Lymphocyte-variant hypereosinophilia

Lymphocyte-variant hypereosinophilia is a rare disorder in which eosinophilia or hypereosinophilia (i.e. a large or extremely large increase in the number of eosinophils in the blood circulation) is caused by an aberrant population of lymphocytes. These aberrant lymphocytes function abnormally by stimulating the proliferation and maturation of bone marrow eosinophil-precursor cells termed colony forming unit-Eosinophils or CFU-Eos. The overly stimulated CFU-Eos cells mature to apparently normal appearing but possibly overactive eosinophils which enter the circulation and may accumulate in and damage various tissues. The disorder is usually indolent or slowly progressive but may proceed to a leukemic phase sometimes classified as acute eosinophilic leukemia. Lymphocyte-variant hypereosinophilia can therefore be regarded as a precancerous disorder. The disorder merits therapeutic intervention to avoid or reduce eosinophil-induced tissue injury and treat its leukemic phase. The latter phase is aggressive and typically responds relatively poorly to anti-leukemia chemotherapeutic drug regimens. The typical patient with lymphocyte-variant hypereosinophilia presents with an extended history of hypereosinophilia and cutaneous allergy-like symptoms. Skin symptoms, which occur in >75% of patients, include erythroderma, pruritus, eczema, Poikiloderma, urticarial, and episodic angioedema. The symptom of episodic angioedema (i.e. soft tissue swelling of the face, tongue, larynx, abdomen, arms, or legs) in lymphocyte-variant hypereosinophilia resembles that occurring in Gleich's syndrome, a rare disease that is accompanied by secondary hypereosinophilia plus a sub-population of CD3(-), CD4(+) T cells; this involvement of the latter cell types supports the notion that Gleich's syndrome is a subtype of lymphocyte-variant hypereosiophilia. Biopsies of skin lesions commonly find prominent accumulations of eosinophils.

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Concepts associés (5)

Eosinophilic myocarditis

Eosinophilic myocarditis is inflammation in the heart muscle that is caused by the infiltration and destructive activity of a type of white blood cell, the eosinophil. Typically, the disorder is associated with hypereosinophilia, i.e. an eosinophil blood cell count greater than 1,500 per microliter (normal 100 to 400 per microliter). It is distinguished from non-eosinophilic myocarditis, which is heart inflammation caused by other types of white blood cells, i.e.

Clonal hypereosinophilia

Clonal hypereosinophilia, also termed primary hypereosinophilia or clonal eosinophilia, is a grouping of hematological disorders all of which are characterized by the development and growth of a pre-malignant or malignant population of eosinophils, a type of white blood cell that occupies the bone marrow, blood, and other tissues. This population consists of a clone of eosinophils, i.e. a group of genetically identical eosinophils derived from a sufficiently mutated ancestor cell.

Lymphocyte-variant hypereosinophilia