Doi Takaaki, Mizukawa Yoshiko, Shimoda Yurie, Yamazaki Yoshimi, Shiohara Tetsuo
Department of Dermatology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
Department of Dermatology, Kyorin University School of Medicine, Mitaka, Tokyo, Japan.
J Invest Dermatol. 2017 Jan;137(1):151-158. doi: 10.1016/j.jid.2016.08.031. Epub 2016 Sep 17.
Although a marked rise in the prevalence of allergic diseases over the past few decades may be related to environmental factors in industrialized countries, evidence for the protective effect of humidity on the barrier function of the skin is still awaited. We asked whether an increase in the water content of stratum corneum at the site of hapten application had a strong impact on the magnitude of contact hypersensitivity (CHS). The magnitude of CHS, induced by either lipid-soluble or water-soluble hapten, was inversely correlated with the water content of stratum corneum at the hapten application site in the elicitation phase. An increase in the water content induced by exposure to high humidity for 6 hours was sufficient to ameliorate the magnitude of CHS even in mice with the genetic defect in attenuating the CHS responses, such as flaky tail mice. The reduced CHS was associated with downregulation of IL-1α, IL-4, and IFN-γ mRNA expression. Epicutaneously applied hapten can penetrate more readily through the stratum corneum with lower water content than that with higher water content, even after tape-stripping. These findings indicate that increased levels of water in the stratum corneum serve to ameliorate the CHS beyond the genetic effects.
尽管在过去几十年中，工业化国家过敏性疾病的患病率显著上升可能与环境因素有关，但湿度对皮肤屏障功能的保护作用仍有待证实。我们探讨了在半抗原应用部位角质层含水量的增加是否对接触性超敏反应（CHS）的程度有强烈影响。在激发阶段，由脂溶性或水溶性半抗原诱导的CHS程度与半抗原应用部位角质层的含水量呈负相关。即使是对CHS反应减弱存在基因缺陷的小鼠（如片状尾巴小鼠），暴露于高湿度环境6小时所导致的含水量增加也足以减轻CHS的程度。CHS的减轻与IL-1α、IL-4和IFN-γ mRNA表达的下调有关。即使经过胶带剥离，经皮应用的半抗原在含水量较低的角质层中比在含水量较高的角质层中更容易渗透。这些发现表明，角质层中水分含量的增加有助于减轻CHS，其作用超过了基因效应。
