GLOSSARY OF TERMS
Glossary
Here you will find definitions and meanings of some of the most frequently used terms on the site.
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The ANC refers to the number of neutrophils (a type of white cell) that a person has in their blood to fight infection. It is calculated by multiplying the total number of white cells by the percentage of neutrophils.
An Alkylating agent is a type of chemotherapy used to kill cancer cells by interfering with cancer cell division. Alkylating agents cause side effects because they also interfere with cell division in certain healthy tissues where cell division is frequent, such as the gastrointestinal tract. Cyclophosphamide is one of several types of alkylating agents.
ASCT is a treatment that uses donor stem cells to restore a patient’s marrow and blood cells. First, the patient is given conditioning therapy (high-dose chemotherapy or high-dose chemotherapy with total body radiation) to treat the blood cancer and to “turn off” the patient’s immune system so that the donor stem cells will not be rejected.
A type of transplant called a “reduced-intensity” or “non-myeloablative” transplant is sometimes used also; the “reduced intensity” transplant uses lower doses of conditioning therapy and may be safer, especially for older patients.
Anaemia is the result of a decrease in the number of red blood cells and, therefore, the haemoglobin concentration of the blood. The decrease in the haemoglobin level in the blood means that the blood is less able to carry oxygen. In severe cases, anaemia can cause a pale complexion, weakness, fatigue and shortness of breath on exertion.
Anthracyclines are chemotherapy agents that interact directly with the DNA in the nucleus of cells, thus interfering with cell survival.
Antibodies are proteins released by plasma cells (derived from B lymphocytes) that recognize and bind to specific foreign substances, called “antigens.” Antibodies coat, mark for destruction or inactivate foreign particles such as bacteria, viruses and harmful toxins found in the body.
Antibodies can also be made in the laboratory in two ways. The first way takes advantage of the fact that if material is injected from one species into a different species, the latter will recognize it as foreign and make antibodies to attack it. These antibodies are usually polyclonal antibodies; that is, they react to multiple targets (antigens).
The second way involves monoclonal antibodies, which react to only one target (antigen) and can be used in several important ways. They can be used to identify and classify types of blood cancers or be altered so as to become useful in antibody-mediated immunotherapy.
An antigen is a foreign substance, usually a protein, that stimulates an immune response when it is ingested, inhaled or comes into contact with the skin or mucous membranes. Examples of antigens are bacteria, viruses or allergens. Antigens stimulate plasma cells to produce antibodies.
Antimetabolites are chemotherapy agents that are generally similar to natural building blocks of DNA, RNA or some vitamins. However, they are changed from the natural chemical. When they substitute for the DNA or RNA building blocks within a leukaemic cell, the cell is unable to form normal DNA or RNA. This prevents the cell from growing.
Apheresis is the process of removing components of a donor’s blood and returning the unneeded parts to the donor. The process, also called “haemapheresis,” circulates blood from a donor through a filter-type apparatus, and then back to the donor. Apheresis makes it possible to remove desired elements from large volumes of blood. Platelets, red cells, white cells and plasma can be removed separately.
For example, this technique permits the harvest of enough platelets for transfusion from one donor (rather than six to eight separate donors). In this way, the recipient of the platelets is exposed to fewer donors or can be given HLA-matched platelets from a single related donor. This technique is also used to remove circulating blood stem cells, which can be frozen and stored for later use in transplantation.
This is a technique used to delay the progression of certain blood cancers. The autologous transplantation process takes place after the patient achieves a complete response (remission), or a good partial response, to induction drug therapy.
The process is as follows:
- the patient’s stem cells are harvested, usually from the blood;
- the stem cells are frozen for later use and the patient receives conditioning drug therapy;
- the stem cells are thawed and infused back to the patient through an indwelling catheter (central line).
Patients receive supportive care to help prevent and/or manage the side effects. Generally, after 10 to 14 days, blood counts begin to normalize and the side effects of the conditioning therapy begin to resolve.