IgE responses to Dermatophagoides pteronyssinus native major allergens Der p 1 and Der p 2 during long-term specific...

We investigated by ELISA the IgE response to whole extract of the house-dust mite Dermatophagoides pteronyssinus (Dp) and to the native major allergens, Der p 1 and Der p 2, in sera from 18 adult patients (group A) with Dp-allergic asthma before (t0) and 1, 2, 3, and 4 (t1-t4) years after subcutaneous specific immunotherapy (SIT). A qualitative reduction (P = 0.05) of the IgE responses to Dp and Der p 2 was observed from t1 to t4, but a highly statistical significant decrease appeared at t3 (P < 0.01). With regard to Der p 1 IgE values, the immunotherapy induced a significant decrease (P < 0.01) at t3, but not before. In group A, the IgE responses to Der p 1 and Der p 2 were not correlated at t0 (rs = 0.31; P = 0.21) but were correlated at t3 (rs = 0.78; P = 0.001). We also examined sera from 14 adult patients (group B, same SIT schedule as group A) who were without respiratory symptoms at the end of the third year (t3) of Dp SIT. At this time (t3), there were no significant differences in Der p 1 and Der p 2 IgE levels between group A and group B.