Autologous vs. Allogenic Hematopoietic Stem Cell Transplant
Stem cell transplants - autologous and allogenic
Autologous | Allogenic
Written by: Anurag Saraf, MD, Nirmala Saraf, MD, and Nancy Mills MD
The first successful bone marrow transplant was performed in 1957 by Dr. E. Donnall Thomas in a patient with acute leukemia. For his research Dr. Thomas subsequently won the Nobel Prize in physiology and medicine. The success of this transplant was in part due to the fact that it was a “syngeneic transplant”. The donor was the patient’s monozygotic twin! (7)
Traditionally, stem-cell transplants had been collected through the bone marrow, and therefore were referred to as "bone marrow transplant". However, today most transplants can be collected through pheresis of the peripheral blood using CD34 as a differentiating marker or from cord blood; therefore the name hematopoietic stem cell transplant is now more appropriate.
Hematopoietic stem cell transplant involves the administration of healthy hematopoietic stem cells to patients with dysfunctional bone marrow (from disease) or with depleted bone marrow (either by disease or by purposeful high-dose chemotherapy or total body irradiation)(6).
Indications for hematopoietic stem cell transplant might include malignancies (including multiple myeloma, Hodgkin and Non-Hodgkin lymphomas, acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndrome, chronic myeloid leukemia, chronic lymphocytic leukemia, myelofibrosis and polycythemia vera), other solid tumor malignancies (including testicular tumors refractory to chemotherapy) and non-malignant diseases including aplastic anemia, severe combined deficiency syndrome, thalassemia, sickle cell anemia and possibly autoimmune disorders such as progressive multiple sclerosis, systemic sclerosis and systemic lupus erythematosus. (6)
Autologous Hematopoietic Stem Cell Transplant
Autologous Hematopoietic Stem Cell Transplant
Autologous Stem Cell Transplant
Autologous Hematopoietic Stem Cell Transplant (Auto HSCT) involves an induction therapy to eradicate a patient’s hematopoietic system and then rescue it with their own stem cells. It is used in the setting of blood cancers (e.g. leukemia, lymphoma), as well as some autoimmune conditions. Auto HSCT should be differentiated from Allogeneic HSCT, which involves transplanting a donor’s stem cells, rather than the patient's own stem cells, after hematopoietic ablation.
Efficacy of Auto HSCT on the disease process is thought to be primarily from the induction therapy. High-dose chemotherapy and/or radiation therapy is used to eradicate as many malignant cells as possible, including microscopic and resistant cells. Higher dose therapy can be used because the bone marrow will be rescued with autologous stem cells. This is different from Allo HSCT which has the second effect of the Graft-versus-leukemia (GVL) effect, where any microscopic and/or resistant disease after myeloablation can continue to be attacked by donor immune system, an effect seen even weeks to months after transplant. Auto HSCT has no GVL effect, and the primary treatment effect is from the induction therapy. Advantages of Auto HSCT over Allo HSCT include patients not having to find a donor and not experiencing graft-versus-host disease. Elderly and frail patients who cannot tolerate the myeloablative procedure are not considered good candidates for Auto HSCT.
Allogeneic Hematopoietic Stem Cell Transplant
allogeneic hematopoietic stem cell transplant
allogeneic stem cell transplant
Allogeneic hematopoietic stem cell transplant (allo-HSCT) involves the transplantation of stem cells from a healthy person into the body of a patient who has undergone induction chemotherapy or radiation therapy (myeloablation therapy, reduced-intensity conditioning therapy) to treat blood cancers (leukemia, lymphoma) and some autoimmune conditions. Allo-HSCT is different than autologous HSCT, which involves transplanting the patient’s own cells after chemotherapy and radiation.
Allo-HSCT is believed to have two effects on disease. First, the myeloablation itself eradicates the malignancy. Second, the donor transplant has some graft-versus-leukemia (GVL) effect, in which any microscopic and/or resistant disease after myeloablation can continue to be attacked; this effect can remain even weeks to months after transplant. For certain diseases, particularly certain leukemias, the GVL effect may be the strongest, so patients can get less intensive induction protocols (often called reduced-intensity conditioning therapy or non-myeloablation induction therapy), particularly elderly patients who cannot tolerate myeloablation that well. In contrast, auto-HSCT has no GVL effect, and the primary treatment effect comes only from the induction therapy; however, patients do not have to be concerned about finding a donor or experiencing graft-versus-host disease (GVHD).
Allo-HSCT given at transplant is for rescue of hematopoietic function after induction therapy; it allows patients to engraft bone marrow stem cells and produce normal hematopoietic function.
Complications of Allo-HSCT
GVHD, in which transplanted cells attack the host's organs, is a major complication of allo-HSCT. It is particularly prevalent in the gastrointestinal tract, skin, and eyes. Treatment often involves immunosuppression (either with a chronic course of steroids or other immunomodulators [e.g., tacrolimus]). Acute GVHD is seen within the first weeks to months after transplant, whereas chronic GVHD can last for several years afterwards. Patients undergoing auto-HSCT do not develop GVHD.
Oncology definitions in the FibonacciCOMPENDIUM
Autologous Stem Cell Transplant
Allogenic Hematopoietic Stem Cell Transplant
#InBrief #Oncology #FibonacciCOMPENDIUM
1. Leukemia & Lymphoma Society 2019. "AUTOLOGOUS STEM CELL TRANSPLANTATION". (https://www.lls.org/treatment/types-of-treatment/stem-cell-transplantation/autologous-stem-cell-transplantation)
2. MSKCC 2019. "Autologous Transplantation". (https://www.mskcc.org/cancer-care/diagnosis-treatment/cancer-treatments/blood-stem-cell-transplantation/autologous)
3. Allogeneic stem cell transplantation. Leukemia & Lymphoma Society Web site. https://www.lls.org/treatment/types-of-treatment/stem-cell-transplantation/allogeneic-stem-cell-transplantation. Accessed August 21, 2019.
4. Autologous vs. allogenic stem cell transplants: what’s the difference? Insight from Dana Farber Cancer Institute Web site. https://blog.dana-farber.org/insight/2017/03/autologous-vs-allogenic-stem-cell-transplants-whats-the-difference/. March 6, 2017. Accessed August 21, 2019.
5. Sengsayadeth S, Savani BN, Blaise D, Malard M, Nagler A, Mohty M. Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT. Haematologica. 2015;100:859-869.
6. Khaddour K, Hana C, Mewawalla P. Hematopoietic Stem Cell Transplantation. StatPearls. Last Update: June 27, 2022.
7. Thomas ED, Lochte HL, Lu WC, Ferrebee JW. Intravenous infusion of bone marrow in patients receiving radiation and chemotherapy. N Engl J Med. 1957 Sep 12;257(11):491-6. [PubMed]
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