All our key terms explained

Below is a glossary of some of the key terms we use when talking about our work.

For more information about any of the information below, get in touch with our press office on or 0207 424 1300 (Out of hours: 07881 265 285)

An alternative form of a gene (one member of a pair) that’s located at a specific position on a specific chromosome and determines a distinct trait that can be passed on from parents to children.

A transplant using cells taken from a healthy donor and given to a patient. Sometimes called a graft.

A transplant using the patient’s own cells. Doctors collect their stem cells, remove their diseased cells, then return the stem cells to the patient.

Autologous transplant
A transplant using the patient’s own ’cleaned up’ stem cells.

British Bone Marrow Registry (the NHS’s bone marrow register).

Blood cancers
A term for cancers that affect the blood, bone marrow and lymphatic system. There are three main kinds of blood cancer – leukaemia, lymphoma and myeloma.

Bone marrow
Found in the centre of all large bones. Blood stem cells are produced there.

Bone marrow donation
The process of taking the bone marrow or peripheral blood stem cells from the donor. Doctors can do this in two ways: via bone marrow harvest or peripheral blood stem cell collection.

British Society of Blood and Marrow Transplantation.

Confirmatory testing
If a potential donor comes up as a match on our system for someone in need of a transplant, a confirmatory blood test helps establish if he/she is the best available match.

Cord blood
The blood in a pregnant woman’s umbilical cord and placenta. Cord blood is rich in stem cells, which can be used for lifesaving transplants. Anthony Nolan’s cord blood programme collects this blood after the safe delivery of babies.

The acceptance of a donor’s healthy blood stem cells when they’re infused into the patient’s bloodstream. If they’re engrafted, the donor’s blood stem cells then begin to produce normal blood cells.

People who donate their stem cells via peripheral blood stem cell (PBSC) collection receive injections of granulocyte-colony stimulating factor (G-CSF) before their donation. This increases the amount of blood stem cells they produce, and encourages the cells to move from their bone marrow to their circulating blood.

The Graft Identification Advisory Service. A service that Anthony Nolan offers to UK transplant centres to ensure that each patient gets the best possible donor.

Another name for the bone marrow or peripheral blood stem cells taken from the donor and given to the patient.

Graft-versus-host disease (GvHD). A patient’s immune system normally identifies ‘foreign’ cells in their body, such as bacteria or viruses, and attacks them, helping to protect against infection.

Sometimes, following a transplant, the patient’s new immune system recognises the patient’s old cells as different. If this happens, the donor’s new white cells will attack the patient (its host).

Haematopoietic stem cells
These stem cells are found in the bone marrow. They produce red blood cells, white blood cells and platelets.

Haplo-identical stem cells
Stem cells taken from a donor, usually a sibling, which are not a perfect match for the recipient. Doctors may try to use these for a transplant if there is no better option.

Human leukocyte antigen (HLA) is the name for the molecules that have to match between a donor and a patient to make a transplant successful.

A cancer of the white blood cells. The four main types of leukaemia are:

  • Acute lymphoblastic leukaemia (ALL): a cancer of lymphocyte cells called lymphoblasts.
  • Acute myeloid leukaemia (AML): a cancer of the immature myeloid cells. It occurs mainly in adults but can also affect children.
  • Chronic lymphocytic leukaemia (CLL): a cancer of the lymphocyte cells. The most common type of leukaemia affecting adults. It’s very rare in children.
  • Chronic myeloid leukaemia (CML): a cancer of the neutrophils cells. This is also rare in children.

A type of white blood cell. After a blood stem cell transplant, a patient may need an infusion of lymphocytes from their donor.

Cancer of the white blood cells, localised in the lymph nodes.

When a patient and donor have the same tissue (HLA) types.

When a patient and donor have different tissue (HLA) types.

NHS Blood and Transplant, the Special Health Authority responsible for optimising the supply of blood, organs and tissues, including bone marrow. 

Peripheral blood stem cells
The blood stem cells that circulate in the body. Often abbreviated to PBSC.

An observable characteristic or trait of an organism such as its form, structure or behaviour. Phenotypes come from an organism’s genes, environmental factors – and the interaction between the two.

Stem cell
Stem cells have the potential to turn into any type of cell, regenerating dying cells and repairing any damaged by disease.

T cells (T lymphocytes)
A type of white blood cell that fights diseases, including tumour cells.

T reg cells (T regulatory cells)
A type of T cell that can control or regulate the body’s immune system. T reg cells can potentially control the development of graft versus host disease (GVHD), infection and/or disease relapse in bone marrow transplant patients.

Tissue type test
A test to see what type of tissue someone has, measuring substances called antigens on the surface of the body’s cells and tissues.

Transplant centres
The hospitals where donors donate their stem cells and patients receive them. For confidentiality and anonymity, the patient and their donor are always treated in separate transplant centres.

Unrelated donor
A donor who is not related to the patient. Approximately 70% of patients in the UK who receive a stem cell transplant get it from an unrelated donor.

White blood cell
The type of blood cell responsible for fighting infection.

Wiskott-Aldrich syndrome
The condition Anthony Nolan had. It’s an inherited immune system disorder, with symptoms including a low level of blood platelets, eczema, recurrent infections and a high risk of leukaemia and lymph node tumours.