Investigating the transition of psoriasis to psoriatic arthritis: A focus on T cells, lymphatics and their interplay

This thesis aimed to explore LECs and T cells and their crosstalk in psoriatic disease in general, and their possible roles in progression of psoriasis to PsA. We found that T cells, in particular CCR6+ Th memory cells, proportionally differ between the diseases, but also have unique features which could drive pathogenesis and progression of psoriasis to PsA. LECs, lining the lymphatic vasculature, are central players in the immune response and can contribute to the pathogenesis of psoriasis and PsA in multiple ways. Differences between LECs from psoriasis and PsA patients also suggest different molecular mechanisms in these diseases despite no macroscopic differences between psoriatic plaques from psoriasis and PsA patients. Further research to intervening in pathogenic T cell and LEC interactions might help in further improving patients' outcomes. Further understanding of underlying mechanisms and cells, such as LECs and T cells, driving progression of psoriasis to PsA hopefully will lead to the ultimate goal of preventing psoriasis progression to PsA.