ADA2 and X-linked lymphoproliferative syndrome: In recent years, vasculitis has been described as a feature of various forms of PID, including those with pathogenic STAT1 gain-of-function variants, adenosine deaminase 2 (ADA2) deficiency, X-linked lymphoproliferative syndrome (XLP) type 1, Wiskott-Aldrich-syndrome (WAS), TAP1/2 deficiency, complement deficiency, and NOD2 deficiency (15–21).