ADA2 and Autoimmunity: Whereas clinical features of vasculitis and mild immunodeficiency due to cytopenia and hypogammaglobulinemia are commonly observed in patients with ADA2 deficiency, autoimmunity has only rarely been described [1, 4–7].Thus, low ANA titers have been reported in 9 out of 45 ADA2-deficient patients [3], while hypergammaglobulinemia has been reported only in two siblings with additional IL-17RA deficiency [9].