Phase I/II Study of Retroviral-Mediated Transfer of Iduronate-2-Sulfatase Gene Into Lymphocytes of Patients With Mucopolysaccharidosis II (Mild Hunter Syndrome)

OBJECTIVES: I. Evaluate the safety and feasibility of treating mucopolysaccharidosis II (mild Hunter syndrome) by lymphocyte gene therapy. II. Determine the levels of iduronate-2-sulfatase enzyme in these patients attained by infusing increasing doses of lymphocytes transduced with a retroviral vector designed for insertion and expression of this iduronate-2-sulfatase gene (L2SN). III. Determine the duration of survival of these transduced cells in these patients. IV. Determine whether monthly infusion of L2SN-transduced lymphocytes accomplishes metabolic correction (as measured by glycosaminoglycan excretion), decrease in liver or spleen volume, any therapeutic effect upon cardiac and pulmonary dysfunction, or any other effects from treatment.