Immunoblot analysis of specific IgE, IgG, IgG1 and IgG4 response to Dermatophagoides farinae according to allergen inhalation bronchial challenge test

초록

D. farinae (Df) is the most important inhalant allergen in Korea. Df elicited not only specific-IgE (sIgE) but also sIgG, sIgG1 and sIgG4 responses. The exact role of sIgG, sIgG1 and sIgG4 has not been clearly clarified. And, it is not known what antigenic components are associated with the asthmatic reaction following Df allergen exposure. To investigate this problem, we performed Df-inhalation bronchial challenge in 49 asthmatics with positive Df skin test and serum sIgE, and evaluated sIgE, sIgG, sIgG1 and sIgG4 responses to Df by immunoblotting according to the results of challenge test. 26 patients showed positive asthmatic reaction after inhalation of Df crude extracts, but 23 had no significant change. For statistical convenience, we chose 10 definite sIgE binding bands with MW of 100, 80, 65, 34, 30, 28, 19, 15, 13 and 12.5 kDa and compared Ab-binding rate to each components. Positive sIgE binding reactions to 34, 15 and 13 kDa were significantly higher in challenge positive group than in negative group. Positive sIgG reactions to 15, 13 and 12.5 kDa and sIgG1 binding to 15 kDa were significantly higher in challenge positive group. However, positive sIgG4 responses to 30, 19 and 13 kDa were significantly higher in challenge negative group. These results suggest that low MW proteins of Df are important antigens associated with sIgE-mediated asthmatic reaction, but sIgG4 response to certain allergenic components might have a preventive role in asthmatic reaction.