Leukotriene E
4 (LTE
4) is a
cysteinyl
Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine enables the formation of disulfide bonds, and often participates in enzymatic reactions as a nucleophile. Cysteine is c ...
leukotriene
Leukotrienes are a family of eicosanoid inflammation, inflammatory mediators produced in leukocytes by the redox, oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxyg ...
involved in
inflammation
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...
. It is known to be produced by several types of
white blood cell
White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...
s, including
eosinophils
Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along wi ...
,
mast cell
A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a p ...
s, tissue
macrophage
Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...
s, and
basophils
Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. They are the largest type of granulocyte. They are responsible for inflammatory reactio ...
, and recently was also found to be produced by
platelet
Platelets or thrombocytes () are a part of blood whose function (along with the coagulation#Coagulation factors, coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a thrombus, blood clot. Platelets have no ...
s adhering to
neutrophil
Neutrophils are a type of phagocytic white blood cell and part of innate immunity. More specifically, they form the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. Their functions vary in differe ...
s. It is formed from the sequential conversion of
LTC4 to
LTD4 and then to LTE
4, which is the final and most stable cysteinyl leukotriene. Compared to the short half lives of LTC
4 and LTD
4, LTE
4 is relatively stable and accumulates in breath condensation, in plasma, and in urine, making it the dominant cysteinyl leukotriene detected in biologic fluids. Therefore, measurements of LTE
4, especially in the urine, are commonly monitored in clinical research studies.
Increased production and excretion of LTE
4 has been linked to several respiratory diseases, and urinary LTE
4 levels are increased during severe asthma attacks and are especially high in people with
aspirin-exacerbated respiratory disease
Aspirin-exacerbated respiratory disease (AERD), also called NSAID-exacerbated respiratory disease (N-ERD) or historically aspirin-induced asthma and Samter's Triad, is a long-term disease defined by three simultaneous symptoms: asthma, chronic ...
.
Studies have suggested that LTE
4 works through its own distinct receptor, and although one has not yet been discovered, research is ongoing to isolate and characterize an LTE
4-specific receptor.
References
{{Leukotrienergics
Eicosanoids
Dicarboxylic acids