The Eosinophil Leukocyte

Eosinophil precursors originate in the bone marrow, where they divide and further differentiate into mature eosinophils, which shortly circulate in the bloodstream, and get recruited into target tissues such as the lung through cell attraction and adhesion to the endothelial cells (through adhesion molecules), diapedesis, and chemotaxis within tissues. Eosinophil recruitment to tissues 

Eosinophilic pneumonias of parasitic origin and other infectious causes Allergic bronchopulmonary aspergillosis and related syndromes Iatrogenic and toxic agents-induced eosinophilic pneumonias Drugs 

Eosinophilic lung disease of undetermined origin Limited to the lung 

Idiopathic chronic eosinophilic pneumonia Idiopathic acute eosinophilic pneumonia Associated with systemic disease Churg-Strauss syndrome 

Lung diseases with possible and/or mild pulmonary eosinophilia Asthma, eosinophilic bronchitis Organizing pneumonia Idiopathic interstitial pneumonias Langerhans cell granulomatosis Sarcoidosis Lymphoma 

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Gleich G, Adolphson C. 1986. The eosinophilic leukocyte Structure and function. Adv Immunol. 39 177-253. 

Gleich, G.J., Motojima, S., Frigas, E., Kephart, G.M., Fujisawa, T. and Kravis, L.P. (1987). The eosinophilic leukocyte and the pathology of fatal bronchial asthma evidence of pathologic heterogeneity. J. Allergy Clin. Immunol. 80, 412-415. 

GLEICH, G.J. ADOLPHSON, C.R. (1986) The eosinophilic leukocyte structure and function. Advances in Immunology, 39, 177-253. 

Eosinophils, which constitute only 1 to 4% of the total number of white blood cells, are only weak phagocytes. These leukocytes are produced in large numbers in individuals with internal parasitic infections. The eosinophils attach to the parasites and secrete substances that kill them, including ... 

Basophils and Eosinophils. These two types of granulocyte represent only a small proportion of the circulating leukocytes. The basophil possesses receptors specific for the Fc portion of IgE molecules. It is involved in allergic reactions and can play a role in the clinical state of anaphylaxis, which is a life-threatening allergic response. Eosinophils are involved with the immune reactivity of drug allergies and with the body s immune response to parasitic infestations such as worms (see chapter 9). 

Not all classes of leukocytes are affected by glucocorticoids in the same way. The total leukocyte count is increased, but the number of eosinophilic leukocytes falls, as does the lymphocyte count. The number of monocytes is reduced, as is their capacity to perform phagocytosis. 

Bozeman, P.M., Leam, B.B., and Tomas, E.L., Assay of the human leukocyte enzymes myeloperoxidase and eosinophil peroxidase, J. Immunol. Methods, 126, 125-133, 1990. 

Lipoxygenases may act at carbons 5, 12, or 15. The type of lipoxygenase varies from tissue to tissue. For example, polymorphonuclear leukocytes contain primarily 5-lipoxygenase, platelets are rich in 12-lipoxygenase, and eosinophilic leukocytes contain primarily 15-lipoxygenase. 

Inflammation of the airway is the peculiar pathological abnormality in asthma (Hegele and Hogg, 1996). Inflammatory responses are associated with the accumulation of numerous cells including lymphocytes, macrophages, and plasma cells in the lamina propria (Laitinen et ah, 1993). Further, more of those cells are found in fhe adventitial connective tissues of outer wall of smaller airways (Haley et ah, 1998). Moreover, the airway epithelium is infiltrated by the numerous leukocytes eosinophils are prominent among them. 

From this table, it is clear that the asthmatics differed from the healthy subjects in the number of leukocytes, T cells, and eosinophils in these larger airways. Azzawi and colleagues also correlated the number of eosinophils present and the duration of the terminal episode, which ranged from a few hours to several days. The longer the duration, the higher the eosinophil count in the airways (30). 

Eosinophilic gastroenteritis is characterized by infiltration of the gut by eosinophil leukocytes. There appear to be at least two distinct groups one in which the infiltrate is predominantly superficial, which is associated with atopy and in which food hypersensitivity can often be demonstrated, and another in which the infiltrate is most marked in the deeper submucosal, muscle, and serosal layers, but which does not appear to be associated with atopy or demonstrable food hypersensitivity. 

Asthma is a common cause of mild increase of eosinophils in peripheral blood and BAL differential cell counts (usually <5%), in the absence of eosinophilic pneumonia. Eosinophilia may also be found in induced sputum, a finding that may help in adapting the treatment and reduce asthma exacerbations and hospital admissions. Eosinophilic inflammation of the bronchial walls is very common at histopathology in asthmatics (45) and has been correlated with the severity of asthma, defining the eosinophilic variant of asthma (as opposed to the neutrophilic and pauci-leukocytic variants of asthma). The eosinophilic variant of asthma often begins late in adulthood, may be associated with aspirin intolerance, and may respond poorly to inhaled corticosteroids. 

Isabel, T. C. Del, C. R Carlos, S. J. Influence of inorganic salts on the staining reaction of eosinophil leukocyte granules by anionic dyes. Acta Histochem. 1992, 93, 313-318. 

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