[Histamine-release: present data and practical interest (author's transl)]

Histamine remains the best known humoral marker of hypersensitivity phenomena. Stored in blood basophilic cells and mast cells this histamine can be released under the influence of an immunitary factor with humoral or cellular mediation or under the dependance of irritative factors either chemical or medicinal. The authors recall the innermost mechanism of the main stages of histamine-release: recognition of membrane receptors, multiple enzymatic activations, opening of calcic membrane pores, synthesis of unpreformed mediators (SRSa and PAF), finally granular extrusion with release of histamine and of numerous mediators, among which the neutrophil chemotactic factor, one of the main responsible ones of the late phase of hypersensitivity phenomena. The regulation of histamine release is mostly done by cyclic AMP and GMP and the membrane receptors H2. The test of histamine release on whole blood or on leucocypte suspension enables by the study of effect-dose curves to differentiate the histamine release mechanisms: bell shaped curve in the case of immunitary processus and ascending curve for an irrative phenomenon. Practically this test can be used for diagnosing drugs allergies, professional asthmas or to study the pharmacological activity of a drug.