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  • 1
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Increased production of IL-4 and IL-5 and decreased production of IFN-γ by CD4+ T cells has been implicated in asthma pathogenesis. However, CD8+ T cells also produce type 1 and type 2 cytokines and the relative roles of CD4+ and CD8+ T cell cytokine production in asthma have not been previously studied.Objective To determine the production of the type 1 and type 2 cytokines by CD4+ and CD8+ T cell subsets in asthmatic and normal subjects.Methods Intracellular cytokine staining for IL-4, -5, -10, -13 and IFN-γ was analysed in peripheral blood CD4+ and CD8+ T cells from 24 atopic asthmatic and 20 normal subjects.Results Both subsets of T cells produced all cytokines studied and there were no significant differences between CD4+ and CD8+ T cells in their capacity to produce either type 1 or type 2 cytokines. There were significantly increased frequencies of IFN-γ-positive CD4+ (13.1 ± 2.4%, vs. 7.3 ± 1.4%) and CD8+ (20.0 ± 2.9%, vs. 9.6 ± 2.1%) T cells in asthmatic subjects compared with normal subjects (P 〈 0.05), but not in frequencies of CD4+ or CD8+ T cells staining positively for IL-4, -5, -10 or -13.Conclusion The frequencies of peripheral blood CD8+ T cells producing type 1 and type 2 cytokines are comparable with the frequencies of CD4+ T cells. There was an increased frequency of IFN-γ producing CD4+ and CD8+ T cells in asthmatic compared with normal subjects. Further studies investigating T cells derived from the airways and investigating various stages within the disease process are required to further elucidate the importance of type 2 and type 1 T cell cytokine production in the pathogenesis of human allergic disease.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 31 (2001), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Human rhinoviruses (RVs) are the most common precipitants of asthma exacerbations. RV infection of bronchial epithelium results in local airway inflammation inducing eosinophil recruitment and activation. Induction of eosinophil chemoattractants could represent a central mechanism, as well as a prime target for intervention.Objective To assess the effect of RV infection on mRNA expression and production of eosinophil chemoattractants by bronchial epithelial cells in-vitro.Methods BEAS-2B cells were infected with major and minor RVs and the mRNA expression of IL-8, RANTES, MIP-1α, eotaxin, eotaxin-2, MCP-2, MCP-3 and MCP-4 was assessed by reverse transcription PCR. In cases where mRNA induction was observed, a fluoroimmunoassay was used to confirm protein production. To assess the virus-specificity of the observed reactions, cells were also exposed to inactivated RVs.Results RV infection was able to up-regulate mRNA expression of IL-8, RANTES, MIP-1α, eotaxin and eotaxin-2, did not affect MCP-4, while MCP-2 and MCP-3 were not expressed either at baseline or after virus infection. Protein production was confirmed for IL-8, RANTES and eotaxin, but not for MIP-1α. When RVs were inactivated cytokine up-regulation was almost completely lost.Conclusion Infection of bronchial epithelial cells with RVs results in the production of a wide array of mediators that are able to chemoattract eosinophils. These include the eosinophil-specific molecules eotaxin and eotaxin-2, in addition to IL-8 and RANTES, which are the most abundant. Eosinophil recruitment after RV infection of bronchial epithelium could represent a central event in the pathogenesis of virus-induced asthma exacerbations.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Rhinovirus (RV) infection is the commonest trigger of acute asthma exacerbations; however, the immune response to these viruses and any potential implications in the mechanisms leading to asthma exacerbations are not well understood.Objective To assess the effects of in vitro RV infection on the phenotype and expression of costimulatory molecules on peripheral blood mononuclear cells (PBMC) from normal and atopic asthmatic subjects, as a model for RV antigen presentation.Methods PBMC from seven normal and seven asthmatic subjects were exposed to one infectious unit/cell of RV16 for 48 h. Surface expression of CD25, CD28, CD40, CD54, CD80, CD86 and CTLA-4 was evaluated on CD3, CD4, CD8, CD14 and CD19 PBMC subpopulations by three-colour flow cytometry.Results No changes in the percentage of CD3, CD4, CD8 or CD19 were observed. CD14 was significantly reduced by the infection and this was more pronounced in normal subjects. On Th cells CTLA-4 was increased after RV infection only in the asthmatic group. Levels of CD80 and CD86 in the control cultures were lower in the asthmatic group. RV infection induced a significant increase of CD80 on monocytes and of CD86 on B cells, which occurred in both groups but were less marked in atopic asthmatic subjects.Conclusion Exposure of PBMC to RV is able to activate the antigen presentation machinery. Differences between normal and atopic asthmatic individuals are compatible with the hypothesis that an aberrant immune response to RV may be involved in the development of acute exacerbations in atopic asthmatic subjects.
    Type of Medium: Electronic Resource
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