EFFECT OF ALLERGEN PROVOCATION ON INFLAMMATORY CELL PROFILE AND ENDOTHELIN-LIKE IMMUNOREACTIVITY IN GUINEA-PIG AIRWAYS

The effect of allergen challenge on the number of leucocytes and the c oncentration of endothelin 1-like immunoreactivity (ET-LI) in bronchoa lveolar lavage fluid (BALF) was investigated in guinea-pigs sensitized to Ascaris suum. The animals were twice exposed to allergen aerosol. All animals responded to the second challenge with bronchoconstriction . Twelve hours later, a significant increase in the number of eosinoph ilic granulocytes in BALF, compared to unsensitized and unprovoked con trol animals, was noted. Twenty-four hours after provocation, there wa s also an elevation of ET-LI concentration and content of neutrophils. During the first day post-challenge, the ET-LI values were moderately correlated to the eosinophil levels. One week after challenge, the ET -LI level and the neutrophil count did not differ from corresponding v alues in control animals whereas the number of eosinophils remained el evated. Pretreatment with dexamethasone before the second allergen cha llenge did not consistently affect the parameters studied during the f irst 24 h. Bronchoconstriction induced by carbachol aerosol affected s ignificantly neither the ET-LI concentration nor the number of inflamm atory cells in BALF. It is concluded that the allergen-induced inflamm ation in the guinea-pig airways causes an elevation in the ET-LI conce ntration in BALE and that this is moderately correlated to the influx of eosinophils during the first 24 h.