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Immune system - general information

The human body's immune system is a complex network of cells and proteins that defends the body against infections. Disorders that result from abnormalities of the immune system include allergic diseases, immunodeficiencies and autoimmune disorders.

Research into the immune system has been active in recent decades. Australia and New Zealand have strong track records in these areas. This makes immunology and allergy a dynamic and constantly changing field of medicine.  Clinical immunology/allergy specialists translate this knowledge into clinical practice, by assessing and treating a range of common and rare diseases that involve the immune system.  These specialists are listed on the ASCIA website www.allergy.org.au/patients/locate-a-specialist

Overactivity of the immune system can take many forms, including allergic diseases, where the immune system makes an excessive response to proteins in substances (known as allergens) and autoimmune diseases, where the immune system mounts a response against normal components of the body.

  • Allergic diseases are extremely common.  These include food, drug or stinging insect allergy, anaphylaxis (life-threatening allergy), hay fever (allergic rhinitis), sinus disease, asthma, hives (urticaria), dermatitis and eczema.
  • Autoimmune diseases range from common to rare.  These include multiple sclerosis, autoimmune thyroid disease, type 1 diabetes, systemic lupus erythematosus, rheumatoid arthritis, systemic vasculitis.
  • Immunosuppression treatment is most often required for recipients of cancer chemotherapy and transplants (to prevent rejection or graft versus host disease). 

Underactivity of the immune system, also called immunodeficiency, can be inherited, acquired as a result of medical treatment or caused by another disease. Immunodeficiency predisposes people to infections and can be life threatening in severe cases.

  • Primary immunodeficiencies are conditions in which the immune system does not function correctly, leading to increased infections. These may be inherited, including X-linked Agammaglobulinaemia, X-linked Severe Combined Immunodeficiency, Complement deficiencies and Phagocyte cell deficiencies).
  • Acquired immunodeficiencies include HIV/AIDS.

Content updated January 2018

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