Cultured nasal polyps from nonatopic and atopic patients release RANTES spontaneously and after stimulation with phytohemagglutinin

Background: Eosinophil infiltration of tissue is a hallmark of nasal polyposis in both nonatopic and atopic patients. These cells are thought to play a key role in the nasal polyp inflammatory process. Objective: The objective of this study was to investigate whether cultured nasal polyps derived from nonatopic and atopic patients release RANTES both spontaneously and after phytohemagglutinin (PHA) stimulation. Methods: Nasal polyps were obtained from 12 subjects (6 nonatopic and 6 atopic), cut into 2 to 3 mm large specimens, and cultured for 48 hours with or without PHA. RANTES was measured in the culture supernatant by ELISA (R and D Systems, U.K.). Results: Immunoreactive RANTES was found to be present in the culture supernatant of nasal polyps derived from both nonatopic and atopic patients with no difference between the two groups (median: 3.8 vs 2.9 pg/mg/ml). On incubation with PHA, nasal polyps from both nonatopic and atopic patients released sevenfold and 11-fold greater amounts of RANTES than unstimulated samples. As determined by immunohistochemistry, RANTES was localized to the vascular endothelium in nasal polyps from both groups of patients. Conclusions: This study demonstrates that cultured nasal polyps derived from both nonatopic and atopic patients release RANTES spontaneously and after PHA stimulation. This observation and the finding that RANTES is present in nasal polyp endothelial cells suggest that this chemokine may be an important mediator of eosinophil and lymphocyte recruitment in both nonatopic and atopic nasal polyposis.