Eosinophil %

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Eosinophil granulocytes, usually called eosinophils or eosinophiles (or, less commonly, acidophils), are white blood cells that are one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. Along with mast cells, they also control mechanisms associated with allergy and asthma. They are granulocytes that develop during haematopoiesis in the bone marrow before migrating into blood.
These cells are eosinophilic or 'acid-loving' as shown by their affinity to coal and tar dyes: Normally transparent, it is this affinity that causes them to appear brick-red after staining with eosin, a red dye, using the Romanowsky method. The staining is concentrated in small granules within the cellular cytoplasm, which contain many chemical mediators, such as histamine and proteins such as eosinophil peroxidase, ribonuclease (RNase), deoxyribonucleases, lipase, plasminogen, and major basic protein. These mediators are released by a process called degranulation following activation of the eosinophil, and are toxic to both parasite and host tissues.
In normal individuals, eosinophils make up about 1-6% of white blood cells, and are about 12-17 micrometers in size.[1] They are found in the medulla and the junction between the cortex and medulla of the thymus, and, in the lower gastrointestinal tract, ovary, uterus, spleen, and lymph nodes, but not in the lung, skin, esophagus, or some other internal organs[vague] under normal conditions. The presence of eosinophils in these latter organs is associated with disorder. Eosinophils persist in the circulation for 8–12 hours, and can survive in tissue for an additional 8–12 days in the absence of stimulation.

An increase in eosinophils is called an eosinophilia, and is typically seen in people with a parasitic infestation of the intestines, a collagen vascular disorder (such as rheumatoid arthritis), malignant disorders such as Hodgkin's disorder, extensive skin disorders (such as exfoliative dermatitis), Addison's disorder, in the squamous epithelium of the esophagus in the case of reflux esophagitis, eosinophilic esophagitis, and with the use of certain drugs such as penicillin. In 1989, contaminated L-tryptophan supplements caused a deadly form of eosinophilia known as eosinophilia-myalgia syndrome, which was reminiscent of the Toxic Oil Syndrome in Spain in 1981.
Eosinophilia is usually associated with allergic disorders and infections from parasites such as worms. A high eosinophil count may be due to:
·Autoimmune disorders  
·Hay fever  
A lower-than-normal eosinophil count may be due to:
·Alcohol intoxication  
·Over production of certain steroids in the body (such as cortisol)  

Treatments used to combat autoimmune disorders and conditions caused by eosinophils include:
·corticosteroids- promote apoptosis. Numbers of eosinophils in blood are rapidly reduced  
·monoclonal antibody therapy- e.g., mepoluzimab or reslizumab against IL-5, prevents eosinophilopoiesis  
·antagonists of leukotriene synthesis or receptors  
·Gleevec (STI571)- inhibits PDGF-BB in hypereosinophilic leukemia  

Difference between percentage of eosinophils and absolute eosinophil count (AEC)
Absolute counts are extremely important. If eosinophil or other counts are reported as percentages of the total white blood count (wbc), the absolute values can be calculated as follows: Total wbc x % cell type reported / 100. This formula can be used for calculating the absolute eosinophil count, absolute neutrophil count, etc.

All information on this page is intended for your general knowledge only and does not provide medical advice, diagnosis or treatment.