Eosinophil diamine oxidase activity in acute inflammation in humans.

Eosinophil diamine oxidase, histaminase, activity was assayed in acute inflammatory states and correlated to disease activity. Correlation to serum and urine histamine, metabolites of histamine and granulocyte histamine metabolizing enzymes was also studied. Using a radiochromatagraphic assay, diamine oxidase, histaminase, activity was determined in human peripheral blood eosinophils from patients with acute inflammatory states including active asthma, cold-induced urticaria and parasitic infestation; eosinophils from non-active asthmatic patients and normals were used as controls. Eosinophils were purified over a metrizamide discontinuous (16-30%) gradient. Total eosinophils were purified over a metrizamide discontinuous (16-30%) gradient. Total eosinophil histaminase activity was increased two- to three-fold in patients with active disease and returned to lower levels in eosinophils from patients without active disease or with treated disease. Thus, the induction of eosinophil histaminase might be a control mechanism for the inflammation induced by histamine during these acute inflammatory states.