BACKGROUND: House dust mite (HDM) elicit not only specific-IgE (sIgE) but also IgG (sIgG) responses, but the exact role of sIgG has not been clearly clarified. There has been no published report on antigenic components of HDM directly associated with the asthmatic reaction following HDM exposure in patients with HDM-sensitive bronchial asthma. OBJECTIVE: This study was performed to evaluate the role of antibody response to HDM and to confirm the asthma related-antigenic components of HDM in patients with HDM-sensitive asthma. METHOD: A total of 49 patients with HDM-sensitive asthma were enrolled. We preformed D. farinae-bronchial challenge test, and analyzed sIgE, sIgG, sIgG1 and sIgG4 response to D. farinae by immunoblotting according to the results of challenge test. RESULT: Twenty-six patients (53.1%) showed positive asthmatic reaction after exposure to D. farinae extracts, but 23 (46.9%) showed no significant response. For statistical convenience, we chose 8 specific IgE binding bands with molecular weight of 65, 34, 30, 28, 19, 15, 13 and 12.5 kDa and compared antibody 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 and 13 kDa were significantly higher in challenge positive group. However, positive sIgG4 responses to 30 and 19 kDa were significantly higher in challenge negative group. CONCULSION: These results suggest that low molecular weight proteins of D. farinae such as 34, 15 and 13 kDa are important antigens associated with IgE-mediated asthmatic reaction, but sIgG4 response to certain allergenic components (30 and 19 kDa) might have a role in prevention of asthmatic reaction after allergen exposure.