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Frequently Asked Questions
  1. What is bone marrow?
  2. What are the functions of blood cells?
  3. How does Hematopoietic Cell Transplantation (HCT) work?
  4. Why are marrow transplants used?
  5. What are the eligibility criteria for a transplant?
  6. Who determines when a person is eligible?
  7. How is the healthy marrow replaced or transplanted?
  8. How are transplants performed?
  9. How is the bone marrow or the Hematopoeitic Stem Cells (HSC) collected?
  10. How is the collection stored?
  11. How does it feel after the marrow is harvested?
  12. Once harvested, when does the transplantation occur?
  13. What happens after the transplant?
  14. How is the patient protected during this time of vulnerability?
  15. How is the transplant's success evaluated?
  16. What is the average recovery period for transplantation patients?
  17. What is the success rate for marrow transplant?
  18. Does the absence of disease mean cure?
  19. What is HLA or Human Leukocyte Antigens?
  20. What are the techniques used for typing/comparing donors?
  21. What are the different types of transplants performed at AUBMC?




















  1. What is Bone Marrow?
    Within the large bones are found spongy tissues called the bone marrow. Specifically, the bone marrow in the sternum, skull, hips, ribs, and spine contains stem cells. Stem cells are the very young cells that mature and develop into three types of cells: RBC's (red blood cells or erythrocytes), WBC's (white blood cells or leukocytes), and platelets (clotting cells). These are the body's blood components and main agents of the immune system.
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  2. What Are the Functions of Blood Cells?
    A deficiency in any type of normal white blood cell (WBC) may result in an increased susceptibility to infection, as well as in a reduced resistance to any number of diseases. Leukocytes are key players in the defense mechanism of the body against disease-producing bacterial, viral, and fungal infections. They are made up of three lines of WBC's: granulocytes, lymphocytes, and a cell line that includes monocytes and macrophages.

    Neutrophils (account for 60% of all white cells), eosinophils, and basophils are the subdivisions that form the granulocytes. They work by increasing their numbers at times of infection to engulf and destroy foreign substances.

    Defense against bacterial infection is also the job of the monocytes. Once this task is completed, they quickly return to their original pre-infection number.

    Lymphocytes consist of two cell types combining their efforts to regulate the immune response: T-cells and B-cells. While T-cells attack cells infected by virus and cancer cells. B-cells produce and release antibodies or protein substances which destroy and remove infectious agents from the body.
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  3. How Does Hematopoietic Cell Transplantation (HCT) Work?
    First, we should start by answering the question: what is hematopoiesis? Hematopoiesis is the formation and development of blood cells. Cells used in transplantation come from three primary sources

    1. bone marrow
    2. umbilical cord blood
    3. mobilized Peripheral Blood Stem Cells (PBSC). They circulate in the blood stream in small numbers.

    The transplantation process works by: first destroying the patient's diseased or damaged bone marrow and, then, replacing it with healthy bone marrow, stem, or cord blood cells hoping that it will finally develop into a healthy and functioning cell system. PBSC transplantation is becoming more common for a variety of diseases.
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  4. Why Are Marrow Transplants Used?
    It is when the bone marrow's main function is disturbed and no longer produces the correct amount of the body's blood. Today, transplantation is considered a standard treatment approach for many immunologic, hematologic, malignant, and inherited diseases. For example, in leukemia, bone marrow excessively produces immature or defective blood cells. Another example is the low blood cell counts of aplastic anemia.
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  5. What Are the Eligibility Criteria for a Transplant?
    Not one criterion determines the eligibility of a patient for bone marrow transplantation (BMT). The criteria vary widely depending on many factors, such as disease, stage of disease, age, previous medical treatment, and current medical condition.
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  6. Who Determines When a Person Is Eligible?
    The attending physician will review each patient's case, including medical history, to determine the appropriate protocol or treatment plan suitable to treat the disease.
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  7. How Is the Healthy Marrow Replaced or Transplanted?
    Following chemotherapy, when the  patient's diseased bone marrow is destroyed, s/he is given the healthy bone marrow, which is infused into the patient's blood intravenously (like a blood transfusion) through a catheter implanted into a large vein in the chest. In a successful bone marrow transplantation (BMT), the new bone marrow travels to the cavities of the large bones and begins producing normal blood cells.

    BMT procedures are of three types: autologous, allogeneic, and syngeic.

    In the autologous transplantation, the bone marrow that is transplanted is the patient's own marrow. In fact, cells are extracted from the patient’s marrow in a process known as harvesting/collection. They are, then, either stored in a cryogenic freezer at a temperature of -180ºC waiting for transplantation or transplanted within 24 hours of collection.

    In the allogeneic transplantation, however, the bone marrow is that of a family member or unrelated donor. The ideal donor has a tissue type which matches the patient's tissue type as closely as possible. If such a donor is not available, it is possible that an unrelated donor may be identified. These donors come from the general population and are identified through marrow-donor registries.

    Syngeic transplantation uses the bone marrow from an identical twin.
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  8. How Are Transplants Performed?
    • Catheter
      Before the transplantation, a central, intravenous catheter (central line) is inserted into a large vein in the patient's chest, just above the heart. This line is used to administer chemotherapy, medication, nutritional supplements, and blood products to the patient.

    • Conditioning Regimen
      Before infusing healthy cells and in order to destroy cancer cells, patients undergo conditioning regimen of high-dose chemotherapy (with/or without radiation therapy). The marrow, which is a soft-tissue organ, will be destroyed by such a harsh treatment. For patients with marrow-involved diseases, such as leukemia, this is a primary goal, but this is not the case for patients with other diseases. This is why the conditioning regimens vary according to the patient's disease and medical condition.

    • Transplantation
      Harvested cells are infused through the catheter. They travel through the blood system and move into the bones where the immature cells grow into functioning cells. It will take several weeks for new cells to begin developing. During this time, the patient will have a highly-depressed immune system.
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  9. How Is the Bone Marrow Or the Hematopoeitic Stem Cells (HSC) Collected?
    It can be from the patient herself/himself (autologous) or a donor (allogeneic).

    1. From the Bone Marrow
      Collection takes place in an operating room, involves little risk and minimal discomfort, and is usually done under general anesthesia. The physician inserts a needle into the cavity of the hip bone where a large quantity of bone marrow is located. Several skin punctures on each hip and multiple bone punctures are usually required to extract the requisite amount of bone marrow. There are no surgical incisions or stitches involved, only skin punctures where the needle was inserted.

    2. From the Peripheral Stem Cells
      Stem cells are mobilized from the bone marrow into the peripheral blood circulation
      using daily administration of mobilizing agents, such as G-CSF (Granulocyte-Colony Stimulating Factors). Once the peripheral stem cells (PSC) in the circulating blood reach a certain level, the PSC are collected using a collection apparatus.
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  10. How Is the Collection Stored?
    There are two ways to store the marrow/ Hematopoeitic Stem Cells (HSC):

    1. Cryporeservation in liquid nitorgen at -180º C for a long-term storage (up to months/years)
    2. Freezing at -80º C for short-term storage

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  11. How Does It Feel After the Marrow Is Harvested?
    There may be some discomfort at the harvest site. The pain can usually be controlled with acetaminophen.
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  12. Once Harvested, When Does the Transplantation Occur?
    Transplantation can take place a week or two after treatment depending on the patient’s response to the treatment.
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  13. What Happens After the Transplantation?
    The first two to four weeks after transplantation are critical. The transplanted bone marrow/ Hematopoeitic Stem Cells (HSC) migrate to the cavities of the large bones and engraft (begin producing normal blood cells). The patient's defense mechanism will be very weak because of the high-dose of chemotherapy and/or radiation therapy prior to transplantation. The patient will be highly susceptible to infection and excessive bleeding (immunosuppressed). This is overcome by antibiotics and blood and platelets transfusion, when necessary. Patients who receive bone marrow cells from a donor (an allogeneic transplantation) are given medications to prevent and control graft-versus-host disease.
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  14. How Is the Patient Protected During This Time of Vulnerability?
    The patient remains hospitalized in single isolation room where outside visitors are limited, and only a parent may stay with the patient at all times. Visitors and hospital personnel wash their hands and wear masks while in the patient's room.
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  15. How Is the Transplantation's Success Evaluated?
    Blood samples are taken daily as a mean of monitoring organ function and to determine whether or not the engraftment has occurred. When the transplanted bone marrow finally engrafts and begins producing normal blood cells, the patient will gradually be taken off the antibiotics, and blood and platelet transfusions will be reduced and eventually will no longer be needed. When a sufficient number of healthy red blood cells (RBC's), white blood cells (WBC's), and platelets are produced, the patient will be discharged from the Medical Center. A patient receiving a bone marrow Transplantation (BMT) typically spends three to six weeks in the Medical Center.
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  16. What Is the Average Recovery Period for Transplantation Patients?
    The period of recovery depends on each patient. On average, the inpatient stay is between 21 and 35 days. Patients are, then, discharged to outpatient status. Post-transplantation patients are monitored closely in the physician's clinic. While on outpatient status, patients have regular blood draws to monitor cell counts, receive nutritional counseling, undergo physical exams, etc...  If complications occur, the patient is re-admitted immediately. During the recovery period, the patient's cells counts generally continue to develop. It may be a year to two years before the immune system is fully functioning. During this period, infection can cause serious problems for patients, sometimes death. All patients are encouraged to limit exposure to infectious diseases (especially staying away from crowds). This includes staying away from people with colds, flu viruses, or any other infectious disease.
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  17. What Is the Success Rate for Marrow Transplantation?
    The success rate for patients whether receiving a bone marrow, stem cell, or cord blood transplantation varies depending on a number of factors. This includes, but is not limited to: age, current medical condition, type and stage of disease, response to previous treatment and donor match.
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  18. Does the Absence of Disease Mean Cure?
    No. Unfortunately, so far, there has been no guarantee that the disease will not return (relapse/progress) after transplantation. The average recovery period ranges from one to two years after transplantation. Each year a person lives without major complications or relapse increases the possibility for long-term survival.
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  19. What Is HLA or Human Leukocyte Antigens?
    HLA are a series of protein molecules on the surface of all cells. Patient and potential donor are usually compared (i.e. their proteins on the cells are compared). This is what we call HLA typing. The HLA system comprises the following systems: HLA-A, B, C, DR, and DQ, and out of them, five major genes should match ideally for matching to be acceptable. Mismatching for one of these genes may be acceptable in certain situations. There are two antigens encoded by each gene. A full match for all five genes is scored as a 10-out-of-10 match, such as in the case of identical siblings. The only perfectly matched individuals are identical twins. There are other genes, besides the HLA system. However, they play a less important role in transplantation.
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  20. What Are the Techniques Used for Typing/Comparing Donors?
    Two techniques have been regularly used, so far, for typing donors:

    1. serologic testing that compares Human Leukocyte Antigens (HLA) proteins found on the cells
    2. DNA methods that analyze the differences in the genes that produce HLA proteins

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  21. What Are the Different Types of Bone Marrow Transplantation Performed at AUBMC?
    Currently, two types of transplantation are being performed at AUBMC: Autologous Peripheral Stem Cell Transplantation (APSCT) and allogeneic bone marrow transplantation (BMT) using Human Leukocyte Antigens (HLA) matched sibling donors. Near future projects are to perform allogeneic BMT using HLA-matched, unrelated donors.
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Bone Marrow Transplantation (BMT) Program American University of Beirut Medical Center Department of Internal Medicine