Abstract
Background - Asthma is characterised pathologically by an inflammatory pulmonary infiltrate rich in T helper (Th) 2 cells and eosinophils. Interleukin (IL)-12 is a heterodimeric cytokine critical for driving the development of uncommitted Th cells to express a Th 1 phenotype. Reduced pulmonary production of IL-12 may therefore play a role in the pathogenesis of asthma by contributing to the pulmonary cytokine imbalance seen in asthma. Methods - IL-12 p70 protein levels in bronchoalveolar lavage fluid and p70 protein levels and IL-12 messenger RNA in alveolar macrophage cultures from normal and atopic asthmatic subjects were measured. Results - There was a significant difference between the mean IL-12 p70 protein level in the bronchoalveolar lavage fluid from asthmatic subjects (37.5 pg/ml) and from normal subjects (131 pg/ml, p = 0.04). Alveolar macrophages from asthmatic subjects produced significantly less IL-12 protein (30 pg/ml) and messenger RNA than those from normal subjects (69.5 pg/ml, p<0.005). These differences were not caused by inhibition of IL-12 production by IL-10 nor to generalised hyporesponsiveness of asthmatic alveolar macrophages from subjects to the effects of interferon (IFN)-γ. Conclusions - Pulmonary IL-12 production is lower in asthmatic subjects. This reduction is not the result of generalised hyporesponsiveness to IFN-γ. Reduced IL-12 levels may contribute to the development of asthmatic pulmonary inflammation through dysregulation of Th cell development.
Original language | English (US) |
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Pages (from-to) | 842-847 |
Number of pages | 6 |
Journal | Thorax |
Volume | 55 |
Issue number | 10 |
DOIs | |
State | Published - 2000 |
Externally published | Yes |
Keywords
- Alveolar macrophages
- Asthma
- Interferon γ
- Interleukin 12
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine