High-affinity IgE receptor (FcεRI)-bearing cells in bronchial biopsies from atopic and nonatopic asthma

Asthma is characterized by bronchial mucosal inflammation. Although allergen-induced activation of cells binding allergen-specific immunoglobulin E (IgE) through high-affinity receptors (FcεRI) is believed to play some role in asthma, inappropriate synthesis of total or allergen-specific IgE cannot be demonstrated in some ('intrinsic') patients despite the fact that the nature of the bronchial inflammation is similar to that in atopic ('extrinsic') asthmatics. We have studied the numbers and phenotype of FcεRI-bearing cells in bronchial biopsies from 12 atopic and 10 nonatopic asthmatic patients and compared our findings with 10 atopic and 12 nonatopic control subjects using single and double immunohistochemistry. Significantly increased numbers of FcεRI-bearing cells were identified in bronchial biopsies from atopic and nonatopic asthmatics and atopic control subjects when compared with normal controls (p = 0.001, 0.006, and 0.0006, respectively). In asthmatics and atopics the majority of FcεRI-bearing cells were identified as mast cells and macrophages; a much smaller percentage were eosinophils. We conclude that elevated numbers of high-affinity IgE receptor- bearing cells are a feature of bronchial biopsies of asthmatic subjects, irrespective of their atopic status.