Type II hypersensitivity
| Type II hypersensitivity | |
|---|---|
| Specialty | Immunology |
Type II hypersensitivity, in the
cell lysis
, tissue damage or loss of function through mechanisms such as
- complement activation via the classical complement pathway
- Antibody-dependent cellular cytotoxicity or
- anti-receptor activity.[1]
The activation of the complement system results in
opsonization, the agglutination of red blood cells, cell lysis, and cell death.[2]
These reactions usually take between 2 and 24 hours to develop.[2]
Examples
| Disease | Autoantibody target |
|---|---|
| Autoimmune hemolytic anemia | Red blood cells |
| Goodpasture syndrome | Glomerular basement membrane |
Graves disease |
Thyroid stimulating hormone receptor |
Immune thrombocytopenia |
Platelets |
| Myasthenia gravis | Muscle acetylcholine receptor |
An example of complement dependent type II hypersensitivity is an
ABO incompatible blood.[4] Preformed antibody (predominantly IgM) against donor red cell antigens not found in an individual of a particular blood group (e.g. anti-A IgM in an individual with blood group B), bind to the donor red cell surface and lead to rapid complement mediated haemolysis and potentially life-threatening clinical consequences. Complement-dependent type II hypersensitivity can also occur during the transmission of incompatible maternal antibodies to fetal red blood cells causing hemolytic anemia in the fetus, known as erythroblastosis fetalis.[5][6]
Another example of a complement dependent type II hypersensitivity reaction is
Goodpasture's syndrome, where the basement membrane (containing collagen type IV) in the lung and kidney is attacked by one's own antibodies in a complement mediated fashion.[7]
An example of anti-receptor type II hypersensitivity (also classified as type V hypersensitivity) is observed in
thyroxine.[8]
However, there are questions as to the relevance of the Gell and Coombs classification of allergic reactions in modern-day understanding of allergy and it has limited utility in clinical practice.[9]
See also
References
- ^ "Immunopathology".
- ^ PMID 22165815.
- ^ "Hypersensitivity reactions". Amboss. Retrieved 20 April 2019.
- S2CID 9150295.
- ^ Betts, J. Gordon; Young, Kelly A.; Wise, James A.; et al. Anatomy and Physiology – via Openstax.org.
- ^ "Hemolytic Anemia". Johns Hopkins Medicine. 8 August 2021.
- ^ Goodpasture Syndrome at eMedicine
- ^ Graves Disease at eMedicine
- PMID 11164991.
External links