What diseases might require a transplant from an unrelated donor?
Transplants of hematopoietic progenitors: an opportunity for more than just patients of leukaemia.
The transplant of hematopoietic progenitors (bone marrow, peripheral blood or umbilical cord blood) is, often, the only hope of a cure for many patients. The procedure consists of the replacement of damaged or destroyed bone marrow for the stem cells of a healthy person.
The bone marrow transplant is one of the selected treatments in many different leukaemia cases but leukaemia is not the only disease which can be cured through this process. With this document we want to inform you of the range of diseases that can be cured thanks to an allogeneic bone marrow transplant (using a donor, which could be a family member or a stranger). (1).
Searches initiated for a compatible donor by the Bone marrow Donor Registry for spanish patients, in 2010 (Image in Spanish).
Source: REDMO annual report 2010
*Leukaemias
The acute leukaemias (acute lymphoblastic leukaemia – ALL and acute myeloid leukaemia) make up the majority of cases for the Bone Marrow Donor's Registry (REDMO) in the search for non-related donors. For example, in 2010, both of these leukaemias made up more than 44% of the searches initiated by REDMO (2).
Leukaemia consists of the uncontrolled proliferation of an abnormal number of blood cells. These abnormal cells infiltrate the bone marrow, impeding the healthy cells and invading the blood and other organs.
Normally, the acute leukaemias are the most likely to require a bone marrow transplant. In many cases, the chronic leukaemias can be controlled with medication.
The leukaemias which are most likely to require the patient to undergo a hematopoietic transplant are: acute lymphoblastic leukaemia, acute myeloid leukaemia, acute post myelodysplastic leukaemia, acute secondary leukaemia, and chronic lymphocytic leukaemia.
*Lymphomas
The lymphomas are a group of neoplastic diseases (cancers) that develop in the lymphatic system, which forms part of the immune system of the human body. There are two main types of leukaemia: Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). It is not common for the patients of Hodgkin's lymphoma to undergo a transplant now that this disease can be controlled with chemotherapy treatment and/or and autologous bone marrow transplant. However, in cases where the aforementioned treatments are not enough a transplant from donor (family member or unrelated) could be used. In 2010, patients diagnosed with Hodgkin's lymphoma made up 6% of the searches started by REDMO. (2)
Microscopic view of the bone marrow cells in a patient suffering from Burkitt's lymphoma
In the non-Hodgkin's lymphomas, a certain type of lymphocyte is reproduced at an uncontrollable rate, with time causing the growth of the organ in which they are produced. Given that lymphatic tissue is found all around the body, the lymphomas can appear in any part of the organism and disseminate in the liver and other organs and tissues. There are many sub-types of non-Hodgkin's lymphoma and some require an allogeneic transplant of hematopoietic progenitors. The sub-types of non-Hodgkin's lymphoma which are most frequently treated through a transplant are: B, T, or NK cell lymphoma, follicular lymphoma, MALT lymphoma, lymphoplasmacytoid lymphoma, large cell diffused lymphoma, mantle cell lymphoma, Burkitt's lymphoma, anaplastic lymphoma, peripheral T-cell lymphoma, fungoid mycosis or Sézary syndrome and the hepatosplenic lymphoma.
*Myelodysplastic syndromes
In the myelodysplastic síndromes (MDS), the blood stem cells produced by the bone marrow and charged with the development of all the blood cells, do not mature properly and therefore, are not converted into healthy red blood cells, white blood cells or platelets.
In general, less severe cases of MDS do not require any treatment and remain stable for many years. The only definitive cure for MDS is a bone marrow transplant. However, the advanced age of many patients and the toxicity of the aforementioned procedure limit the use of this treatment to younger patients with a poor prognosis, who have a compatible donor available.
Patients with myelodysplastic syndromes most likely to need an allogeneic bone marrow transplant are: refractory anaemia with excess blasts, cytopenia refractory with multilineage dysplasia, chronic myelomonocytic leukaemia, and myelodysplastic syndromes with difficult classifications.
*Bone marrow aplasia
Bone marrow aplasia (BMA) is the disappearance of bone marrow stem cells charged with the production of all the blood cells. Patients with a less severe form of aplasia can be practically symptomless and not need any treatment. The method of treatment for more severe forms of bone marrow aplasia in younger patients is a bone marrow transplant.
*Congenital erythrocyturia abnormalities
The erythrocytes (also called red blood cells or haematids) are the most numerous elements in the blood. The haemoglobin is one of its main components, and its objective is to transport oxygen to the different tissues around the body. The congenital abnormalities of the erythrocytes which can cause the patient to undergo a bone marrow transplant in search of a cure are: Fanconi's anaemia, alpha thalassemia, beta thalassemia intermedia, drepanocytosis and sideroblastic anaemia.
*Alterations of the plasma cells
Alterations of the plasma cells or monoclonal gammapathies are a group of illnesses that include diverse haematological malignancies which are characterized by a disorder in the plasma cells and the immunoglobulins.
Malignant monoclonal gammapathies that can require a transplant of haematopoietic progenitors are: mulitiple myeloma, leukaemia of the plasma cells, Waldeström's macroglobulinemia, and amyloidosis.
*Congenital immunodeficiencies
Immunodeficiencies are a state in which the immune system does not fulfill its protective role which thus leaves the organism vulnerable to infections. Congenital immunodeficiencies manifest (apart from a few exceptions) from infancy and are due to defects which impede the correct functioning of the immune system.
There are different types of congenital immunodeficiencies but they are nonetheless extremely rare. Perhaps severe combined immunodeficiency (SCID) would be the most common of the diseases within this group. An allogeneic bone marrow transplant is the most effective form of treatment.
*Other disorders
We could list many more illnesses where a transplant of haematopoietic progenitors, is often the only opportunity for a cure. However, many of them are very rare diseases such as other neoplasias like primary myelofibrosis; histiocytosis, metabolic disorders and other non-neoplasm diseases.
(1) Evidentally this information is not provided as a replacement for a consultation with a specialist doctor. The haematologist of a patient is who decides which intervention is adequate in relation to the age of the patient, their physical condition and the level of the disease.
(2) Source: 2010 REDMO annual report
