Leukotriene receptor antagonist pranlukast suppresses eosinophil infiltration and cytokine production in human nasal mucosa of perennial allergic rhinitis

The purpose of this study was to investigate the influence of pranlukast on eosinophilic inflammation and cytokine production in human nasal mucosa. Twelve patients were treated with pranlukast, and samples were obtained from the nasal mucosa of the inferior turbinate. With respect to cell infiltration, a significant decrease was observed in the percentage of inflammatory cells (secreted eosinophil cationic protein [EG2] and neutrophil elastase) after treatment. The levels of cytokines and chemical mediators (interleukin [IL]-4, IL-5, RANTES [regulated on activation, normal T cell expressed and secreted], cysteinyl leukotrienes, IL-1beta, tumor necrosis factor-alpha, and IL-8) assessed by enzyme-linked immunosorbent assay and enzyme immunoassay were significantly decreased. These results indicate that pranlukast decreased the levels of a majority of the cytokines in nasal mucosa, leading to improvement in subjective nasal symptoms. Furthermore, these results support the hypothesis that pranlukast exerts its therapeutic action primarily by blocking the leukotriene receptors on eosinophils.