A German study investigated the relationship between a common haplotype of the IL-31 gene, interleukin 31 (IL-31) levels and different features of atopic dermatitis (AD) in a cohort of 73 adult AD patients. It was found that 26% of patients were positive for haplotype A of the IL-31 gene. These patients had increased IL-31 levels and had higher pruritus scores as measured by visual analogue scale over 2 years. However, no relation between haplotype A, SCORing Atopic Dermatitis (SCORAD) index, total or specific immunoglobulin E levels were seen over 2 years. The relationship between haplotype A and serum IL-31 levels may be due to activation of the promoter region. IL-31 variants ...