HUMAN BASOPHIL MAST-CELL RELEASABILITY .11. HETEROGENEITY OF THE EFFECTS OF CONTRAST-MEDIA ON MEDIATOR RELEASE

Background: The activation of basophils and mast cells plays a role in the pathogenesis of anaphylactoid reactions occurring during the admi nistration of iodinated radiocontrast media. Methods: We compared the effects of three contrast media (CM), Hexabrix (sodium and meglumine s alts of ioxaglic acids), Telebrix (sodium and meglumine salts of ioxit alamic acid), and Optiray (ioversol) on the release of performed (hist amine and tryptase) and de novo synthesized (prostaglandin D-2 and leu kotriene C-4) mediators from human basophils and mast cells isolated f rom lung, skin, and heart tissue. The commercial preparations were eva luated in parallel with the pure substances. Mannitol was used a posit ive control inducing histamine release (HR) by hyperosmolar stimulatio n. Results: Hexabrix (0.1 to 0.3 mol/L), Telebrix (0.1 to 0.5 mol/L), Optiray (0.2 to 0.5 mol/L), and the corresponding pure substances conc entration-dependently induced HR from basophils. A positive correlatio n was found between CM osmolality and HR from basophils. Mast cells is olated from different anatomic sites responded differently to the thre e CM. Hexabrix and Optiray induced histamine and trytase release from human lung mast cells, but not from human skin mast cells. No correlat ion was found between the osmolality of CM and HR from human lung mast cells. There was a significant correlation between the percent of his tamine and tryptase release induced by CM from human lung mast cells. None of the CM induced the de novo synthesis of Leukotriene C-4 or pro staglandin D-2 from basophils or mast cells. The kinetics of HR caused by CM differed according to the drug used and the cell (basophils or human lung mast cells) examined. CM-induced HR from basophils and huma n lung mast cells was temperature-dependent, partially influenced by e xtracellular Ca2+ concentrations, and mot modified by preincubation of basophils with IL-2 or IL-3. Conclusion: These results provide eviden ce of the heterogeneity of the effects of CM on mediator release from human basophils and mast cells from different anatomic sites. They als o suggest that hyperosmolarity may be an important factor in the activ ation of basophils by CM, but less relevant for mast cells. CM induce only the release of performed mediators. The measurement of plasma try tase might be clinically useful for monitoring adverse reactions cause d by CM.