Type II hypersensitivity

Video explanation
Specialty| Immunology

Type II hypersensitivity, in the Gell and Coombs classification of allergic reactions, is an antibody mediated process in which IgG and IgM antibodies are directed against antigens on cells (such as circulating red blood cells) or extracellular material (such as basement membrane). This subsequently leads to cell lysis, tissue damage or loss of function through mechanisms such as

1. complement activation via the classical complement pathway
2. antibody dependent cell-mediated cytotoxicity  or
3. 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]

## Contents

* 1 Examples
* 2 See also
* 3 References
* 4 External links

## Examples[edit | edit source]

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

[3]

An example of complement dependent type II hypersensitivity is an acute haemolytic transfusion reaction following transfusion of 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.

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.[5]

An example of anti-receptor type II hypersensitivity (also classified as type V hypersensitivity) is observed in Graves disease, in which anti-thyroid stimulating hormone receptor antibodies lead to increased production of thyroxine.[6]

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.[7]

## See also[edit | edit source]

* Type I hypersensitivity
* Type III hypersensitivity
* Type IV hypersensitivity
* Type V hypersensitivity

## References[edit | edit source]

1. ↑ "Immunopathology". Archived from the original on 1 September 2017. Retrieved 17 March 2019.
2. ↑ 2.0 2.1 Warrington, Richard; Watson, Wade; Kim, Harold L.; Antonetti, Francesca Romana (10 November 2011). "An introduction to immunology and immunopathology". Allergy, Asthma, and Clinical Immunology. 7 (1): S1. doi:10.1186/1710-1492-7-S1-S1. ISSN 1710-1492. PMC 3245432. PMID 22165815.
3. ↑ "Hypersensitivity reactions". Amboss. Archived from the original on 20 April 2019. Retrieved 20 April 2019.
4. ↑ Tinegate, Hazel; Birchall, Janet; Gray, Alexandra; Haggas, Richard; Massey, Edwin; Norfolk, Derek; Pinchon, Deborah; Sewell, Carrock; Wells, Angus; Allard, Shubha (October 2012). "Guideline on the investigation and management of acute transfusion reactions Prepared by the BCSH Blood Transfusion Task Force". British Journal of Haematology. 159 (2): 143–153. doi:10.1111/bjh.12017. PMID 22928769.
5. ↑ Goodpasture Syndrome at eMedicine
6. ↑ Graves Disease at eMedicine
7. ↑ Descotes, Jacques; Choquet-Kastylevsky, Geneviève (February 2001). "Gell and Coombs's classification: is it still valid?". Toxicology. 158 (1–2): 43–49. doi:10.1016/S0300-483X(00)00400-5.

## External links[edit | edit source]

Classification|

* MeSH: D001327
* DiseasesDB: 33482

|

External resources|

* MedlinePlus: 000821

* v
* t
* e

Hypersensitivity and autoimmune diseases

Type I/allergy/atopy
(IgE)|

| Foreign|

* Atopic eczema
* Allergic urticaria
* Allergic rhinitis (Hay fever)
* Allergic asthma
* Anaphylaxis
* Food allergy
* common allergies include: Milk
* Egg
* Peanut
* Tree nut
* Seafood
* Soy
* Wheat
* Penicillin allergy

|

Autoimmune|

* Eosinophilic esophagitis

Type II/ADCC

*     * IgM
* IgG

| Foreign|

* Hemolytic disease of the newborn

|

Autoimmune|

| Cytotoxic|

* Autoimmune hemolytic anemia
* Immune thrombocytopenic purpura
* Bullous pemphigoid
* Pemphigus vulgaris
* Rheumatic fever
* Goodpasture syndrome
* Guillain–Barré syndrome

|

"Type V"/receptor|

* Graves' disease
* Myasthenia gravis
* Pernicious anemia

Type III
(Immune complex)|

| Foreign|

* Henoch–Schönlein purpura
* Hypersensitivity vasculitis
* Reactive arthritis
* Farmer's lung
* Post-streptococcal glomerulonephritis
* Serum sickness
* Arthus reaction

|

Autoimmune|

* Systemic lupus erythematosus
* Subacute bacterial endocarditis
* Rheumatoid arthritis

Type IV/cell-mediated
(T cells)|

| Foreign|

* Allergic contact dermatitis
* Mantoux test

|

Autoimmune|

* Diabetes mellitus type 1
* Hashimoto's thyroiditis
* Multiple sclerosis
* Coeliac disease
* Giant-cell arteritis
* Postorgasmic illness syndrome
* Reactive arthritis

GVHD|

* Transfusion-associated graft versus host disease

Unknown/
multiple|

| Foreign|

* Hypersensitivity pneumonitis
* Allergic bronchopulmonary aspergillosis
* Transplant rejection
* Latex allergy (I+IV)

|

Autoimmune|

* Sjögren syndrome
* Autoimmune hepatitis
* Autoimmune polyendocrine syndrome
* APS1
* APS2
* Autoimmune adrenalitis
* Systemic autoimmune disease

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