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Research About EGID

What is an Eosinophil?
The eosinophil is a specialized cell of the immune system. This pro-inflammatory white blood cell generally has a nucleus with two lobes (bilobed) and cytoplasm filled with approximately 200 large granules containing enzymes and proteins with different (known and unknown) functions.
Eosinophils are formed exclusively in the bone marrow, where they spend about 8 days in the process of maturation before moving into the blood vessels. They travel through the vessels for 8 to 12 hours before they finally arrive at destination tissues, where they remain for 1 to 2 weeks. Interleukin 5 (IL-5) appears to be the major growth factor for this type of cell.

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The functions of the eosinophil are varied, some of which are very similar to other white blood cells. They are implicated in numerous inflammatory processes, especially allergic disorders. In addition, eosinophils may have a physiological role in organ formation (e. g. postgestational mammary gland development).

Eosinophilic functions include moving to inflamed areas, trapping substances, killing cells, antiparasitic and bactericidal activity, participating in immediate allergic reactions, and modulating inflammatory responses.

Eosinophils can be either helpful or harmful. At one extreme, such as in the illness erythema toxicum, eosinophils play the role of a beneficial modulatory element or an innocent bystander. At the other extreme, represented by conditions like Loeffler’s disease and idiopathic hypereosinophilic syndrome, eosinophils are linked with permanent pathologic changes.

Source: Cincinnati Center for Eosinophilic DisordersCincinnati Children’s Hospital Medical Center

What is an Eosinophilic Disorder?

Eosinophils are a normal cellular component of the blood and also of certain tissues, including spleen, lymph nodes, thymus, and the submucosal areas of the gastrointestinal, respiratory, and genitourinary tracts. Counts of 0 to 450 eosinophils per cubic millimeter of blood are considered within normal limits. Eosinophilic disorders occur when eosinophils are found in above-normal amounts in various parts of the body.

When the body wants to attack a substance, such as an allergy-triggering food or airborne allergen, eosinophils respond by moving into the area and releasing a variety of toxins. However, when the body produces too many eosinophils, they can cause chronic inflammation resulting in tissue damage. Eosinophilic disorders are diagnosed according to the location where the levels of eosinophils are elevated:

  • Eosinophilic esophagitis (esophagus)

  • Eosinophilic gastritis (stomach)

  • Eosinophilic enteritis (small intestine)

  • Eosinophilic colitis (large intestine)

  • Hypereosinophilic syndrome (blood and any organ)

There are many disorders where eosinophils have been found elevated in the blood or different tissues. General categories of disease, each with examples of those that have increased levels of eosinophils, range from allergic disorders to endocrine disorders.

Range of Disorders

Allergic Disorders

Allergic disorders are classically characterized by the presence of eosinophils. Allergic rhinoconjunctivitis (hay fever) has increased levels of eosinophils in the nasal mucosa. Asthma, after an exacerbation, shows increased numbers of eosinophils in the lung.

Drug Reactions

Any drug/medicine has the potential to cause a reaction. Some of these reactions are allergic in nature, and eosinophils might be elevated in blood or in tissues where the drug is concentrated.

Infectious Diseases

Parasitic infections (helminthiasis − worms), fungal infections, and some other types of infections are associated with increased numbers of eosinophils.

Blood Disorders

Hematologic disorders with increased levels of eosinophils include hypereosinophilic syndrome, leukemias, lymphomas, tumors, mastocytosis, and atheroembolic disease.

Immunologic Disorders and Reactions

Hyper-IgE syndrome, Omenn’s syndrome, thymomas, and transplant rejections are only a few types of conditions with increased numbers of eosinophils.

Endocrine Disorders

Hypoadrenalism has been associated with increases in the levels of eosinophils in the blood.

Specific Organ Involvement

There are certain conditions where eosinophils have been found to be increased or pathologically present.  

  • Skin and Subcutaneous Disorders

    Atopic dermatitis (eczema), bullous pemphigoid, pemphigus vulgaris, dermatitis herpetiformis, drug-induced lesions, urticaria, eosinophilic panniculitis, angioedema with eosinophilia, Kimura’s disease, Shulman’s syndrome, Well’s syndrome, eosinophilic ulcer of the oral mucosa, eosinophilic pustular folliculitis, and recurrent cutaneous necrotizing eosinophilic vasculitis.

  • Pulmonary Conditions

    Drug / toxin-induced eosinophilic lung disease, Loeffler’s syndrome, allergic bronchopulmonary aspergillosis, eosinophilic pneumonia, Churg-Strauss syndrome, eosinophilic granuloma, and pleural eosinophilia.

  • Gastrointestinal Diseases

    Gastroesophageal reflux, parasitic infections, fungal infections, Helicobacter pylori infections, inflammatory bowel disease (ulcerative colitis and Crohn’s disease), food allergic disorders, protein-induced enteropathy and protein-induced enterocolitis, allergic colitis, celiac disease, pemphigus vegetans (MR) and primary eosinophilic esophagitis, gastroenteritis, and colitis. Rare tumors (leiomyomatosis), connective tissue disorders, and vasculitic disorders.

  • Neurologic Disorders

    Organizing chronic subdural hematoma membranes, central nervous system infections, ventriculoperitoneal shunts, and drug-induced adverse reactions.

  • Cardiac Conditions

    Secondary to systemic disorders such as the hypereosinophilic syndrome or the Churg-Strauss syndrome, heart damage has been reported. Certain congenital heart conditions (septal defects, aortic stenosis) are associated with increased levels of eosinophils in the blood.

  • Renal Diseases

    Eosinophiluria (eosinophils in the urine) is associated with infections or interstitial nephritis and eosinophilic cystitis.

Psychological Effects of Eosinophilic Disorders

Many parents have questions about the psychological effects that an eosinophilic disorder can have on their child. Here are answers, provided by the experts at the Cincinnati Center for Eosinophilic Disorders at Cincinnati Children’s, to some frequently asked questions. Expand the following categories for specific examples:

Common Questions From Families

Questions to ask your Doctor