Cockroach cause of allergic asthma. Its specificity and immunologic profile

To assess the etiologic role of cockroach antigen in bronchial asthma, 46 asthmatic subjects were studied using in vitro assays for total and cockroach-specific IgE antibodies (IgEcr) and the responsiveness of the skin and bronchial tree to the antigen challenge in vivo. Asthmatic subjects were divided into skin test-positive (PCR) and skin test-negative (NCR) groups according to immediate skin response to cockroach antigen. The 28 in the PCR group showed high total IgE (1,901 ng/ml) and a high cockroach-specific IgE antibody level (329%) in the serum compared to the 10 in the NCR group (IgE: 915 ng/ml, IgEcr:84%) (p less than 0.001). Bronchial challenge with the antigen revealed immediate asthmatic reaction (30/33) and late asthmatic reaction (16/33) in the PCR asthmatics, whereas the NCR asthmatics showed neither immediate asthmatic reaction (2/13 showed questionable decrease in FEV1) nor late asthmatic reaction (p less than 0.001). A marked increase in peripheral eosinophils (758% vs 121%) was noted following antigen inhalation in the skin test-positive asthmatics (p less than 0.025). The results indicate that cockroach antigen causes antigen-specific IgE-mediated bronchial asthma and peripheral eosinophilia in specifically sensitized asthmatic subjects.