[Effect of cytokines and fibroblasts on eosinophilic granulocyte survival in polyposis nasi].

BACKGROUND

Eosinophilic infiltration is the most prominent histologic feature of nasal polyps. The effects of eosinophil-associated cytokines and fibroblast derived factors on survival of isolated eosinophils from blood of patients with nasal polyps were investigated.

METHODS AND PATIENTS

Peripheral blood eosinophils of 9 patients with nasal polyps were incubated in 1. culture medium alone and in a medium containing, 2. IL-5 (10 pg/ml); 3. IL-3, IL-5, GM-CSF (10 pg/ml); 4. supernatants of fibroblasts cultured from polyps of the same 9 patients; and 5. supernatants of fibroblasts enriched with IL-5, -3, and GM-CSF. Viability of eosinophils was assessed by their ability to take up WST-1.

RESULTS

The survival index (T50) of eosinophils cultured in different culture medium is listed as follows: 1. medium alone: 0.8 +/- 0.14 days (MV +/- SEM), 2. medium containing IL-5; 1.2 +/- 0.19 days, 3. medium containing IL-3, IL-5, and GM-CSF: 3.1 +/- 0.13 days, 4. fibroblast supernatants: 1.6 +/- 0.29 days, and in 5. fibroblast supernatants enriched with IL-3, IL-5 and GM-CSF: 2.2 +/- 0.21 days.

CONCLUSION

IL-5, prolongs eosinophil survival in vitro, IL-3, IL-5 and GM-CSF revealed synergistic effects; survival of eosinophils was significantly prolonged in comparison to stimulation with IL-5 alone. Supernatants of fibroblasts also prolonged eosinophil survival. This effect is probably due to GM-CSF, which was found in high concentrations in fibroblast supernatants.