A cluster of interlocking antigens and antibodies.
A substance formed when antibodies attach to antigens to destroy them. These complexes circulate in the blood and may eventually attach to the walls of blood vessels, producing a local inflammatory response. Immune complexes form in type III hypersensitivity reactions and are involved in the development of glomerulonephritis, serum sickness, arthritis, and vasculitis, which may be called immune-complex diseases.
Immune complexes are formed when an antigen, a foreign substance triggering the immune response, binds with an antibody produced by the immune system. Typically, the liver and spleen remove these complexes from the circulation. However, in certain cases, they may persist in the bloodstream and get deposited in organs or tissues, leading to inflammation, tissue damage, and specific immune complex diseases, also known as type III hypersensitivity reactions.
Extrinsic allergic alveolitis, also known as farmer’s lung, is an example of an immune complex disease. In this condition, immune complexes are formed in response to exposure to allergens like fungal spores. These complexes accumulate in the lungs, leading to inflammation of the tiny air sacs called alveoli. Other conditions resulting from immune complexes include certain types of glomerulonephritis, which is inflammation of the kidney’s tiny filtering structures. Additionally, immune complexes play a role in some connective tissue diseases like systemic lupus erythematosus and rheumatoid arthritis, as well as adverse reactions to streptokinase, a thrombolytic drug used in myocardial infarction (heart attack) treatment.