Analysis of factors that regulate effector T cell and regulatory T cell recruitment to the skin

在这项研究中，我们研究了哪些因素可以决定炎症部位效应T细胞（Teff）和调节T细胞（Treg）之间的平衡。在自发消退的固定药疹（FDE）病变中，大量检测到表达高水平IL-16的肥大细胞，从而诱导Treg募集到炎症部位。相反，SJS/TEN病变中表达IL-16的肥大细胞缺乏，表现出严重的免疫病理，使得Treg无法迁移到炎症部位。另一方面，通过诱导Treg募集，表达IL-16的肥大细胞的丰度不利于肿瘤的消退。反复应用能够刺激TLR7/8的咪喹莫特导致肥大细胞IL-17表达增加，Treg/Teff比值显著降低，这与肿瘤消退有关。因此，炎症部位Treg和Teff之间的平衡可以由病变内的肥大细胞决定：如果它们优先产生IL-16，病变会自发消退；但如果它们产生IL-17，免疫病理就会随之而来。

In this study, we investigated which factors can determine the balance between effector T cells (Teff) and regulator T cells (Treg) in the inflammatory sites. In fixed drug eruption (FDE) lesions that spontaneously resolve, mast cells expressing high levels of IL-16 are abundantly detected, thereby inducing Treg recruitment to the inflammatory site. In contrast, the paucity of mast cells expressing IL-16 in the SJS/TEN lesions that exibit severe immunopathology made Treg impossible to migrate into the inflammatory site. On the other hand, the abundance of mast cells expressing IL-16 was detrimental to tumor regression through the induction of Treg recruitment. Repeated application of imiquimod able to stimulate TLR7/8 caused an increase in IL-17 expressing mast cells and a profound decrease in the Treg/Teff ratio, which was associated with tumor regression. Thus, the balance between Treg and Teff in the inflammatory site can be determined by mast cells resident in the lesion: if they preferentially produce IL-16, the lesions spontaneously resolve; but if they produce IL-17, immunopathology ensues.