Complement Associated Diseases

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

Complement Associated Diseases

• 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.