The effect of passive sensitisation of human bronchial smooth muscle on in vitro sensitivity to histamine.

Allergen exposure may precipitate acute bronchoconstriction and increase bronchial reactivity. We have investigated whether passive sensitisation of human airway per se or short-term exposure to mediators released by specific antigen exposure produces an alteration in in vitro smooth muscle sensitivity to histamine. Exposure to allergen produced smooth muscle contraction in sensitised tissue, but subsequent smooth muscle sensitivity to histamine was not altered. We conclude that neither passive sensitisation nor short-term exposure to mast cell mediators alters in vitro smooth muscle sensitivity to histamine.