What Is a Bone Marrow Transplant?

Autologous versus allogeneic

In an autologous transplant, the patient's own stem cells are collected in advance and returned after high-dose chemotherapy — standard practice in multiple myeloma and some relapsed lymphomas. In an allogeneic transplant, cells come from a matched donor, which adds an immune attack against residual leukaemia but also the risk of graft-versus-host disease.

Donor matching

Donors are matched by HLA typing. A fully matched sibling is ideal, with roughly a one-in-four chance for any given brother or sister. Where no sibling matches, a haploidentical family donor — usually a parent or child — or an unrelated registry donor may be used, with modified protocols.

The stages of transplant

• Eligibility assessment — disease status, organ function, infection screening, dental review
• Stem cell collection from the patient or donor
• Conditioning chemotherapy over several days
• Stem cell infusion — the transplant itself, on 'day zero'
• Engraftment over roughly two to four weeks, with counts at their lowest
• Discharge and prolonged follow-up with infection prophylaxis

Risks stated plainly

Transplant carries serious risks: severe infection during the low-count period, bleeding, mucositis, organ toxicity, graft-versus-host disease in allogeneic transplants and, in a minority of patients, transplant-related mortality. These are quantified for the individual before consent, and weighed against the benefit expected in that specific disease.

Recovery and life afterwards

Blood counts usually recover within a month, but immune recovery takes six months to a year. During that time patients follow food and crowd precautions, take preventive medicines, and are revaccinated on a schedule. Most patients gradually return to work and normal activity, with continued follow-up.

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