Type IV hypersensitivity

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Type IV hypersensitivity
Other namesdelayed-type hypersensitivity; DTH; cell-mediated hypersensitivity
SpecialtyImmunology Edit this on Wikidata

Type IV hypersensitivity, in the Gell and Coombs classification of allergic reactions, often called delayed-type hypersensitivity, is a type of hypersensitivity reaction that can take a day or more to develop.[1] Unlike the other types, it is not humoral (not antibody-mediated) but rather is a type of cell-mediated response. This response involves the interaction of T cells, monocytes, and macrophages.

This reaction is caused when

multinucleated giant cells
.

The overreaction of the helper T cells and overproduction of cytokines damage tissues, cause inflammation, and cell death. Type IV hypersensitivity can usually be resolved with topical corticosteroids and trigger avoidance.[1]

Forms

Disease Target antigen Effects
Allergic contact dermatitis[2] Environmental chemicals, like
nickel
), topical medication
skin rash, and blisters
Autoimmune myocarditis[2]
Myosin heavy chain
protein
Cardiomyopathy
Diabetes mellitus type 1[2]
Pancreatic beta cell proteins (possibly insulin, glutamate decarboxylase) Insulitis, beta cell destruction
Granulomas[3] Various, depending on underlying disease Walled-off lesion containing macrophages and other cells
Some
peripheral neuropathies
Schwann cell antigen Neuritis, paralysis
Hashimoto's thyroiditis[2] Thyroglobulin antigen
hard goiter
, follicular thymitis
Inflammatory bowel disease[2]
Enteric microbiota
and/or self antigens
Hyperactivation of T-cells, cytokine release, recruitment of macrophages and other immune cells, inflammation
Multiple sclerosis[2] Myelin antigens (e.g., myelin basic protein) Myelin destruction, inflammation
Rheumatoid arthritis[2] Possibly
citrullinated
self proteins
Chronic arthritis, inflammation, destruction of articular cartilage and bone
Tuberculin reaction (Mantoux test)[3] Tuberculin
Induration and erythema
around injection site indicates previous exposure

An example of a

TNF-α which recruits multiple monocytes to the site of infection. These cells differentiate into epithelioid cells which wall off the infected cells, but results in significant inflammation
and local damage.

Some other clinical examples:

See also

References

  1. ^
    PMID 22165815
    .
  2. ^ .
  3. ^ a b "Hypersensitivity reactions". microbiologybook.org. University of South Carolina School of Medicine - Microbiology and Immunology On-line. Retrieved 29 May 2016.
  4. S2CID 19523447
    . Retrieved 18 June 2017.
  5. . Retrieved 28 November 2021.
  6. ^ Walter Duane Hinshaw (26 June 2021). "eMedicine - Hypersensitivity Reactions, Delayed".

External links