Individuals with abnormal AAT phenotypes have a significantly higher chance of having ANCA (particularly PR3),30,31,34 and low serum AAT levels are associated with anti-PR3 in patients with severe vasculitis and pulmonary hemorrhage.33 Abnormal AAT phenotypes have also been associated with severity of ANCA associated disease.35 Here, PRTN3 is linked to Pulmonary hemorrhage.