Inclusion Criteria

Inclusion criteria:

- All patients must:

- Have related donors who are identical at 6 human leukocyte antigens (HLA) loci
(A, B and DR) by molecular typing

- Have a performance status from 0-2

- Give written informed consent

- Patients with sickle cell disease should have 1 or more of the following:

- Acute chest syndrome requiring recurrent hospitalization or exchange transfusion

- Nonhemorrhagic stroke or central nervous system event lasting longer than 24
hours

- Recurrent vaso-occlusive pain (2 episodes or more per year) or recurrent
priapism

- Sickle nephropathy (moderate or severe proteinuria or a glomerular filtration
rate 30-50 percent of normal predicted value)

- Bilateral proliferative retinopathy and major visual impairment in at least 1
eye

- Osteonecrosis of multiple joints

- Patients with thalassemia should have 1 or more of the following:

- Transfusion dependence, defined as a transfusion requirement of greater than or
equal to 6 units of packed red blood cells over the past 12 months

- Iron overload, defined as serum ferritin greater than 500 mcg/L in the absence
of infection or biopsy-proven iron overload

- Presence of 2 or more alloantibodies against red cell antigens

Exclusion criteria:

- Pregnancy

- Acute hepatitis (transaminases greater than 3 times the normal value)

- Cardiac ejection fraction less than 30 percent

- Severe renal impairment (glomerular filtration rate less than 30 percent of predicted
normal value)

- Severe residual functional neurologic impairment (other than hemiplegia alone)

- Seropositivity for the human immunodeficiency virus (HIV)