A mononuclear cell-derived histamine releasing factor in asthmatic patients. II. Activity in vivo

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.