Skin is a fundamental component of our host defense system that provides a dynamic physical and chemical barrier against pathogen invasion and environmental insults. Cutaneous barrier function is mediated by complex interactions between structural cells such as keratinocytes and diverse lineages of immune cells. In contrast to the protective role of these intercellular interactions, uncontrolled immune activation can lead to keratinocyte dysfunction and psoriasis, a chronic inflammatory disease affecting 2% of the global population. Despite some differences between human and murine skin, animal models of psoriasiform inflammation have greatly informed clinical approaches to disease. These studies have helped to identify the interleukin (IL)-23-IL-17 axis as a central cytokine network that drives disease. In addition, they have led to the recent description of long-lived, skin-resident innate lymphocyte and lymphoid cells that accumulate in psoriatic lesions. Although not completely defined, these populations have both overlapping and unique functions compared to antigen-restricted αβ T lymphocytes, the latter of which are well-known to contribute to disease pathogenesis. In this review, we describe the diversity of innate lymphocytes and lymphoid cells found in mammalian skin with a special focus on αβ T cells, Natural Killer T cells and Innate Lymphoid cells. In addition, we discuss the effector functions of these unique leukocyte subsets and how each may contribute to different stages of psoriasis. A more complete understanding of these cell types that bridge the innate and adaptive immune system will hopefully lead to more targeted therapies that mitigate or prevent disease progression.

皮肤是我们宿主防御系统的基本组成部分，可为病原体入侵和环境侵害提供动态的物理和化学屏障。皮肤屏障功能是由结构细胞（例如角质形成细胞）与免疫细胞的不同谱系之间的复杂相互作用介导的。与这些细胞间相互作用的保护作用相反，不受控制的免疫激活可导致角质形成细胞功能障碍和牛皮癣，这是一种慢性炎性疾病，影响了全球2％的人口。尽管人类皮肤和鼠类皮肤之间存在一些差异，但牛皮癣样炎症的动物模型已大大有助于疾病的临床研究。这些研究有助于确定白介素（IL）-23-IL-17轴是驱动疾病的中央细胞因子网络。此外，他们导致了最近的描述，即在银屑病病灶中积累的长寿命，皮肤驻留的先天淋巴细胞和淋巴样细胞。尽管没有完全定义，但与受抗原限制的αβT淋巴细胞相比，这些种群既具有重叠功能又具有独特的功能，众所周知，后者受累会导致疾病发病。在这篇综述中，我们描述了在哺乳动物皮肤中发现的先天淋巴细胞和淋巴样细胞的多样性，特别着重于αβT细胞，天然杀伤性T细胞和先天淋巴样细胞。此外，我们讨论了这些独特的白细胞子集的效应子功能，以及每个子集如何影响牛皮癣的不同阶段。