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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
| Type II hypersensitivity | |
|---|---|
| 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
The activation of the complement system results in opsonization, the agglutination of red blood cells, cell lysis, and cell death.[2]
Type II hypersensitivity reactions are also known as antibody-mediated cytotoxic reactions.[3] These reactions usually take between 2 and 24 hours to develop.[2]
| 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 acute hemolytic transfusion reaction following transfusion of ABO incompatible blood.[5] 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.[6][7]
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.[8]
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.[9]
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.[10]
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
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 complement activation via the classical complement pathway Antibody-dependent cellular cytotoxicity or anti-receptor activity. The activation of the complement system results in opsonization, the agglutination of red blood cells, cell lysis, and cell death. Type II hypersensitivity reactions are also known as antibody-mediated cytotoxic reactions. These reactions usually take between 2 and 24 hours to develop.
Bullous pemphigoid (a type of pemphigoid) is an autoimmune pruritic skin disease that typically occurs in people aged over 60, that may involve the formation of blisters (bullae) in the space between the epidermal and dermal skin layers. It is classified as a type II hypersensitivity reaction, which involves the formation of anti-hemidesmosome antibodies, causing a loss of keratinocytes to basement membrane adhesion.
Pemphigus vulgaris is a rare chronic blistering skin disease and the most common form of pemphigus. Pemphigus was derived from the Greek word pemphix, meaning blister. It is classified as a type II hypersensitivity reaction in which antibodies are formed against desmosomes, components of the skin that function to keep certain layers of skin bound to each other. As desmosomes are attacked, the layers of skin separate, and the clinical picture resembles a blister. These blisters are due to acantholysis, or the breaking apart of intercellular connections through an autoantibody-mediated response. Over time the condition inevitably progresses without treatment: lesions increase in size and distribution throughout the body, behaving physiologically like a severe burn. Before the advent of modern treatments, mortality for the disease was close to 90%. Today, the mortality rate with treatment is in the range of 5–15%, after the introduction of corticosteroids as primary treatment. Nevertheless, in 1998, pemphigus vulgaris was the fourth most common cause of death due to a skin disorder. It is thus still deemed "potentially fatal". The disease mainly affects middle-aged and older adults between 50 and 60 years old. There has historically been a higher incidence in women.
Type I hypersensitivity (or immediate hypersensitivity), in the Gell and Coombs classification of allergic reactions, is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. Type I is distinct from type II, type III and type IV hypersensitivities. The relevance of the Gell and Coombs classification of allergic reactions has been questioned in the modern-day understanding of allergy, and it has limited utility in clinical practice. Exposure may be by ingestion, inhalation, injection, or direct contact.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Joe Louis.
