| ObjectTo evaluate the potential importance of human IL-31 in the pathogenesis of atopic dermatitis and to explore its correlation with the severity of disease and pruritus as well as the probable mechanisms.MethodsTwenty-two children with AD and Twenty-two age mached healthy controls were recruited in this study. Parameters such as SCORAD, scores of pruritus and sleep loss, total serum IgE, blood eosinophil count were assessed. Peripheral blood mononuclear cells were isolated and stimulated with or without SEB for 24 hours. Expression of IL-31 mRNA in PBMCs was evaluated by means of quantitative real-time PCR. IL-31RA level and distribution were also detected in skin biopsy specimens by using immunohistochemistry.ResultsIL-31 mRNA expression in AD children was significantly upregulated, which is much higher than that of in normal controls (P<0.05). We also observed that stapgylococal enterotoxin B can induce IL-31 expression rapidly in healthy individuals. However, there is no statistical difference in terms of IL-31 expression was identified between IAD and EAD. In AD children, the IL-31 expression levels correlated positively with the severity of disease and the degree of pruritus (r=0.491, P<0.05; r=0.544, P<0.05 respectively). IL-31RA positive staining was found mainly in cytoplasm of keratinocytes and was more pronounced in AD skin compared with that in heathy controls (P<0.001). IL-31RA positive staining was also observed in nerve fiber bundle, tunic of Meissner's corpuscles and Pacinian corpuscle in the dermis of AD skin lesion.ConclusionIL-31 plays an important role in the pathogenesis of AD, which may act in a way independent of serum total IgE. As a regulator of IL-31 producing, SEB can induce IL-31 rapid expression in PBMCs of healthy controls.IL-31 may not be the major immunologic differences between IAD and EAD. However, it contributes to the development of prutitus in AD and could serve as a marker of disease severity in AD. |
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