Immunologic aspects of eosinophilia.
ABSTRACT There is compelling investigative data to indicate that the eosinophil may be more than just coincidentally involved in immune system function. In concert with IgE and the mast cell it is likely that eosinophil actions evolved as an early host defense mechanism against helminth parasites. Thus, a reasonable basis exists for the concept that in the evolutionary scheme there emerged genetically endowed humans with the potential for mounting immediate hypersensitivity responses to multicellular and complex antigenic particulates and animal and plant products, e.g., pollens and danders; hence the atopic state, allergic reactivity and the eosinophil. In many instances there is reason to interpret and ascribe a benign nature to eosinophil accumulations. In other circumstances, associations with hypersensitivity inflammation, for better or for worse, are viewed with special interest by eosinophil watchers as the unraveling of allergic phenomena continues.
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ABSTRACT: In contrast to early epidemiological evidence offering links between eosinophilia-myalgia syndrome (EMS) and microimpurities of L-tryptophan-containing dietary supplements (LTCDS), this account shows why reliance on a finite impurity from one manufacturer is both unnecessary and insufficient to explain the etiology of EMS. Excessive histamine activity has induced blood eosinophilia and myalgia (Greek: mys, muscle + algos, pain). Termination of the multiple actions of histamine is dependent on particular amine oxidases and histamine-N-methyltransferase. Histamine metabolism is rapid when these degradative reactions are operative. The latent effects of incurred histamine can be potentiated and aggravating when these mechanisms are impaired. Overloads of tryptophan supplements cause - among other relevant side-effects - an increased formation of formate and indolyl metabolites, several of which inhibit the degradation of histamine. Moreover, (non-EMS) subjects with hypothalamic-pituitary- adrenal (HPA) axis dysregulation have also manifested greatly increased sensitivities to incurred tryptophan and histamine. A final common pathway for syndromes characterized by eosinophilia with myalgia is now evident.Inflammation Research 12/2005; 54(11):435-50. · 1.96 Impact Factor