Relationship between serum interleukin-31/25-hydroxyvitamin D levels and the severity of atopic dermatitis in children

ABSTRACT

PURPOSE: Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease. Vitamin D and interleukin-31 (IL-31) are known to be related to the pathogenesis of AD with pruritus. The purpose of this study was to investigate the relationship between serum levels of 25-hydroxyvitamin D (25(OH)D) and IL-31 and the disease severity of AD in children with AD. METHODS: We recruited 160 children with AD and 42 controls. We used the SCORing Atopic Dermatitis (SCORAD) index to measure the severity of AD. Serum IL-31 and 25(OH)D levels were assayed using enzyme-linked immunosorbent assay and high-performance liquid chromatography, respectively. Serum levels of total IgE, specific IgE to common allergens and peripheral blood total eosinophil count were carried out in children with AD. RESULTS: Serum IL-31 level was significantly higher in AD group compared to control group and 25(OH)D level was significantly lower in AD group than control group. Serum IL-31 level showed the highest level in severe AD group followed by moderate and mild AD group, whilst serum 25(OH)D level was the lowest in severe AD group compared to moderate and mild AD group. There was no difference in serum IL-31 level between AD group and nonatopic dermatitis group. IL-31 level was positively correlated with subjective SCORAD index indicating pruritus in children with AD, and 25(OH)D was inversely correlated with SCORAD index. CONCLUSION: IL-31 and vitamin D may be related to the pathogenesis of AD, especially with regard to the pruritus.