Abstract
Activated phosphoinositide 3-kinase delta syndrome (APDS) is an inborn error of immunity with heterogeneous clinical manifestations of infections, immune dysregulation, autoimmunity; lymphoproliferation; and malignancy. Immune complex-mediated vasculitides have not yet been described in APDS patients. Here we offer a case series of three patients with APDS who have refractory IgA vasculitis (also called Henoch-Schönlein purpura), a form of immune complex-mediated vasculitis that activates complement and attracts neutrophils, macrophages and eosinophils to cause local tissue injury. Leniolisib is an inhibitor of PI3K p110δ and an FDA-approved treatment for APDS. IgA vasculitis resolved upon treatment with leniolisib. Patients with immune dysregulation including IgA vasculitis should be screened for APDS.