A Mononuclear Cell‐Derived Histamine Releasing Factor in Asthmatic Patients

In an attempt to study the role of lymphokines in asthma, lymphocytes from asthmatic patients were stimulated in vitro with skin test-positive allergen (dust mite) or with non-specific mitogen-phytohaemagglutinin for 4 h, then washed carefully and cultured alone for 16 h. Cell-free supernatants were subsequently collected and applied in the basophil histamine release test in vitro and in bronchial provocation test and skin prick test in vivo. Supernatant of non-stimulated lymphocytes from asthmatic patients released significant amounts of histamine from basophils. Stimulation of lymphocytes with specific allergen or phytohaemagglutinin augmented the supernatant-induced histamine release. Lymphocyte supernatants from the majority of patients also induced bronchoconstriction and elicited skin wheal and flare reaction in vivo.