150 eligible patients will be enrolled on the basis of inclusion criteria. Patients will be divided in two groups: 1) Group 1 age between 6 and 18 years; 2) Group 2 older than 18 years. Patients will be randomly assigned to the treatment or placebo arm.Patients randomized in the GSH arm will receive a dosage of 10 mg/kg bid over a 12 months period.