Elevation of soluble interleukin-2 receptor levels in nasal allergy

To investigate soluble IL-2 receptor (sIL-2R) levels in nasal allergy, the sera and nasal secretions from patients with nasal allergy and from healthy subjects were subjected to a double-epitope enzyme-linked immunosorbent assay. Significant elevation of sIL-2R concentrations in the sera and nasal secretions was observed in the allergy patients (n = 26) compared with those of healthy subjects (n = 9). IL-2R-positive (CD25(+)) cells were observed in the crust formed in an allergic nasal mucosa. The concentration of sIL-2R in the sera correlated neither with the eosinophil count of the peripheral blood count nor with clinical severity. The concentration of sIL-2R in the nasal secretions was significantly higher compared with that in the sera from allergic patients (p < 0.01), whereas no significant difference was observed between sIL-2R levels in the sera and nasal sections from normal subjects. These findings indicate that sIL-2R plays an essential role in allergic processes by regulating IL-2R-positive cells recruited into the nasal mucosa.