Immunodeficiencies

From Pig
Immunodeficiency Diagram - Copyright NA Brown RVC

Like any system in the body the porcine immune system can go wrong. Autoimmunity is when the immune system begins to attack itself. Immunodeficiency is when the immune system fails to protect itself from disease.

If the immunodeficient defect is present at birth and is therefore a result of a genetic or developmental abnormality, it is called a primary immunodeficiency.

Secondary immunodeficiency, sometimes called acquired immunodeficiency, is the loss of immune function during life, caused by exposure to harmful agents.

Immunodeficiencies can be treated by the replacement of the defective or missing protein, cells or gene. However, in veterinary medicine, vaccinations and drugs are the most common treatments for immunodeficiency.

Primary Immunodeficiency

  • Primary immunodeficiencies may affect either the innate immune system or the adaptive immune system
  • They are categorised by either the type or the developmental stage of the cells involved
  • Lymphoid cell disorders affect T cells or B cells (or both)
  • Myeloid cell disorders affect phagocytic function
  • The severity of the immunodeficiency depends on at which stage in development the problem occurs
    • E.g. Defects early on in development will affect the entire immune system
  • T cell deficiencies can affect both the cell-mediated and humoral response as T cells play a central role in the immune system

Secondary Immunodeficiency

  • There are many causes of secondary immunodeficiency
    • Most deficiencies are not genetic
    • Most are agent-induced, such as from X-ray radiation and immunosuppressive drugs
  • Viral Causes
  • Toxic Causes
  • Poisons
  • Iatrogenic Causes
  • Drugs

Other Causes

  • Malnutrition
  • Chronic disease
  • Stress
  • Senescence