Effects of protamine on histamine release from human lung.

Animal mast cell models demonstrate direct histamine release by protamine. Investigators have proposed that protamine also releases histamine in man. We studied the effects of protamine alone and heparin-protamine mixtures on minced lung tissue for evidence of histamine release. We were unable to demonstrate the release of histamine despite positive anti-IgE controls. Nonimmunologic histamine release from human lung appears unlikely as a mechanism for protamine reactions in man.