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Term applied to diseases to indicate that their cause is unknown.


Immature cells are cells which can divide to produce new cells but they have not yet developed a specialised function. Immature cells differentiate and develop specialised functions such as a red cell or platelet. Differentiated cells no longer have the ability to divide and make new cells.

Immature Reticulocyte Fraction (IRF)

A useful parameter for blood transfusion assessment in anaemia.

Immune Thrombocytopenic Purpura (ITP)

A common disorder characterised by a shortage of platelets. This can cause bruising and spontaneous bleeding. Anti-platelet antibodies can be found in the blood in some cases. It may take an acute or chronic form. (The acute form is more common in children or following an infection. The chronic form is more common in adults.)

Immune deficiency

This is when the body is less able to defend itself against infections by bacteria, viruses and fungi. It may be caused by leukaemia or a related disease or by treatment for such a condition.

 Immune response

The immune response is how your body recognizes and defends itself against bacteria, viruses, and substances that appear foreign and harmful like tissues of another individual as in the rejection of an organ transplant..

Immune system

The immune system is a network of cells, tissues and organs which defend the body against infection by bacteria, parasites, fungi or viruses. It can also detect and destroy cancer cells but this does not always work effectively.


Proteins in the blood plasma which act as antibodies and play an important part in controlling infections. For examples  IgG, IgM, IgA, IgD and IgE.


This is when the body’s immune system is weakened by treatment. Deliberate immunosuppression is a necessary part of a stem cell transplant.


This is a term used to describe conditions which progress slowly. Lymphoma of this kind is usually called indolent rather than chronic.


Infection is the invasion of a host organism’s body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to these organisms and the toxins they produce. Chronic Lymphocytic Leukaemia (CLL), patients are prediposed to infections because of immunodeficiency related to the leukaemia itself and as a results of cumulative immunosuppression related to CLL treatment.


Inflammation is a local defence response to injury or tissue damage. An inflamed area is hot, swollen, red and tender.

Intramuscular injection

Injection into a muscle.

Intravenous infusion

Delivering antibiotics, blood products, anti-cancer drugs or nutrients into a patient’s vein over a long period of time.

Intravenous injection

Delivering drugs into a vein through a syringe.

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