Allogeneic stem cell transplantation

Allogeneic stem cell transplantation refers to stem cells that are taken from a healthy donor and given to patients. This type of transplant is performed much less frequently in myeloma and is usually carried out in exceptional circumstances or within the context of a clinical trial.

The aim of an allogeneic transplant is to allow the donor stem cells to mature into functioning immune cells which have the ability to destroy any residual myeloma cells. This effect is known as ‘graft-versus-myeloma’ and if successful can produce a much longer remission than an autologous SCT.

There are, however, significant risks associated with this procedure. Specifically, the donor immune cells can attack the patient’s healthy cells, leading to ‘graft-versus-host disease’ (GVHD). This can be serious and potentially life-threatening.

To reduce the risk of GVHD, the donor’s cells must match the patient’s tissue type as closely as possible.  Therefore, the donor is usually related to the patient (e.g. a sibling). However, unrelated donors from volunteers or blood banks can be used if the tissue type matches. These are referred to as a matched unrelated donors (MUD).

Despite improvements in technique over the past two decades, allogeneic transplantation is still associated with significant mortality and morbidity. GVHD remains a common and serious complication of allogeneic SCT and can severely impact a person’s quality of life. It can affect any part of the patient but particularly the skin, lungs, liver and gastrointestinal tract. It can be prevented or treated in some cases with steroids or other immunosuppressive agents, but if severe, can result in organ failure or death.

It is difficult to predict who will respond best to allogeneic transplantation. The most important determining factor in deciding whether patients are suitable candidates is age.

The upper age limit at most accredited centres is 55-60 years of age, though careful consideration on a patient-by-patient basis is necessary irrespective of age.