VCAM-1 and eosinophilia in diffuse sino-nasal polyps.

The objective of our study was to investigate: the expression of vascular cell adhesion molecule-1 (VCAM-1) in diffuse sino-nasal polyps; the relation between VCAM-1 and selective eosinophilia in diffuse sino-nasal polyps; the effect of eosinophilia and VCAM-1 expression on recurrence of diffuse sino-nasal polyps following treatment. Fifty patients with diffuse sino-nasal polyps were included in the study. Biopsies were taken from the polyps and the inferior turbinate mucosa of each patient and were studied by immunohistochemical staining for detection of VCAM-1 expression on the blood vessels, as well as by hematoxylin and eosin (H&E) staining for detection of eosinophils. The percentage of blood vessels expressing VCAM-1 and the number of eosinophils in the polyps were detected and correlated and then compared to the corresponding numbers in the inferior turbinates. All patients were treated by endoscopic ethmoidectomies followed by local steroids for 1 year. Recurrence of polyps was monitored during the post-operative follow-up period. The quantitative expression of VCAM-1 and number of infiltrating eosinophils were compared in patients who developed recurrent polyps and those who did not. VCAM-1 was expressed in the polyps but not significantly higher than in the inferior turbinates of the patients or the controls. Eosinophils were significantly higher in the polyps compared to the inferior turbinates. No correlation was found between the expression of the VCAM-1 and the number of eosinophils. VCAM-1 expression was significantly higher in patients developing recurrent polyps. No significant difference was found in the number of infiltrating eosinophils between patients developing and those not developing recurrent polyps. VCAM-1 is expressed in polyps but not significantly higher than its expression in the inferior turbinate mucosa. VCAM-1 expression in diffuse sino-nasal polyps cannot on its own explain the selective eosinophilia detected in this disease. High VCAM-1 expression in diffuse sino-nasal polyps may be an indicator of a higher probability of polyps recurrence. Degree of eosinophilic infiltration cannot be taken as such an indicator.