Department of Dermatology, Sexually Transmitted Diseases and Clinical Immunology, The University of Warmia and Mazury, Al. Wojska Polskiego 30 10-229 Olsztyn, Poland.
Department of Rheumatology, Municipal Hospital in 10-229 Olsztyn, Poland.
Int J Mol Sci. 2020 Jan 17;21(2):625. doi: 10.3390/ijms21020625.
The natural course of psoriasis is the appearance of new lesions in the place of previous ones, which disappeared after a successful therapy. Recent studies of psoriasis etiopathogenesis showed that after psoriatic plaques have disappeared, in healthy skin we can still find a trace of inflammation in the form of tissue resident memory cells (TRM). They are originally responsible for protection against viral and bacterial infections in non-lymphatic tissues. In psoriatic inflammation, they are characterized by heterogeneity depending on their origin. CD8+ T cells TRM are abundantly present in psoriatic epidermis, while CD4+ TRM preferentially populate the dermis. In psoriasis, epidermal CD8+ TRM cells express CLA, CCR6, CD103 and IL-23R antigen and produce IL-17A during ex vivo stimulation. However, CD4+ CD103+ TRM can also colonize the epidermis and produce IL-22 during stimulation. Besides T cells, Th22 and epidermal DCs proved that epidermal cells in healed skin were still present and functioning after several years of disease remission. It explains the clinical phenomenon of the tendency of psoriatic lesions to relapse in the same location and it allows to develop new therapeutic strategies in the future.
银屑病的自然病程是在先前皮损部位出现新的皮损，而在成功治疗后这些皮损会消失。最近对银屑病发病机制的研究表明，在银屑病斑块消退后，在健康的皮肤中，我们仍然可以找到以组织驻留记忆细胞（TRM）形式存在的炎症痕迹。它们最初负责保护非淋巴组织免受病毒和细菌感染。在银屑病炎症中，根据其起源，它们具有异质性。CD8+T 细胞 TRM 在银屑病表皮中大量存在，而 CD4+TRM 则优先分布在真皮中。在银屑病中，表皮 CD8+TRM 细胞在体外刺激时表达 CLA、CCR6、CD103 和 IL-23R 抗原，并产生 IL-17A。然而，CD4+CD103+TRM 也可以在刺激过程中定植于表皮并产生 IL-22。除 T 细胞外，Th22 和表皮 DC 证明，在疾病缓解数年后，愈合皮肤中的表皮细胞仍然存在并发挥功能。这解释了银屑病皮损在同一部位复发的临床现象，并为未来开发新的治疗策略提供了依据。
