cells in its pathophysiology. Early investigations have focused on the ability of B cells to produce autoantibodies, and new studies have enlarged the range of their functions. For example, beyond the paradigm that T lymphocytes maintain strict control over B cells, the latter cells are now acknowledged to solicit their own help from the former cells and release a flurry of cytokines. Further, some of these B cells act as antigen-presenting cells. Increased levels of the B cell activating factor (BAFF) found in SS may be responsible for high numbers of circulating Bm2/Bm2′ cells and associated functional abnormalities of B cells, such as a BAFF-induced increased expression of CD19, which decreases the required strength generated by antigen binding for transmitting its signal. This review reports compelling evidence that B cells are involved in the pathophysiology of SS. As this brings novel prospects for the treatment of the disease, it is no surprise that B cell ablative treatment has proven to be relatively efficacious in SS.     

BAFF,a New Target for Intravenous Immunoglobulin in Autoimmunity and Cancer

Intravenous immunoglobulin (IVIg) has been used to treat autoimmune diseases and lymphoid malignancies with some therapeutic effect. In both these pathological conditions, there is an overproduction of BAFF (for “B-cell-activating factor of the TNF family”), and APRIL (for “a proliferation-inducing ligand”). The presence of antibodies (Abs) with BAFF and APRIL specificities in IVIg preparations was investigated by enzyme-linked immunosorbent assay, and Western Blot analysis. Apoptosis was measured by the annexin-V binding method, and confirmed using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. Nonglycosylated recombinant BAFF, glycosylated affinity-purified BAFF, and recombinant APRIL (but not TNFα), were recognized by certain IgG in IVIg, and their F(ab′)₂ fragments. Steric hindrance prevented the antiapoptotic effects of BAFF on B-lymphocytes. This work documents the presence of anti-BAFF and anti-APRIL Abs in IVIg. These can functionally neutralize the role of BAFF in B-cell survival. These anti-BAFF IgG might amend deleterious effects of BAFF in B-cell-mediated autoimmune diseases.     

周围神经组织工程生物材料的生物相容性评价

目的:总结周围神经组织工程生物支架材料生物相容性评价方法的进展。资料来源:应用计算机检索CNKI1990-01/2006-12有关周围神经组织工程生物材料生物相容性评价方面的文章,检索词“神经,组织工程,生物材料,生物相容性”,限定文献语言种类为中文。同时计算机检索ElsevierScienceE-journals1990-01/2006-12有关周围神经组织工程生物材料生物相容性评价方面的文章,检索词“nerve,tissueengineering,biomaterial,biocompatibility”,限定文献语言种类为English。资料选择:对资料进行初审,选取周围神经组织工程生物材料方面的相关文献,开始查找全文。排除中枢神经系统文献。对剩余的文献进行分析,总结研究内容。资料提炼:共收集到相关文献168篇,72篇符合纳入标准,其中30篇有关周围神经组织工程生物材料生物相容性评价方面的文献用于综述。资料综合:周围神经组织工程生物材料生物相容性评价可分为体外和体内两个方面。体外评价即利用生物材料与细胞共培养,通过观察细胞的形态,测定细胞的活力和凋亡等反映细胞的细胞毒性。体内评价最常用大鼠坐骨神经模型,通过普通和免疫组化染色、血液指标检测、器官病理切片等反映生物材料体内局部和整体的相容性。目前,生物相容性评价以短期为主,而其长期评价也是必须的。结论:在常用方法的基础上,一些新的方法逐渐被运用到周围神经组织工程支架材料的生物相容性评价上。对于各种评价方法的“性价比”还需要进一步的分析,以建立一套基本评价体系。     

Improvement of Sjögren's syndrome after two infusions of rituximab (anti-CD20)

OBJECTIVE: There is evidence to support a dominant role for B cells in the pathophysiology of primary Sj?gren's syndrome (SS). Therefore, we evaluated the safety and efficacy of anti-CD20 monoclonal antibody. METHODS: Sixteen patients who met the new American-European Consensus Group criteria for primary SS and scored >50 on at least 2 of 4 visual analog scales (VAS; 100 mm) evaluating global disease, pain, fatigue, and global dryness received infusions of low-dose rituximab (375 mg/m(2)) at weeks 0 and 1 without steroid premedication. RESULTS: Slow rituximab infusions (100 mg/hour) were well tolerated, with only 1 patient experiencing serum sickness-like disease. There was a dramatic reduction in B cells of the blood and salivary gland (SG). At week 12, VAS scores with respect to fatigue and dryness (P < 0.05), tender point count (P < 0.035), and quality of life as evaluated by the Short Form 36 questionnaire (SF-36; P < 0.001) were significantly improved. At week 36, significant improvements were noted in the 4 VAS scores (P < 0.05), tender joint count (P = 0.017), tender point count (P = 0.027), and SF-36 (P < 0.03). Pulmonary manifestations were ameliorated in 1 patient. Patients with improvements on at least 3 of the 4 VAS scores at any visit (n = 11) had a shorter disease duration than the other patients (n = 5; mean +/- SD duration 3.8 +/- 5.4 versus 30.1 +/- 29.5 years; P = 0.02). CONCLUSION: Low-dose rituximab infusions were well tolerated without the benefit of steroids. Infusions induced a rapid depletion of B cells in the blood and SG and could improve primary SS. Controlled studies are needed.