Comparison of IL-17 production by helper T cells among atopic and nonatopic asthmatics and control subjects.

BACKGROUND

T cells, eosinophils, and neutrophils are strongly involved in the pathogenesis of bronchial asthma. Mechanisms that influence neutrophil accumulation and activation in asthma still remain relatively obscure. There is data indicating that IL-17 is produced by T cells and causes the release of neutrophil-mobilizing cytokines from airway epithelial cells, and that in this way it may regulate airway neutrophilia.

METHODS

Peripheral blood mononuclear cells (PBMC) obtained from atopic asthmatics (AA), nonatopic asthmatics (NA), and normal control subjects (NC) were stimulated by immobilized anti-CD3 antibody (Ab) plus soluble anti-CD28 Ab or Dermatophagoidesfarinae (Df) extract. Df-reactive T cell clones were established from PBMC of AA and cultured in the presence of various stimulants. The resulting supernatants were assayed for IL-2, IL-4, IL-5, IL-13, IL-17, and IFN-gamma by specific ELISAs.

RESULTS

PBMC obtained from AA, NA, and NC all produced IL-17 upon immobilized anti-CD3 Ab plus soluble anti-CD28 Ab stimulation. IL-17 production in response to Df extract was significantly induced only in AA. The amount of IL-17 produced by T cell clones stimulated with immobilized anti-CD3 Ab plus soluble anti-CD28 Ab was negatively, but only weakly, correlated with that of IL-4, but not correlated with IL-2, IL-5, IL-13, and IFN-gamma production.

CONCLUSION

T cells producing IL-17 in response to Df antigen exist in the peripheral blood of the sensitized AA. IL-17 production might be regulated by unique mechanisms different from those governing Th1 versus Th2 differentiation.