NEUTROPHILIC RESPIRATORY-TRACT INFLAMMATION AND PERIPHERAL-BLOOD NEUTROPHILIA AFTER GRAIN-SORGHUM DUST EXTRACT CHALLENGE

Study objective: To determine if inhalation of grain sorghum dust in t he laboratory would cause neutrophilic upper and lower respiratory tra ct inflammation in human volunteers, as well as systemic signs of illn ess. Design: Prospective. Setting: University of Nebraska Medical Cent er. Participants: Thirty normal volunteers. Interventions: Inhalation challenge with 20 mt of a nebulized solution of filter-sterilized grai n sorghum dust extract (GSDE), One group received prednisone, 20 mg fo r 2 days, prior to the challenge. Measurements and results: Bronchosco py with bronchoalveolar lavage (BAL) was performed 24 h after challeng e, with samples collected as bronchial and alveolar fractions, Finding s included visible signs of airways inflammation, quantified as the br onchitis index, The percentage of bronchial neutrophils was significan tly increased in those challenged with GSDE vs the control solution, H anks' balanced salt solution (40.3+/-4.5% vs 14.3+/-5.1%, p less than or equal to.01), Similar findings were seen in the alveolar fraction, Pretreatment with corticosteroids did not prevent the rise in neutroph ils recovered by BAL, Peripheral blood neutrophils were also increased in volunteers challenged with the grain dust extract, To explain the increase in peripheral blood neutrophil counts, the capacity of the pe ripheral blood neutrophils to migrate in chemotaxis experiments was ex amined, The results demonstrate an increase in peripheral blood neutro phils and an increase in chemotactic responsiveness. Conclusions: Inha lation challenge with a grain dust extract causes respiratory tract in flammation and a peripheral blood neutrophilia. One reason for this ma y be an increase in activated peripheral blood neutrophils.