Objective: This study was conducted to investigate the expression of alpha IL5 and alpha GM-CSF receptors (alpha IL5r and alpha GM-CSFr) mRNA in the paranasal sinus mucosa of atopic and nonatopic subjects with chronic sinusitis compared to controls.
Design: This was a prospective study of patients presenting with the diagnosis of chronic sinusitis of at least 6 months' duration.
Method: Fourteen patients with stable chronic sinusitis (7 atopic, 7 nonatopic) and 7 controls were included, from whom sinus mucosal biopsies were obtained and examined for membrane-bound alpha IL5r and alpha GM-CSFr mRNA using in situ hybridization.
Results: There was a significant difference in the number of cells expressing alpha IL5r mRNA per high-power field in both atopic and nonatopic subjects compared to controls, and in the number of cells expressing alpha GM-CSFr mRNA in both atopic and nonatopic subjects compared with controls. The number of alpha IL5r mRNA-positive cells was significantly greater in the atopic versus nonatopic groups, whereas alpha GM-CSFr mRNA-positive cells were greater in number in the nonatopic versus atopic groups.
Conclusion: Both alpha IL5r and alpha GM-CSFr are upregulated in chronic sinusitis, suggesting that increases in both Th-2 cytokines and their receptors may be important in the pathology of the disease. Furthermore, the predominant associations of alpha IL5r with atopic chronic sinusitis and alpha GM-CSFr with nonatopic chronic sinusitis suggest that the chronic inflammation in this condition may arise from differential activation of distinct cytokine pathways depending on whether or not there is associated atopy.