Specific immunoglobulin E and immunoglobulin G4 toward major allergens of house-dust mite during allergen-specific immunotherapy.

Background: Specific immunoglobulin E (sIgE) and sIgG4 to house-dust mite (HDM) major allergens during allergen immunotherapy (AIT) and their clinical relevance remain unclear. Objective: To investigate the variation of sIgE and sIgG4 to HDM major allergens and the correlation with clinical responses during AIT in patients with allergic rhinitis. Methods: Thirty-nine patients with HDM allergy were divided into the AIT group (taking immunotherapy) and the control group (medication only use). The AIT group was subdivided into negative clinical responses to AIT (nAIT) group and positive clinical responses to AIT (pAIT) group according to symptom relief and subjective evaluation. sIgE and sIgG4 to Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df), and their group 1 and group 2 major allergens (Dp1, Df1, Dp2, and Df2) were measured before AIT, at 6 months, and at 1 year after starting AIT. Results: Dp2, Df, and Df2 sIgE values decreased significantly in the pAIT group versus the nAIT group after 1 year of AIT (median values of delta change were Dp2, -10.09 versus 5.89 kU/L, p = 0.001; median values of Df were -9.69 versus 17.54 kU/L, p = 0.004; median values of Df2 were -11.06 versus 20.08 kU/L, p = 0.013). There was a robust increase in the sIgG4 values to Dp, Df, and their major allergens in both the pAIT and the nAIT groups overall after 1 year of treatment. Conclusion: Patients with a positive response to AIT showed a significant reduction of HDM group 2 sIgEs compared with those with a negative response to AIT, which indicated that a decrease in group 2 sIgEs could be a marker that reflected AIT clinical efficacy.