PDCD1 and psoriasis: To investigate this hypothesis, we evaluated whether T cells expressing markers of T cell receptor (TCR)-mediated activation, such as 4-1BB or terminal differentiation, PD-1, TIM-3 and NKG2D, accumulate systemically in a mouse model of recurrent psoriasis and we explored their potential role in endothelial dysfunction and vascular inflammation (30, 31).