Agrawal Rachana, Wisniewski Julia A, Woodfolk Judith A
Curr Probl Dermatol. 2011;41:112-124. doi: 10.1159/000323305. Epub 2011 May 12.
Regulatory T (T(reg)) cells play a pivotal role in immune suppression and are integral to the control of allergic responses. The chronic inflammatory skin condition atopic dermatitis (AD) is severest in patients who are sensitized to allergens from diverse sources including foods, pollens and animal danders, as well as skin-colonizing organisms. These individuals typically present with eczematous skin eruptions in early childhood, and evolution of the disease is thought to reflect an underlying dysregulated T-cell response to allergens that manifests as a Th2 response. Studying T(reg) cells in the context of AD from infancy into adulthood could yield insight into their role in disease pathogenesis and reveal new strategies for exploiting these cells for therapeutic purposes. Such studies are challenging in humans owing to the heterogeneous nature of T(reg) cells, lack of a reliable surface marker, and the paucity of knowledge surrounding the emergence of specialized T cells in early life. Moreover, the blurred distinction between activated effector T cells and T(reg) cells further complicates studies in the context of inflammatory disorders such as AD. There is emerging evidence to suggest that T(reg) cells can convert to Th2 cells and that this pathway is bidirectional. This phenomenon may be a double-edged sword with important implications not only for subverting T(reg) cells in disease, but also for potential treatments designed to amplify these cells in order to suppress the allergic inflammatory cascade in AD.
调节性T（T(reg)）细胞在免疫抑制中起关键作用，是控制过敏反应不可或缺的一部分。慢性炎症性皮肤病特应性皮炎（AD）在对多种来源的过敏原敏感的患者中最为严重，这些过敏原包括食物、花粉、动物皮屑以及皮肤定植微生物。这些个体通常在幼儿期出现湿疹性皮肤疹，疾病的演变被认为反映了对过敏原的潜在T细胞反应失调，表现为Th2反应。从婴儿期到成年期研究AD背景下的T(reg)细胞，可能有助于深入了解它们在疾病发病机制中的作用，并揭示利用这些细胞进行治疗的新策略。由于T(reg)细胞的异质性、缺乏可靠的表面标志物以及对早期生命中特化T细胞出现的了解匮乏，此类研究在人类中具有挑战性。此外，活化的效应T细胞与T(reg)细胞之间的界限模糊，进一步使AD等炎症性疾病背景下的研究复杂化。有新证据表明T(reg)细胞可转化为Th2细胞，且该途径是双向的。这种现象可能是一把双刃剑，不仅对疾病中T(reg)细胞的破坏有重要影响，而且对旨在扩增这些细胞以抑制AD中过敏性炎症级联反应的潜在治疗也有重要影响。
