Background: Atopic eczema (AE) is a common pruritic and chronically relapsing inflammatory skin disease in which cytokines seem to represent important factors in the pathogenesis.
Objectives: We aimed to investigate cytokine mRNA expression in the skin of patients with AE who underwent a course of ultraviolet A1 (UVA1) phototherapy.
Methods: We studied 21 patients diagnosed with extrinsic AE who were treated with a 6-week course of UVA1 phototherapy. Skin biopsies were taken from healthy controls (n=18) and patients with AE at baseline and after the last UVA1 exposure. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed for interleukin (IL)-4, IL-5, IL-10, IL-13 and IL-31.
Results: A significant reduction of the clinical scores was observed after treatment with UVA1. Except for IL-4, cytokine mRNA expression was significantly increased prior to phototherapy when compared with controls. mRNA levels of IL-4 and IL-10 before UVA1 did not significantly differ from levels observed after UVA1. However, a significant decrease of IL-5, IL-13 and IL-31 mRNA expression was observed following UVA1 treatment. IL-31 mRNA levels were even adjusted to the levels of healthy controls.
Conclusions: We have shown that the resolution of extrinsic AE lesions following phototherapy is accompanied by significant reduction of mRNA expression of IL-5, IL-13 and IL-31, supporting current concepts that these cytokines play a crucial role in the pathogenesis of extrinsic AE and possibly represent targets for phototherapy.