Differential pattern of human blood neutrophil activation after stimulation with organic dust in vitro and in vivo.

Abstract

To study activation of blood neutrophils in subjects after in vitro and in vivo stimulation. Blood from healthy volunteers was collected before and after their exposure to organic dust in a pig farm. Surface markers of neutrophil activation were analyzed by flow cytometry. In vivo, there was a diurnal variation in basal levels of CD11b. Swine dust exposure increased the number of blood neutrophils and the levels of myeloperoxidase without effects on CD11b or Cys-X-Cys receptor 1 (CXCR-1) expression. However, a positive correlation between changes of myeloperoxidase and CD11b expression was observed. In vitro, N-formyl-methionyl-leucyl-phenylalanine (fMLP), lipopolysaccharide (LPS), leukotriene (LT)B4, LTD4, and swine dust stimulated the expression of CD11b. fMLP, LPS, and LTB4 diminished the expression of CXCR-1. Exposure to swine dust in vitro activated neutrophils and inhalation of swine dust caused neutrophilia.