Expression of the cysteinyl leukotriene receptors cysLT1 and cysLT2 in aspirin-sensitive and aspirin-tolerant chronic rhinosinusitis

Background: Cysteinyl leukotrienes play a disease-regulating role in rhinosinusitis and asthma, particularly aspirin-sensitive disease. They act through 2 G-protein coupled receptors termed cysteinyl leukotriene type 1 receptor (cysLT(1)) and cysteinyl leukotriene type 2 receptor (cysLT(2)). We previously compared expression of cysLT(1) on mucosal leukocytes in patients with aspirin-sensitive and aspirin-tolerant rhinosinusitis. Objective: To compare expression of cysLT(1) and cysLT(2) on leukocytes, mucus glands, and epithelium in 32 patients with chronic polypoid rhinosinusitis (21 aspirin-sensitive, 11 aspirin-tolerant) and 9 normal controls. Methods: Total numbers of CD45(+) leukocytes, percentages of these cells expressing cysLT(1) or cysLT(2), and percentages of the total epithelial and glandular areas expressing cysLT(1) or cysLT(2) were measured in sections of nasal biopsies by using immunohistochemistry and image analysis. Results: The percentages of mucosal CD45(+) leukocytes expressing cysLT(1) were significantly (P < .0001) elevated in the aspirin-sensitive but not the aspirin-tolerant patients compared with the controls. In contrast, the percentages of leukocytes expressing cysLT(2) did not differ significantly in the 3 groups. On epithelial and glandular cells, expression of cysLT(2) significantly exceeded that of cysLT(1) in both the patients With rhinosinusitis and the controls (P less than or equal to .004), although there was no significant difference in the expression of either receptor in the patients with rhinosinusitis (aspirin-sensitive or aspirin-tolerant) and the controls. Conclusion: Although cysLT(1) expression predominates on inflammatory leukocytes in patients with aspirin-sensitive rhinosinusitis, the effects of cysteinyl leukotrienes on glands and epithelium may be mediated predominantly through cysLT(2). This has potentially important therapeutic implications.