About the study
Blood stem cells can produce red blood cells (which carry oxygen), white blood cells of the
immune system (which fight infections) and platelets (which help the blood clot).
Patients with sickle cell disease produce abnormal red blood cells. A blood stem cell
transplant from a donor is a treatment option for patients with severe sickle cell disease.
The donor can be healthy or have the sickle cell trait. The blood stem cell transplant will
be given to the patient as an intravenous infusion (IV). The donor blood stem cells will then
make normal red blood cells – as well as other types of blood cells – in the patient. When
blood cells from two people co-exist in the patient, this is called mixed chimerism.
Most children are successfully treated with blood stem cells from a sibling (brother/sister)
who completely shares their tissue type (full-matched donor). However, transplant is not an
option for patients who (1) have serious medical problems, and/or (2) do not have a
full-matched donor. Most patients will have a relative who shares half of their tissue type
(e.g. parent, child, and brother/sister) and can be a donor (half-matched or haploidentical
Adult patients with severe sickle cell disease were successfully treated with a half-matched
transplant in a clinical study. Researchers would like to make half-matched transplant an
option for more patients by (1) improving transplant success and (2) reducing
This research transplant is being tested in this Pilot study for the first time. It is
different from a standard transplant because:
1. Half-matched related donors will be used, and
2. A new combination of drugs (chemotherapy) that does not completely wipe out the bone
marrow cells (non-myeloablative treatment) will be used to prepare the patient for
3. Most of the donor CD4+ T cells (a type of immune cells) will be removed (depleted)
before giving the blood stem cell transplant to the patient to improve transplant
It is hoped that the research transplant:
1. Will reverse sickle cell disease and improve patient quality of life,
2. Will reduce side effects and help the patient recover faster from the transplant,
3. Help the patient keep the transplant longer and
4. Reduce serious transplant-related complications.