Is psoriatic arthritis a dissemination of cutaneous psoriatic TRM cells? Role of tissue-resident memory T cells (TRM) in psoriatic disease.

Tissue resident memory T cells (TRM) cells are a recently defined subtype of nonrecirculating memory T cells with longevity and protective functions in peripheral tissues. The discovery of T cells resident in diverse tissues has altered our understanding of adaptive immunity with respect to site-specific immune response. For frontline defense against infections, TRM cells are essential. Accumulating evidence also implies that TRM cells are likely to contribute to the relapse and chronicity in autoimmune diseases, including psoriatic disease. A number of studies have shown the relationship between the pathogenesis of psoriasis and skin-resident memory T cells. Here, we discussed recent insights into the generation, homing, survival, and retention of TRM cells and shared our perspectives on the functions of TRM cells in the recurrence of psoriasis and psoriatic arthritis (PsA). This review summarizes the role of TRM cells in the pathology of psoriasis/PsA, with a view to develop potential novel therapies and therapeutic targets.