The change of allergen-specific IgG subclass antibodies during immunotherapy in mite-sensitive asthmatic children

Fifty-six Dermatophagoid farinae (D.f)-sensitive asthmatic children were hyposensitized by D.f-crude extract for two years. Serum total IgG subclass antibodies and D.f-specific IgE and IgG subclass antibodies were measured by ELISA before and after 2 years of treatment. The results showed that 1) After two years of treatment, there were significantly higher levels of total serum IgG1 in both responder and non-responder groups than those before treatment (p < 0.01). The responder group also had significantly higher values of total IgG2 and IgG4 after immunotherapy (IT) (p < 0.05), but not in the non-responder group. 2) The serum levels of D.f-specific IgG3 and IgG4 antibodies in responder group increased significantly after IT (p < 0.05). On the contrary, the D.f-specific IgE and IgG1 in the responder group were significantly lower than those before IT. No signibody titres before and after IT was found in non-responder group. 3) There was a significant correlation between the total IgG4 and D.f-specific IgG4 antibody (r = 0.634, p < 0.01). The correlation coefficient was 0.634. No correlation was found between the other IgG subclass antibodies and D.f-specific IgG subclass antibodies. 4) Correlations between the levels of D.f-specific IgE and IgG subclass antibodies were highly significant both in IT-responder and non-responder groups. There was a significant correlation between the levels of D.f-specific IgG1 and IgG4 in non-responders, while no relationship was observed in the responder group. In conclusion, an increase of allergen-specific IgG4 and decrease of allergen-specific IgG1 antibodies following immunotherapy can be of clinical benefit to allergic individuals, at least to most children suffering from mite-sensitive asthma.