title: Relationship between serum 25-hydroxyvitamin D and interleukin-31 levels, and the severity of atopic dermatitis in children.
abstract: OBJECTIVE
  Atopic dermatitis (AD) is a chronic inflammatory relapsing skin disorder. Vitamin D plays a pivotal role in the development of AD, and interleukin (IL) 31 is known to be related to pruritus in AD. The aim of our study was to determine whether 25-hydroxyvitamin D (25(OH)D) levels are related to IL-31 levels or to the severity of AD.
  
  
  METHODS
  We enrolled 91 children with AD and 32 control subjects without history or symptoms of allergic diseases. Blood was drawn to evaluate complete blood cell count, total eosinophil count (TEC), and total IgE, specific IgE to common allergens, 25(OH)D, and IL-31 levels. Serum 25(OH)D and IL-31 levels were measured using high-performance liquid chromatography and enzyme-linked immunosorbent assay, respectively. The scoring atopic dermatitis (SCORAD) index was used to evaluate the severity of AD.
  
  
  RESULTS
  The mean 25(OH)D level was significantly lower in the AD group than in the control group; 25(OH)D decreased greatly in the moderate and severe AD groups compared with the mild AD group. Children with atopic sensitization showed significantly lower 25(OH)D levels than nonatopic children. However, serum IL-31 levels were not related to AD group, SCORAD index, or 25(OH)D levels. The SCORAD index was inversely correlated with serum 25(OH)D level and positively correlated with TECs and total IgE levels. Children with moderate and severe AD had significantly higher TECs than children with mild AD.
  
  
  CONCLUSIONS
  Vitamin D is related to the severity of AD independently of IL-31.
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Bo Ram
authors: BR
authors: Cheon
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jeong Eun
authors: JE
authors: Shin
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Yun Ji
authors: YJ
authors: Kim
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jae Won
authors: JW
authors: Shim
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Deok Soo
authors: DS
authors: Kim
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Hye Lim
authors: HL
authors: Jung
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Moon Soo
authors: MS
authors: Park
authors: Department of Pediatrics, Kangbuk Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jung Yeon
authors: JY
authors: Shim
keywords: 25-hydroxyvitamin D; Atopic dermatitis; Atopic sensitization; Child; Interleukin-31