Relationship of serum vitamin D and interleukin-31 levels to allergic or nonallergic rhinitis in children

ABSTRACT

PURPOSE: Serum vitamin D (25-hydroxyvitamin D, 25[OH] D) and interleukin-31 (IL-31) are related to atopic dermatitis, but their relationship with allergic rhinitis is unclear. The purpose of this study was to compare the levels of serum IL-31 and 25 (OH) D between the allergic rhinitis (AR), nonallergic rhinitis (NAR), and control groups and to investigate the relationship between IL-31 and 25 (OH) D. METHODS: We recruited 59 children with only rhinitis and 33 controls without any allergic diseases. Serum IL-31 and 25(OH) D levels were assayed using an enzyme-linked immunosorbent assay and high-performance liquid chromatography, respectively. The patients were considered to have atopic sensitization if the levels of serum specific IgE to inhalant allergens as assessed using immunoCAP were ≥0.35 IU/mL or if they tested positive for one or more allergens by the skin prick test. RESULTS: Of children with rhinitis, 25 had nonatopy (NAR), and 34 children had atopy (AR). Serum 25(OH) D levels were significantly lower in the rhinitis group than in the control group, while there was no significant difference serum 25(OH) D levels between the AR and NAR groups. Children with rhinitis demonstrated higher serum IL-31 levels than controls; however, there was no difference in serum IL-31 levels between the AR and NAR groups. Serum 25(OH) D levels were inversely correlated with serum IL-31 levels and blood eosinophil counts. On the other hand, serum 25(OH) D levels were not correlated with total serum IgE levels. CONCLUSION: Serum 25(OH) D and IL-31 may play a role in the pathogenesis of rhinitis via mechanisms other than IgE-related pathway.