This has been documented in patients with granulomatosis with polyangiitis (a rare disease characterized by vasculitis), in which IL-15 trans-presented by monocytes/macrophages contributes to the survival and proliferation of NKG2D-expressing CD4+ T cells, which are the main mediators of the resulting endothelial cell damage[59]. Here, KLRK1 is linked to granulomatosis with polyangiitis.