Healthy marrow
Densely cellular, dominated by maturing red cells with a normal scattering of white cells and platelets. Production is continuous and balanced.
Treatment process
What a bone marrow transplant involves, step by step
From the first marrow biopsy to the flight home: what is actually done, in what order, how long each stage takes and what it feels like for the patient.
Figure 1. Sites of active red marrow in an adult. Yellow, fatty marrow replaces red marrow in the limbs with age; the axial skeleton continues producing blood throughout life.
The procedure
What a bone marrow transplant is
Bone marrow is the tissue inside your bones where blood is manufactured. Every red cell, white cell and platelet in circulation began there, as a single haematopoietic stem cell.
In an adult, active blood-forming marrow is no longer spread through the whole skeleton. It is concentrated in the pelvis, sternum, ribs, vertebrae, skull and the upper ends of the femur — which is why a marrow harvest is taken from the pelvis, and why these are the sites a haematologist images and biopsies.
Marrow fails in one of three ways, and each has its own transplant logic:
- It produces the wrong cells. In leukaemia, abnormal white cells multiply and crowd out normal production.
- It produces faulty cells. In thalassaemia major and sickle cell disease, an inherited gene fault means the red cells made do not work.
- It stops producing. In aplastic anaemia the marrow becomes empty and counts fall across all three lineages.
A transplant addresses all three by replacing the stem cell population itself. In inherited disorders the new stem cells carry normal genes, which is why a successful transplant is curative rather than suppressive.
One cell, three jobs
Why replacing stem cells works
A haematopoietic stem cell is capable of becoming any blood cell the body requires, and of renewing itself indefinitely.
Figure 2. Haematopoiesis. A single self-renewing stem cell gives rise, through progenitor stages, to every cell in the blood. Replacing the stem cell population therefore replaces the entire blood and immune system.
That single property is what makes transplantation possible. Doctors are not replacing blood — transfused blood lasts weeks. They are replacing the factory. Once donor stem cells settle into the marrow cavities and begin dividing, the patient produces their own healthy blood for the rest of their life.
In an allogeneic transplant the donor's immune system comes with the graft. That brings a therapeutic benefit in blood cancers — donor lymphocytes recognise and destroy residual malignant cells, the graft-versus-tumour effect — and the corresponding risk of graft-versus-host disease, in which those same cells attack the recipient's skin, gut or liver.
Balancing those two is most of what a transplant physician does in the first hundred days.
Under the microscope
Healthy marrow, and two ways it fails
The same aspirate, magnified. Between them these three fields account for most of the diagnoses referred for transplantation.
Leukaemia
Immature white cells — blasts — proliferate without control and displace normal haematopoiesis, so functional blood cannot be produced.
Aplastic anaemia
The converse failure. The marrow is hypocellular and produces too few cells of every lineage, so counts fall across the board.
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Indications
Conditions treated with a transplant
Transplantation is used both to cure inherited disorders outright and to consolidate remission in malignant disease.
Blood cancers
- Acute myeloid leukaemia (AML)
- Acute lymphoblastic leukaemia (ALL)
- Chronic myeloid leukaemia (CML)
- Hodgkin & non-Hodgkin lymphoma
- Multiple myeloma
- Myelodysplastic syndromes
Inherited blood disorders
- Thalassaemia major
- Sickle cell disease
- Fanconi anaemia
- Diamond–Blackfan anaemia
Marrow failure
- Severe aplastic anaemia
- Pure red cell aplasia
- Paroxysmal nocturnal haemoglobinuria
Immune & metabolic
- Severe combined immunodeficiency
- Wiskott–Aldrich syndrome
- Hurler syndrome
- Adrenoleukodystrophy
Whether a transplant is appropriate depends on the diagnosis, disease status, organ function, age and donor availability. Only the treating transplant physician can confirm suitability.
Procedure
What happens, in order
Five stages. Select any stage to view it, or let the sequence run.
Stage 1 of 5 — the presenting problem.
Patient pathway
The ninety days
Most international patients spend around three months in India, of which roughly three weeks are spent as an inpatient.
Before travel · 1–3 weeks
Reports are reviewed and an opinion issued, normally within 48 hours. The hospital then provides a written estimate and a visa invitation letter for the patient and attendants.
Work-up · 7–10 days
Cardiac, pulmonary, hepatic and renal assessment; infection screening; dental review; confirmatory HLA typing; donor clearance; insertion of a central venous catheter.
Conditioning · 5–8 days
High-dose chemotherapy with or without irradiation. Donor cells are collected during this window, usually on the day before or the day of infusion.
Day 0
Infusion through the central line over one to two hours. The patient is awake; there is no operation.
Engraftment · 2–4 weeks
Counts fall to near zero, then recover as the graft takes. Transfusions, prophylactic antimicrobials and strict isolation throughout.
Outpatient · 6–8 weeks
Residence near the hospital with review two to three times weekly, tapering to weekly, until the team confirms fitness to fly — usually around day 90.
Attendants
Plan for at least one full-time attendant across the whole stay; two is better, as the isolation period is exhausting for a single carer. Medical attendant visas are commonly granted to two family members.
After you fly home
Immunosuppressants and prophylaxis continue for months — confirm availability in your country before departure. A full revaccination schedule normally begins six to twelve months post-transplant.
Outcomes
How to read a success rate
There is no single success rate for bone marrow transplantation, and any figure presented as one is misleading.
Outcome depends on the diagnosis, the disease status at transplant, the degree of HLA match, the patient's age and organ reserve, and the centre's experience with that specific indication. As a general pattern, transplant teams will tell you that:
- Children transplanted for thalassaemia major with a matched sibling donor, before significant iron overload, have among the best outcomes of any indication.
- Severe aplastic anaemia in young patients with a matched sibling donor also carries a high probability of long-term cure.
- Acute leukaemia transplanted in first remission does considerably better than the same disease transplanted after relapse.
- Autologous transplant for myeloma extends remission rather than curing the disease, and is normally followed by maintenance therapy.
Ask for your figure, not the average
Ask the transplant physician what outcome is expected for your specific diagnosis, stage, age and donor type, at that unit. A good team will give a range and explain its assumptions. A published average tells you very little about your own case.
Ready to start?
Most patients are admitted within three to four weeks of first contact.