hematopoietic stem cell therapy
Monday 17 October 2011
HSCs possess the ability to self-renew and differentiate into all types of blood cells, especially those involved in the human immune system.
Thus, they can be used to treat blood and immune disorders.
Since human bone marrow (BM) grafting was first published in 1957, there have been significant advancements in HSCs therapy.
Following that, syngeneic marrow infusion and allogeneic marrow grafting were performed successfully.
HSCs therapy can also render its cure by reconstituting damaged blood-forming cells and restoring the immune system after high-dose chemotherapy to eliminate disease.
There are three types of HSCT:
Syngeneic transplantations occur between identical twins.
Autologous transplantations use the HSCs obtained directly from the patient and hence do not cause any complications of tissue incompatibility.
Allogeneic transplantations involve the use of donor HSCs, either genetically related or unrelated to the recipient.
To lower the risks of transplant, which include graft rejection and GVHD, allogeneic HSCT must satisfy compatibility at the HLA loci (i.e. genetic matching to reduce the immunogenicity of the transplant).
Mismatch of HLA loci would result in treatment-related mortality and higher risk of acute GVHD.
In addition to BM derived HSCs, the use of alternative sources such as umbilical cord blood (UCB) and peripheral blood stem cells (PBSCs) has been increasing.
In comparison with BM derived HSCs recipients, PBSCs recipients afflicted with myeloid malignancies reported a faster engraftment and better overall survival.
However, this was at the expense of increased rate of GVHD.
Also, the use of UCB requires less stringent HLA loci matching, although the time of engraftment is longer and graft failure rate is higher.