The Influx of Inflammatory Cells into Nasal Washings during the Late Response to Antigen Challenge: Effect of Systemic Steroid Pretreatment

Abstract

Previous studies have demonstrated symptoms and mediator release occurring as long as 11 h after nasal challenge with antigen in selected allergic subjects. Pretreatment with systemic steroids reduced symptoms and mediators including histamines, TAME-esterasse activity, and kinins. The aims of the present study were to characterize the cell influx during the late-phase response to antigen challenge and to determine the effect of pretreatment with systemic steroids on this response. We examined cytospin slides of nasal washings obtained before and hourly for 11 h after nasal antigen challenge in 10 asymptomatic allergic subjects with a history of seasonal rhinitis and 5 normal, nonallergic subjects. Allergic subjects received oral prednisone (20 mg 3 times a day) or placebo in a random, double-blind crossover manner for 2 days before each of 2 challenges 1 month apart. On placebo days, a mixed cell influx occurred in allergic subjects during the late response that was 50-fold greater than the cell influx in the nonallergic control subjects (p < 0.005). During the first 3 h after antigen challenge, eosinophils (p < 0.005), but not neutrophils or mononuclear cells were all observed. During the late phase (4 to 11 h), neutrophils, eosinophils, and mononuclear cells were all increased. Oral steroid pretreatment blocked the influx of eosinophils (p < 0.005), but not that of other cells. These data demonstrate an inflammatory cell influx associated with the nasal late-phase response and suggest an important pathogenetic role for the eosinophil. The previously observed reduction in mediators during the late response with systemic steroid pretreatment is most likely due to an altered cell influx but may also involve altered inflammatory cell function.