[Eosinophil chemoattractants and related factors in nasal polyps]

In vitro studies and animal experiments have shown that cytokines and chemokines are closely related to eosinophil migration, activation, and survival. It remains controversial, however, whether some chemokines or cytokines are actually responsible for the accumulation of eosinophils in nasal polyp tissues. We studied cytokines and chemokines in nasal polyp tissues taken from patients with chronic rhinosinusitis to clarify the pathogenesis of eosinophil accumulation.

Nasal polyp tissues obtained from 20 patients with chronic rhinosinusitis were studied. Concentrations of interleukin (IL-) 5, IL-13, eotaxin, regulated upon activation in normal T cell expressed and secreted (RANTES), and thymus and activation-regulated chemokine (TARC) in homogenates of polyp tissues were measured by ELISA. Nasal polyp tissues were stained by hematoxillin and eosin and were immunostained by an antibody against EG2. The numbers of eosinophils and immunopositive cells for EG2 in the submucosal layer were counted using a microscope.

No significant differences were seen in the numbers of eosinophils and EG2-positive cells, or in the concentration of IL-5, eotaxin, TARC, RANTES in nasal polyp tissues between patients with and without atopic predisposition. Significant positive correlations existed, however, between the number of eosinophils and IL-5, eotaxin, and TARC concentration. IL-13 concentration was below detection in all patients.

We hound that IL-5, eotaxin, and TARC may play an important role in the accumulation of eosinophils in nasal polyps regardless of the presence of atopic predisposition.