Hypersensitivity

For other uses, see Hypersensitivity (disambiguation).
Hypersensitivity
Types of hypersensitivity reactions
SpecialtyImmunology

Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen.[1][2] It is an abnormality in the immune system that causes immune diseases including allergies and autoimmunity. It is caused by many types of particles and substances from the external environment or from within the body that are recognized by the immune cells as antigens.[3] The immune reactions are usually referred to as an over-reaction of the immune system and they are often damaging and uncomfortable.[4]

In 1963, Philip George Houthem Gell and Robin Coombs introduced a systematic classification of the different types of hypersensitivity based on the types of antigens and immune responses involved.[5] According to this system, known as the Gell and Coombs classification[6] or Gell-Coombs's classification,[7] there are four types of hypersensitivity, namely: type I, which is an Immunoglobulin E (IgE) mediated immediate reaction; type II, an antibody-mediated reaction mainly involving IgG or IgM; type III, an immune complex-mediated reaction involving IgG, complement system and phagocytes; and type IV, a cytotoxic, cell-mediated, delayed hypersensitivity reaction involving T cells.[8]

The first three types are considered immediate hypersensitivity reactions because they occur within 24 hours. The fourth type is considered a delayed hypersensitivity reaction because it usually occurs more than 12 hours after exposure to the allergen, with a maximal reaction time between 48 and 72 hours.[9] Hypersensitivity is a common occurrence: it is estimated that about 15% of humans have at least one type during their lives, and has increased since the latter half of the 20th century.[10]

  1. ^ Andreozzi, Laura; Giannetti, Arianna; Cipriani, Francesca; Caffarelli, Carlo; Mastrorilli, Carla; Ricci, Giampaolo (2019). "Hypersensitivity reactions to food and drug additives: problem or myth?". Acta Bio-Medica. 90 (3–S): 80–90. doi:10.23750/abm.v90i3-S.8168. ISSN 2531-6745. PMC 6502174. PMID 30830065.
  2. ^ Gargano, Domenico; Appanna, Ramapraba; Santonicola, Antonella; De Bartolomeis, Fabio; Stellato, Cristiana; Cianferoni, Antonella; Casolaro, Vincenzo; Iovino, Paola (2021). "Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns". Nutrients. 13 (5): 1638. doi:10.3390/nu13051638. ISSN 2072-6643. PMC 8152468. PMID 34068047.
  3. ^ Dispenza, Melanie C. (2019). "Classification of hypersensitivity reactions" (PDF). Allergy and Asthma Proceedings. 40 (6): 470–473. doi:10.2500/aap.2019.40.4274. ISSN 1539-6304. PMID 31690397. S2CID 207891282.
  4. ^ Tian, Bao-Ping; Zhou, Hong-Bin; Xia, Li-Xia; Shen, Hua-Hao; Ying, Songmin (2014). "Balance of apoptotic cell death and survival in allergic diseases". Microbes and Infection. 16 (10): 811–821. doi:10.1016/j.micinf.2014.07.004. ISSN 1769-714X. PMID 25111826.
  5. ^ Silverstein, Arthur M. "Philip George Houthem Gell. 20 October 1914 – 3 May 2001 Elected FRS 1969". Biographical Memoirs of Fellows of the Royal Society. 49: 163–178. doi:10.1098/rsbm.2003.0010. ISSN 0080-4606.
  6. ^ Descotes, J.; Choquet-Kastylevsky, G. (2001-02-02). "Gell and Coombs's classification: is it still valid?". Toxicology. 158 (1–2): 43–49. doi:10.1016/s0300-483x(00)00400-5. ISSN 0300-483X. PMID 11164991.
  7. ^ Rajan, T. V. (2003). "The Gell-Coombs classification of hypersensitivity reactions: a re-interpretation". Trends in Immunology. 24 (7): 376–379. doi:10.1016/s1471-4906(03)00142-x. ISSN 1471-4906. PMID 12860528.
  8. ^ Usman, Norina; Annamaraju, Pavan (2021), "Type III Hypersensitivity Reaction", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32644548, retrieved 2021-07-05  This article incorporates text available under the CC BY 4.0 license.
  9. ^ Marwa, Khaled; Kondamudi, Noah P. (2021), "Type IV Hypersensitivity Reaction", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32965899, retrieved 2021-07-05  This article incorporates text available under the CC BY 4.0 license.
  10. ^ Cite error: The named reference :4 was invoked but never defined (see the help page).