ABSTRACT
The unavoidable perennial allergens as House dust mites [HDM] is the commonest cause of chronic allergic respiratory airway syndrome [CARAS] frequently seen nowadays either in the form of allergic rhinitis [AR] and/or bronchial asthma [BA] recently this is best treated with immunotherapy. Although there are many investigations for the diagnosis of these allergic conditions most of the used tests are unsafe, non-specific or invasive. Thus the aim of this study was to detect the validity of local HDM allergen-specific IgE assay in blown nasal secretion for diagnosis of CARAS as a specific safe easy test and to show its value for future immunotherapy in comparison to other allergic investigations. So, this study involved 45 patients with CARAS and had positive skin prick test for HDM allergens and elevated serum total IgE level. They were 26 males and 19 females with a mean age 31.8 years. The patients were classified into 3 groups: group-I including 15 patients with AR, group-II with 15 patients having allergic nasal polypi and group-III involving 15 patients presented with BA only. While, 15 normal volunteers were included as controls with age and sex matched. All individuals were subjected to pulmonary function test [FEV1], nasal scraping cytology [for local eosinophilic count], HDM-speciflc IgE assay in serum, induced sputum and blown nasal secretion by ELISA technique and transmission electron microscopic [TEM] examination of 4 nasal biopsies [one from each group and one control]. The TEM examination showed intense allergic changes in the nasal mucosa of the patients in comparison to the control in the form of infiltration with active allergic cells. Also, local eosinophilic count was highly significantly increased in all patients, while the FEV1 was significantly reduced only when there is marked airway obstruction as in BA and nasal polypi patients. On the other hand, local HDM-specific IgE in airway secretions [induced sputum and blown nasal secretion] were significantly increased in the patients of the three groups but highly significantly increased in nasal secretion of patients with nasal polypi. In contrast serum HDM-specific IgE was non-significantly increased in patients with allergic rhinitis with or without nasal polypi and only significantly raised in BA patients. From these results we concluded that HDM-specific IgE assay in blown nasal secretion is a specific easy safe non-invasive invitro test for the diagnosis of CARAS suitable for immunotherapy with identification of the specific allergen to be used