CD8+ tissue-resident memory T cells triggered the erosion of oral lichen planus by the cytokine network

CD8⁺tissue-resident memory T (CD8⁺Trm) cells play key roles in many immune-inflammation-related diseases. However, their characteristics in the pathological process of oral lichen planus (OLP) are unclear. Therefore, we investigated the function of CD8⁺Trm cells in the process of OLP. Single-cell RNA sequencing profiling and spatial transcriptomics revealed that compared with non-erosive OLP, CD8⁺Trm cells, which were mainly distributed in the lamina propria close to the basement membrane, were increased and functionally more active by secreting multiple cytokines in patients with erosive oral lichen planus (EOLP), including IFN-γ, TNF-α, and IL17. And our clinical cohort of 1-year follow-up was also supported the above results in RNA level and protein level. In summary, this study provided a novel molecular mechanism for triggering OLP erosion by CD8⁺Trm cells to secrete multiple cytokines, and new insight into the pathological development of OLP.