Bacteria and their products release histamine and potentiate mediator release: new aspects in airway diseases.

The possibility that bacteria and their products play a role in airway diseases, due to their capacity to release histamine, was investigated in blood leucocytes from patients suffering from respiratory diseases and from healthy individuals. The results clearly show that bacteria release histamine by immunological and non-immunological mechanisms and that endotoxins enhance mediator release caused by allergens in allergic patients or by bacteria in persons sensitized to these organisms. Furthermore, a great increase is obtained in mediator release by the combination of immunological and non-immunological mechanisms.