Objective: To study the effects of specific immunotherapy with standardized house dust mite extract on the lung function and immunologic markers in children with asthma.
Methods: Thirty-two children with mild to moderate asthma who were allergic to house dust mite were assigned to two groups: an immunotherapy group that received subcutaneous specific immunotherapy with standardized house dust mite extract beside glucocorticoids treatment (n=15) and a control group that received glucocorticoids treatment alone (n=17). Lung function was determined before treatment and 3, 6, 12, 18 and 24 months after treatment. The frequency of asthma attacks was observed before treatment and 12 and 24 months after treatment. Serum immunological markers, including total IgE, specific IgE and specific IgG4 against house dust mite (Dermatophagoides pteronyssinus, Der P), ECP, IL-10, IL-4, and IFN-γ, were measured before treatment and 12 and 24 months after treatment.
Results: The parameters of lung function were kept at the normal level or near normal level after treatment in the immunotherapy group. Compared with before treatment, the percentage of patients without asthma attacks increased significantly after treatment in the immunotherapy group (P<0.05) and increased more significantly with a prolonged treatment time (P<0.05). The level of serum sIgG4 against Der P increased significantly throughout the period of the immunotherapy treatment compared with before treatment (P<0.01). There were no significant differences in the levels of serum total IgE, sIgE against Der P, ECP, IL-10, IL-4 and IFN-γ before and after treatment in the immunotherapy group. There were no significant differences in all the parameters measured before and after treatment in the control group.
Conclusions: Subcutaneous specific immunotherapy with standardized house dust mite extract for two years decreases the frequency of asthma attacks and the lung functions are kept in a normal level in children with asthma. The role of the specific immunotherapy may attribute to the increased level of serum sIgG4 against Der P.