Peripheral blood CD4+ and CD8+ T cell type 1 and type 2 cytokine production in atopic asthmatic and normal subjects

Authors


Sebastian L. Johnston, Department of Respiratory Medicine, National Heart and Lung Institute, St Mary's Imperial College School of Medicine, Norfolk Place, London W2 1PG, UK. E-mail: s.johnston@ic.ac.uk

Abstract

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.

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