To investigate the role of specific IgE and IgG in the various types of asthmatic reaction, we measured specific IgE and IgG levels to Dermatophagoides farinae (D.farinae) using the D. farinae-radioallergosorbent test (RAST) and Phadebas IgG-RAST in 39 house dust asthmatics (11 early responders, 21 dual responders and 7 isolated late responders) and 12 negative responders on house dust bronchoprovocation. There were significant differences in the D. farinae-specific IgE level and skin reactivity to D. farinae and house dust among the 4 groups (p less than 0.05) and the specific IgE level of dual asthmatic responders was the highest and was significantly higher than that of early responders (p less than 0.05). The specific IgG level showed no differences among the 4 groups. These results suggested that the types of asthmatic reaction in house dust asthmatics were closely related to specific IgE level to D. farinae and the specific IgG level seemed not to be related to an isolated late response.