BONE MARROW TRANSPLANT

Bone Marrow transplant or Hematopoietic stem cell transplantation is a medical procedure performed to replace the bone marrow that has been damaged or destroyed by disease, hemotherapy or infection. This procedure involves transplanting blood stem cells, which travel to the bone marrow where they produce new blood cells and promote further growth of new marrow.

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CASE-Early September 2016, on a late evening, I received a call from the ER (Emergency Room) that a young 18-year-old boy’s family was seeking an emergency opinion from a haematologist for their son. He was found to have severe pancytopenia [severe reduction of all three cell lines –Hemoglobin (Hb), white blood cells (WBCs) and platelets] noted on a blood count (CBC) done for progressive fatigue over a month and new-onset rashes all over his body since a day.

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His evaluation revealed a related rare disorder of the bone marrow, called severe aplastic anaemia (SAA), that occurs due to near-complete dysfunction of the entire hematopoietic functioning(involving Hb, WBC and platelets). If left untreated, such patients rapidly deteriorate and die either due to the severe thrombocytopenia (low platelets) related massive bleeding, or severe opportunistic infections (fungal, bacterial or viral) due to their extreme low blood counts.

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In addition, these patients remain transfusion-dependent (requiring blood and platelet transfusions almost every two weeks) until any definitive therapy. Fortunately, none of that happened, and he lives today, healthy and upbeat as any young teenager would, though still under close supervision. He underwent a procedure called a bone marrow transplant (BMT), with his younger sibling brother being the stem cell donor. The patient experienced two episodes of near-fatal infections, along with several bleeding episodes due to his low platelets, before undergoing a transplant. His pre-transplant journey from severe and complete transfusion dependence and repeated vulnerability to infections, to a state of complete transfusion independence, post-transplant with now normal blood counts remains a miraculous ordeal lasting close to 4 months. The family was indeed fortunate enough to have their son back from the brink of death! Bone marrow transplants (BMT) are complicated procedures that involve replacing the entire hematopoietic(blood) system in an affected person through guided chemotherapy and subsequently, substituting it with a healthy donor hematopoietic stem cells (HSC). It is these donor HSCs, which eventually replenishes the patient’s hematopoietic system over time, and gives rise to all living blood cells like white blood cells (WBC), red blood cells(RBC) and platelets, giving a new lease of life to the patient and his/her family.

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Several disorders benefit from such procedures. In addition to the described case above of a classical patient with aplastic anaemia, BMTs are indicated in several other congenital bone marrow failure syndromes, hereditary diseases caused by faulty haemoglobin syntheses like thalassemia, sickle cell anaemias, immunodeficiency disorders with an impaired ability of their immune system to fight infections, life-threatening blood cancers like multiple myelomas, leukaemia and several other types of advanced tumours like lymphomas, neuroblastomas, etc. Approximately 1500 BMTs were recorded from 11 centres in a major publication from CMC Vellore, in Aug 2008. Since then, many more centres have been developed, and an estimated 8,000 more patients have undergone hematopoietic stem cell transplants (HSCT) in India. These are average numbers, as many centres do not participate in reporting and registering their transplant data.

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The reported success rate of transplants from India has been from 20% in uncontrolled blood cancers to 80% in young, fit patients with aplastic anaemia, who can be transplanted quickly before they develop serious infections or bleeding. These success rates have been comparable to the west, but in general, the success rate of the HSCT depends a lot on the indication of the transplant and a lot on the fitness of the patient. A factor that also plays a role is the optimum timing of the transplant. Long waiting queues at large centres in combination with lack of awareness about other centres offering such facilities often change the dynamics of a disease. In the last decade, several other institutions (including Mumbai) have come up offering such BMT services, with a high focus on quality and outcomes, but at a high cost to the family, more so due to the complexity of the process and its complications, and lack of adequate insurance cover. Hematopoietic stem cell transplant (HSCT) is called BMT, when the HSC are obtained from the bone marrow, peripheral blood stem cell transplant (PBSCT) when they are procured from the peripheral blood and cord blood transplant (CBT) when the umbilical cord blood is the source of the HSC.

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Autologous HSCT is done by collecting the patient’s own HSC, before giving them high dose chemotherapy, and then re-infusing these preserved HSC back to the patients after chemotherapy. In certain diseases, only stem cells from a normal healthy donor can be given to the patient to replace the damaged or the diseased bone marrow. This is called an allogeneic (donor other than the patient himself, i.e. either a sibling donor or an unrelated donor searched through stem cell registries)hematopoietic stem cell transplant (HSCT). The high costs of the transplants are often related to the high costs of the care and in general, a self-paying Indian with poor insurance cover. The process of allotransplants begins with identifying and appropriately staging the disease. The patient’s close relatives or even unrelated donors are tested for the compatibility of their human leukocyte antigens (HLAs).

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