Expression of interleukin-1 beta (IL-1beta) and interleukin-1 receptor antagonist (IL-1ra) on asthmatic bronchial epithelium

Accumulating evidence suggests that the cytokine network is central to the immunopathology of bronchial asthma and recent findings have suggested that naturally occurring cytokine antagonists may also be involved. In this study we looked at the expression of interleukin-1 beta (IL-1beta) and its naturally occurring receptor antagonist, IL-1ra, in the normal and asthmatic bronchial wall. Frozen bronchial biopsies from 12 normal and 18 asthmatic individuals were double stained with EBM11 (a CD68 macrophage marker) and either a rabbit anti-IL-1beta or a rabbit anti-IL-1ra. Hue-saturation-intensity color image analysis (HSI) was used to quantify the brown immunoperoxidase reaction product present on the bronchial epithelium. There was an increased expression of both IL-1beta and IL-1ra in the asthmatic bronchial epithelium, p < 0.0002 and p < 0.0001, respectively. Additionally, the numbers of macrophages, of IL-1beta producing cells, and the percentage of macrophages producing IL-1beta were significantly increased in the asthmatic submucosa (p < 0.004, p < 0.002, and p < 0.008, respectively).