OBJECTIVETo study the clinical effect and mechanisms of specific sublingual immunotherapy (SLIT) for the treatment of allergic rhinitis or asthma in children.

METHODSThirty children suffering from Dermatophagoides farinae-allergic rhinitis or asthma (case group) and 30 healthy children (control group) were enrolled in this study. The case group accepted SLIT between January and December 2011. The ratio of forced expiratory volume in one second (FEV1) and its expected value, the ratio of airway resistance and its expected value, peripheral blood eosinophil (Eos) count and serum levels of IL-17 and IL-35 were measured before treatment and one and two years after treatment. The rhinitis or asthma symptom scores were rated and the level of asthma control was monitored.

RESULTSSerum IL-17 level in the case group was significantly higher than in the control group before treatment and one year after treatment (P<0.01). Furthermore, serum IL-17 level in the case group gradually decreased from before treatment to 1 year to 2 years after treatment (P<0.01). By two years of treatment, there was no significant difference in serum IL-17 level between the case and control groups (P>0.05). The changes of serum IL-35 level after treatment were opposite to serum IL-17 in the case group. The ratio of FEV1 and its expected value gradually increased from before treatment to 1 year to 2 years after treatment (P<0.01) in the case group. In contrast, the change of the ratio of airway resistance and its expected value and Eos count gradually decreased from before treatment to 1 year to 2 years after treatment (P<0.01) in the case group. More patients achieved improved rhinitis or asthma symptom scores two years after treatment than one year after treatment in the case group (P<0.01). SLIT was effective in 85% of children with allergic rhinitis one after treatment vs 100% two years after treatment. Asthma control was observed in 76% of the asthmatic patients one after treatment vs 92% two years after treatment.

CONCLUSIONSSLIT is effective for allergic rhinitis and asthma in children, and the treatment period of two years seems to be superior to one year. The mechanism of action of SLIT for the treatment of allergic rhinitis and asthma may be associated with inhibition of IL-17 expression and promotion of IL-35 expression.