Fibroblasts have been implicated in psoriatic inflammatory processes. The aim of the study was to evaluate soluble interleukin 2 receptor (sIL-2R), interleukin 6 (IL-6), and interleukin 8 (IL-8) plasma levels in psoriatic patients and IL-6 and IL-8 levels in fibroblast culture supernatants. Cytokines levels in plasma and supernatants were measured by ELISA. Plasma sIL-2R, IL-6, and IL-8 levels were higher before the treatment in comparison to healthy controls (P < 0.001) and decreased after treatment. Fibroblasts from healthy controls, psoriatic lesional skin, and noninvolved psoriatic skin, when stimulated with tumor necrosis factor alpha, released considerable amounts of IL-6 and IL-8. No significant difference between healthy controls and psoriatic fibroblasts was observed. Monitoring plasma sIL-2R levels could be employed as a reliable method of psoriasis activity. IL-8 and IL-6 plasma levels seem to reflect psoriasis activity, and treatment response, respectively. Fibroblasts are not a major source of increased IL-6 and IL-8 production in psoriasis.

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Thymosin ␤4 (T␤4), a 4.9-kDa polypeptide primarily known as a main G-actin-sequestering peptide, is present in high concentrations in various cells and in the circulation. We have found that T␤4 upregulates the expression of plasminogen activator inhibitor 1 (PAI-1) in endothelial cells measured both at the level of mRNA and protein synthesis. This effect seems to be cell specific and was not observed when other cells such as human fibroblasts, PC3, and U937 were tested. T␤4

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The prior treatment of guinea pigs with nicotinamide diminished the symptoms of experimental bronchial asthma and the intensity of anaphylactic shock. Nicotinamide was also found to inhibit anaphylactic mast cell degranulation in mice and histamine release from rat-isolated peritoneal mast cells by compound 48/80. The role of nicotinamide in bronchial asthma is discussed.

Upon contact with allergen, sensitized mast cells release highly active proinflammatory mediators. Allergen-mediated mast cell activation is an important mechanism in the pathogenesis of atopic asthma. Asthmatic patients are especially susceptible to air pollution. Epidemiologic studies found a positive correlation between severity of symptoms among asthmatic patients and the level of particulate matter (PM) in the air. Among the constituents of PM are metals and transition metals, which could mediate some of its adverse effects on human health. We sought to determine the effect of metal and transition metal ions on allergen-mediated mast cell activation. We observed that several metal and transition metal ions activated mast cells and enhanced allergen-mediated mast cell activation. Thus, Al(3+), Cd(2+), and Sr(2+) induced release of granule-associated N-acetyl-ss-d-hexosaminidase, and Al(3+) and Ni(2+) enhanced antigen-mediated release. Metal and transition metal ions also induced significant secretion of interleukin (IL)-4 and increased antigen-mediated IL-4 secretion in mast cells. These effects of metal and transition metal ions on mast cells were observed at concentrations that do not result in direct cytotoxicity and might be relevant for environmental exposure. Thus, metals and transition metals could increase the level of allergen-mediated mast cell activation, which might be one of the mechanisms mediating exacerbation of allergen-driven asthma symptoms by air pollution.

Background: Integrin receptors are engaged in the upregulation of mast cell adhesion to extracellular matrix components upon stimulation with cytokines and antigen. Fibronectin receptor containing the α5-integrin subunit is critical for mast cell interaction with the extracellular matrix protein fibronectin (FN). Methods: The murine MCP5/L mast cell line was employed to investigate the process of FcΕRI-mediated mast cell adhesion to FN. RT-PCR and cytofluorimetric analysis were used to assess the expression of α5 integrin in MCP5/L mast cells. Radiolabelled mast cells were sensitized with monoclonal IgE and used in adhesion assays. Anti-α5-integrin antibody (Ab), monovalent hapten and metabolic inhibitors were used to characterize antigen-mediated mast cell adhesion to FN. Results: Addition of antigen to IgE-sensitized cells resulted in transient upregulation of mast cell adhesion to FN with a maximum adhesion following 30 min of incubation. Mast cell adhesion was inhibited with anti-α5-integrin monoclonal antibodies blocking FN receptor or with excess monovalent hapten preventing antigen-mediated IgE cross-linking. The presence of the protein kinase C (PKC) inhibitor staurosporine also inhibited mast cell adhesion in a dose-dependent fashion. The process of FcΕRI-mediated upregulation of mast cell adhesion to FN was not associated with an increase in surface expression of mast cell FN receptors. Conclusion: The major FN receptor on MCP5/L mast cell surface, an integrin containing the α5 subunit mediates a transient change in mast cell adhesiveness following IgE cross-linking. FcΕRI-derived signals engage PKC and upregulate mast cell adhesion in a process which might involve changes in integrin avidity rather than integrin expression.