Hypoxia-inducible factor-1 alpha (HIF-1 alpha) is considered as a key molecule in regulating Th17:regulatory T-cells (Tregs) balance. The aims of this study were to investigate whether HIF-1 alpha is associated with the ROR gamma (RAR-related orphan receptor gamma) expression of Tregs in nasal polyps and to verify whether Staphylococcus enterotoxin B (SEB) is involved in this process.