Background: An important issue in sublingual immunotherapy (SLIT) is how to improve efficacy.
Objective: To compare the clinical efficacy of SLIT with vitamin D supplementation with placebo in children with allergic rhinitis. Secondary end points included lung function, exhaled nitric oxide concentration, methacholine bronchial provocation test, and serum level of calcifediol (25[OH]D).
Methods: Fifty children, ages 5-12 years, sensitive to grass pollen, with allergic rhinitis (eight patients had concomitant asthma) participated in a 5-month prospective, randomized, double-blind, placebo-controlled trial. Children received a 5-grass pollen sublingual 300 IR tablet with either vitamin D 1000 IU daily supplementation or placebo.
Results: When compared with the placebo group, SLIT plus vitamin D group therapy was more effective in the reduction of nasal symptoms (p = 0.04), asthma symptoms (p = 0.001), and the combined symptom-medication score (p = 0.001); there was no significant difference between the groups in medication and ocular scores. We observed a significant improvement of forced expiratory volume in 1 second (vitamin D group, p = 0.014; placebo group, p = 0.015) and the proportion of a person's vital capacity expired in the first second of forced expiration levels (vitamin D group, p = 0.004; placebo group, p < 0.001), within both groups, between visits. Fractional exhaled nitric oxide and provocative dose producing a 20% fall in forced expiratory volume in 1 second results did not statistically significantly differentiate the study participants in terms of receiving SLIT along with vitamin D or placebo. We showed a significant increase in calcifediol in the SLIT plus vitamin D group as well as in SLIT plus placebo group.
Conclusions: Vitamin D supplementation combined with grass-specific SLIT was more effective in the reduction of nasal and asthma symptoms. Vitamin D supplementation combined with SLIT provides an effective and well-tolerated new immunotherapy modality for treating children with allergic rhinitis. A 5-grass pollen sublingual 300 IR tablet was effective in both studied groups and also in children with comorbid mild asthma.