? HHT is a rare autosomal dominant vascular dysplasia affecting multiple organs. In HHT, telangiectases or arteriovenous malformations (AVM) involve loss of the capillary network with direct connections between arteries and veins resulting in severe complications. These complications include bleeding or shunting of blood that can result in stroke, brain abscess, heart failure and severe refractory anemia. The primary objective of the study is to determine the safety and tolerability of PEG-Intron in severe complications related to HHT. Secondary objectives determine the efficacy of PEG-Intron in severe complications related to HHT, effects on quality of life, and basic fibroblast growth factor (bFGF). Methods include 3 groups with severe complications related to HHT treated with weekly subcutaneous injections of PEG-Intron 1 mcg/kg/week for 12 months. Group 1 includes iron deficiency or transfusion-dependent anemia due to bleeding from HHT; Group 2 includes hepatic involvement by HHT with high output heart failure; and Group 3 includes diffuse pulmonary AVMs with hypoxemia. Serial follow-up assessments include Group 1 with hemoglobin, number of transfusions, and number of telangiectases; Group 2 with cardiac index and liver computed tomography scanning; and Group 3 with partial pressure of oxygen on room air at rest, oxygen saturation at exercise, and shunt assessment; and all groups with assessment of quality of life and bFGF levels. Patients with HHT who have severe bleeding from HHT are disabled due to the unpredictable severity of bleeding episodes. In liver involvement due to HHT, no treatment options exist and patients are turned down for liver transplantation. Patients can die from refractory liver failure and heart failure. Patients with diffuse pulmonary involvement have significant hypoxemia and exercise tolerance may be affected with treatment. ? ?