Fibrinoid necrosis is a specific pattern of
irreversible, uncontrolled cell death that occurs when
antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respon ...
-
antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of t ...
complexes are deposited in the walls of blood vessels along with
fibrin
Fibrin (also called Factor Ia) is a fibrous, non-globular protein involved in the clotting of blood. It is formed by the action of the protease thrombin on fibrinogen, which causes it to polymerize. The polymerized fibrin, together with pl ...
. It is common in the immune-mediated
vasculitides which are a result of
type III hypersensitivity
Type III hypersensitivity, in the Gell and Coombs classification of allergic reactions, occurs when there is accumulation of immune complexes (antigen-antibody complexes) that have not been adequately cleared by innate immune cells, giving rise ...
. When stained with
hematoxylin and eosin, they appear brightly
eosinophilic
Eosinophilic (Greek suffix -phil-, meaning ''loves eosin'') is the staining of tissues, cells, or organelles after they have been washed with eosin, a dye.
Eosin is an acidic dye for staining cell cytoplasm, collagen, and muscle fibers. ''E ...
and smudged.
Diseases
Fibrinoid necrosis is not limited to the immune-mediated vasculitides; many pathologic processes can lead to areas of fibrinoid necrosis. In
systemic lupus erythematosus
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Commo ...
, the
dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided ...
is often affected by
fluid accumulation and inflammation around the small vessels in the skin, which may show prominent fibrinoid necrosis. Also it's seen in rheumatoid nodules with similar pathology. Also seen in Serum Sickness(Type III hypersensitivity reaction)
References
{{pathology
Histopathology
Necrosis
Cellular processes