The effect of corticosteroids on monocyte and neutrophil activation in bronchial asthma

Abstract

The expression of IgG (Fc) receptor (FcR) and complement receptor (CR) on peripheral blood monocytes and neutrophils was determined by the rosette technique in patients with asthma receiving different forms of treatment. In 31 patients taking inhaled therapy (i.e., bronchodilators alone or in combination with inhaled corticosteroids), monocyte FcR (48.19 ± 1.24%, mean ± SEM) and complement (66.54 ± 1.09%) rosettes were significantly higher (FcR p < 0.001, CR p < 0.001) than in the 17 healthy, normal control subjects (FcR 37.94 ± 0.82%, CR 59.7 ± 0.98%). These increases in the percent rosettes between the two groups were observed even when a wide concentration range of IgG or complement was used to coat the red cells. No significant differences in monocyte receptor expression were observed between those patients being treated with bronchodilators alone or patients being treated in combination with inhaled corticosteroids. In 19 patients with asthma receiving oral corticosteroids, the mean monocyte FcR (38.21 ± 1.73%) and CR (52.78 ± 2.09%) were significantly reduced when these patients were compared with those patients receiving inhaled therapy alone (FcR p < 0.001, CR p < 0.001), and there was a significant inverse correlation between the percent rosettes and the dose of prednisolone. Neutrophil CR (51.32 ± 1.30%, p < 0.05) but not FcR expression (24.7 ± 0.80%) was significantly increased when these were compared with those of control subjects (FcR 24.7 ± 0.60%, CR 47.11 ± 0.86%), and both neutrophil FcR and CR expression was significantly reduced (FcR p < 0.01, CR p < 0.001) in those patients with asthma receiving oral corticosteroids. There was also a significant correlation between monocyte FcR expression and the percent predicted FEV 1 measurements in the prednisolone-treated group with asthma (r = −0.62, p < 0.02). These results suggest that circulating monocytes and neutrophils are activated in patients with bronchial asthma and that oral corticosteroids reverse this effect.