Stem Cell Therapy at World Class Hospitals in India
Hematopoietic stem cell transplantation (HSCT) is the transplantation of blood stem cells derived from the bone marrow (in this case known as Bone Marrow Transplantation). Stem cell transplantation is a medical procedure in the fields of haematology and oncology, most often performed for people with diseases of the blood, bone marrow, or certain types of cancer.
With the availability of the stem cell growth factors GM-CSF and G-CSF, most hematopoietic stem cell transplantation procedures are now performed using stem cells collected from the peripheral blood, rather than from the bone marrow. Collecting peripheral blood stem cells provides a bigger graft, does not require that the donor be subjected to general anesthesia to collect the graft, results in a shorter time to engraftment, and may provide for a lower long-term relapse rate. Hematopoietic stem cell transplantation remains a risky procedure with many possible complications; it has traditionally been reserved for patients with life-threatening diseases. While occasionally used experimentally in nonmalignant and non-hematologic indications such as severe disabling auto-immune disease and cardiovascular disease, the risk of fatal complications appears too high to gain wider acceptance.
Types of Stem Cell Transplantation
Autologous Hematopoietic Stem Cell Transplantation :In Autologous HSCT, the patient’s own hematopoietic cells are infused to reestablish bone marrow function after the administration of high-dose chemotherapy and/or radiation therapy. Because a major limitation to the use of allogeneic BMT is that only a few patients have an HLA-matched sibling donor, the use of autologous hematopoietic cells greatly increases the number of patients eligible for transplantation. Autologous transplantation can also be used safely in older patients because of the absence of GVHD, which is a major concern with older patients. Autologous hematopoietic cell transplantation is most commonly used to reestablish hematopoiesis after high-dose cancer chemotherapy or radiation therapy. This approach permits the use of antitumor agents in doses much higher than can be provided in a conventional therapy setting. Autologous HCT is most useful incircumstances where a correlation exists between increased therapy dose and tumor response, and where the dose-limiting feature of therapy is hematopoietic suppression.
Hematopoietic stem cells can be harvested directly from the bone marrow or collected by apheresis from the peripheral blood after stimulation with granulocyte colony stimulating factor (G-CSF). Peripheral blood progenitor cells (PBPCs) are preferable to bone marrow cells for transplantation due to quicker engraftment and a potential for less contamination of the infused cells with tumor cells. Apheresis is performed with a goal of collecting at least 2 x 10(6) CD34+ cells/kg.Peripheral blood progenitor cells (PBPCs) are cryopreserved in 5%Dimethylsulfoxide, to be thawed at the bedside at the time of infusion.A preparative (conditioning) regimen, consisting of chemotherapy with or without radiation therapy, is given to eradicate malignant cells prior to rescue of the hematopoietic system with a PBPC infusion. Approximately 24 hours after completion of the preparative chemotherapy, peripheral blood progenitor cells (PBPCs) are reinfused. A period of pancytopenia follows. Red blood cell and platelet transfusions are administered as necessary while hematopoietic colony-stimulating factors (ie, G-CSF) may be used to speed neutrophil engraftment. Neutrophil engraftment usually occurs by day 12 and platelet counts are expected to recover to greater than 20,000 by day 16.
Risks Associated with Stem Cell Transplantation
Patients who undergo SCT are at risk for bacterial, viral, and fungal infections, the time course of which varies in the post transplant period, according to the degree of immune deficiency and cytopenia induced by the transplantation procedure. As a result, prophylactic therapies to prevent infection including antiviral and antifungal drugs are recommended during the period of increased risk. In addition, all markers of potential infection must be investigated thoroughly.
Clinical Applications- Autologous Stem Cell Transplantation
1.Multiple Myeloma – Autologous transplant therapy can prolong survival when used as therapy for myeloma after induction therapy.
1.Non-Hodgkin lymphoma – Patients with aggressive non-Hodgkin’s lymphoma who have not been cured by first-line chemotherapy or have relapsed and in second remission can still be cured in about 40 to 50% of cases by Autologous SCT.
1.Hodgkin’s lymphoma – With Autologous transplantation, 5-year disease-free survival is 20 to 30% in patients who never achieve a first remission with standard chemotherapy and up to 60% for those transplanted in second remission.
1.Acute Myelogenous Leukemia – Autologous HCT therapy for selected subsets of patients with acute myelogenous leukemia (Eg- AML -M3).