Page 1205 - Veterinary Immunology, 10th Edition

antibodies make the airways highly irritable, and affected
VetBooks.ir individuals develop severe asthma.

Type III Hypersensitivity

Autoantibodies form immune complexes with autoantigens, and

these complexes may cause inflammation. This is most significant
in systemic lupus erythematosus, a disease in which many different
autoantibodies are produced. Immune complexes deposited in

glomeruli provoke a membranoproliferative glomerulonephritis
(Chapter 32). Similarly, in rheumatoid arthritis, immune complexes
are deposited in joints and contribute to the local inflammatory
response.

Type IV Hypersensitivity

Many autoimmune disease lesions are infiltrated with mononuclear
cells, and T cells probably contribute to their pathogenesis.
Cytotoxic T cells cause demyelination in experimental allergic

encephalitis and multiple sclerosis. Insulin-dependent diabetes
mellitus may be due to a T cell–mediated response because the
diseased pancreatic islets may be infiltrated by lymphocytes.
Lymphocytes from diabetics may be cytotoxic for pancreatic islet

cells in vitro. Although cytotoxic T cells can kill cells directly,
cytokines may also cause tissue damage. For example, TNF-α
upregulates cell adhesion molecules, including selectins, facilitating
migration of neutrophils into the lesions.

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