Complement Associated Diseases

For a description of the system and its functions see Complement.

Most diseases associated with complement are linked to deficiencies of certain components.
Some deficiencies give inefficient removal of immune complexes, resulting in autoimmune disease.
- E.g. deficiencies in C1, C2, C4 and DAF.
- Immune complexes lodge ing the small capillary beds and induce inflammation.
  - Results in, for example, glomerulonephritis, vasculitis, rheumatoid arthritis and inflammation/ irritation of the skin.
- E.g. Systemic Lupus Erythematosis.
Deficiencies may also result in chronic infection.
- E.g. deficiences in C3, Factor B and Factors H and I.
  - Factors H and I are inhibitors.
    - Lack of thrse results in exhaustion of the C3 supply, causing a functional C3 deficiency.
- Opsonisation and the lytic pathway do not function optimally without C3.
Other deficiencies.
- C6
  - Results in very few effects other that the inability to eliminate encapsulated bacterial infections.
- C1 esterase inhibitor.
  - A rare genetic deficiency.
  - C1 esterase inhibitor is an enzyme which controls the functioning of C1 esterase.
  - Lack of this enzyme causes inappropriate activation of C2 and production of large quantities of C2a (also known as C2 kinin).
    - C2 kinin is a potent inducer of inflammation and of vasodilatation.
      - Results in hereditary angiodaema.