Pr of. Dr Shahina Y asm in
,
, Type III Immune complex hypersensitivity
• IgG mediated - Immune complexes are removed from
circulation by reticulo-endothelial system.
• In persistent viral & bacterial infections, immune
complexes persist, deposit in tissues - complement
activation - induce an inflammatory response, mediators
increase vascular permeability, attract neutrophils, intra-
vascular clumping of platelets leading to vascular
occlusion, cause tissue damage and necrosis.
• Autoimmune diseases, antibodies produced against self
antigens, intermediate and small size antigen-antibody
complexes deposited in tissues like kidneys (nephritis),
joints (arthritis), blood vessels (vasculitis)
• Exam ples: Arthus reaction, Serum sickness