Hypersensitivity reaction
Updates to Article Attributes
Body
was changed:
Hypersensitivity reactions are the immunological response to both exogenous and endogenous antigens, and forms the basis for many diseases.
Pathology
Classification
There are four types of hypersensitivity reactions, each mediated by a different mechanism 1-4:
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type 1 hypersensitivity: immediate reaction
- IgE mediated.
- Binds to Fc membrane receptor on mast cells and interacts with corresponding antigen.
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Mast cell degranulation occurs on following exposure (8)
- urticaria
- asthma
- allergy/anaphylaxis
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type 2 hypersensitivity: antibody mediated reaction
- IgG/ IgM mediated
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causesCauses cell destruction and disrupts cell function. (5)
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type 3 hypersensitivity: immune-complex mediated reaction
- IgG/IgM mediated
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antibodyAntibody-antigen Immunocomplex deposition -
These can activate complement, cause release of chemotactic and clotting factor and trigger phagocytosis.
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vasculitidesvasculitis (6) - systemic lupus erythematosus (SLE)
- hypersensitivity pneumonitis
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type 4 hypersensitivity: cell mediated reaction
- 'delayed' hypersensitivity
- T-helper cells secrete various different cytokines resulting in different immune reactions.
- interferon y secreted by T-helper type 1
- these cytokines activate macrophages.
- this leads to production of complement-fixing antibody isotypes stimulating inflammatory responses.
- CD8+ T-cell mediated killing of cells expressing reactive antigen in association with MHC-1.
- IL-4, IL-5,IL13 secreted by T-helper type 2
- stimulate B cell activation and production of immunoglobulins (IgE), mast cell and eosinophil reactions and macrophage deactivation.
- other T-cells contain granules performing cytoxic functions by the release of peforin/granzymes directly killing the infected cells.(7)
- contact dermatitis
- coeliac disease
- transplant rejection
- type 1 diabetes
- multiple sclerosis
- interferon y secreted by T-helper type 1
-<li>mast cell degranulation occurs on following exposure<ul>- +<li>Binds to Fc membrane receptor on mast cells and interacts with corresponding antigen.</li>
- +<li>Mast cell degranulation occurs on following exposure (8)<ul>
-<li>causes cell destruction and disrupts cell function.<ul>- +<li>Causes cell destruction and disrupts cell function. (5)<ul>
-<li>antibody-antigen Immunocomplex deposition<ul>-<li>vasculitides</li>- +<li>Antibody-antigen Immunocomplex deposition</li>
- +<li>These can activate complement, cause release of chemotactic and clotting factor and trigger phagocytosis.<ul>
- +<li>vasculitis (6)</li>
-<li>other T-cells contain granules performing cytoxic functions by the release of peforin/granzymes directly killing the infected cells.<ul>- +<li>other T-cells contain granules performing cytoxic functions by the release of peforin/granzymes directly killing the infected cells.(7)<ul>
References changed:
- 5. Pichler W. Delayed Drug Hypersensitivity Reactions. Ann Intern Med. 2003;139(8):683-93. <a href="https://doi.org/10.7326/0003-4819-139-8-200310210-00012">doi:10.7326/0003-4819-139-8-200310210-00012</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/14568857">Pubmed</a>
- 5. Pichler W. Delayed Drug Hypersensitivity Reactions. Ann Intern Med. 2003;139(8):683-93. <a href="https://doi.org/10.7326/0003-4819-139-8-200310210-00012">doi:10.7326/0003-4819-139-8-200310210-00012</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/14568857">Pubmed</a>
- 6. Powell C, Thompson L, Murtaugh R. Type III Hypersensitivity Reaction with Immune Complex Deposition in 2 Critically Ill Dogs Administered Human Serum Albumin. J Vet Emerg Crit Care (San Antonio). 2013;23(6):598-604. <a href="https://doi.org/10.1111/vec.12085">doi:10.1111/vec.12085</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23941553">Pubmed</a>
- 6. Powell C, Thompson L, Murtaugh R. Type III Hypersensitivity Reaction with Immune Complex Deposition in 2 Critically Ill Dogs Administered Human Serum Albumin. J Vet Emerg Crit Care (San Antonio). 2013;23(6):598-604. <a href="https://doi.org/10.1111/vec.12085">doi:10.1111/vec.12085</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23941553">Pubmed</a>
- 7. Posadas S & Pichler W. Delayed Drug Hypersensitivity Reactions - New Concepts. Clin Exp Allergy. 2007;37(7):989-99. <a href="https://doi.org/10.1111/j.1365-2222.2007.02742.x">doi:10.1111/j.1365-2222.2007.02742.x</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/17581192">Pubmed</a>
- 7. Posadas S & Pichler W. Delayed Drug Hypersensitivity Reactions - New Concepts. Clin Exp Allergy. 2007;37(7):989-99. <a href="https://doi.org/10.1111/j.1365-2222.2007.02742.x">doi:10.1111/j.1365-2222.2007.02742.x</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/17581192">Pubmed</a>
- 8. Vitte, J., Claver, J. & Blank, U. 2012, "Mast cell degranulation: Current information", REVUE FRANCAISE D ALLERGOLOGIE, vol. 52, no. 4, pp. 340-344.•
- 5.Pichler, WJ 2003, 'Delayed Drug Hypersensitivity Reactions', Annals Of Internal Medicine, 139, 8, p. 683, Academic Search Complete, EBSCOhost, viewed 15 April 2016.
- 6. Powell, C., Thompson, L. & Murtaugh, R.J. 2013, "Type III hypersensitivity reaction with immune complex deposition in 2 critically ill dogs administered human serum albumin", Journal of Veterinary Emergency and Critical Care, vol. 23, no. 6, pp. 598-604.
- 6.• Vitte, J., Claver, J. & Blank, U. 2012, "Mast cell degranulation: Current information", REVUE FRANCAISE D ALLERGOLOGIE, vol. 52, no. 4, pp. 340-344.
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