Nasal polyp tissues were taken from random patients undergoing nasal polypectomy at the Ajou University Hospital. Atopic status were evaluated before the procedure. Allergy skin prick tests were performed on the backs of the subjects using 80 common inhalant and food allergens (Bencard Allergy Service, Brendford, Middlesex, UK). Positive response was defined on the basis that they showed more than 2+ skin-prick test reactions to two or more common inhalant allergens, such as Dermatophagoides farinae, Dermatophagoides pteronyssinus, alder, oak, rye grass, mugwort, ragweed, Aspergillus spp. Serum specific IgE antibody was determined by radioimmunoassay (DPC, USA).

Atopics were defined as those showing positive responses on skin prick (≥ 2+) and having serum specific IgE antibody to Dermatophagoides pteronyssinus. Non-atopics were defined as those who had all negative responses to common inhalant and food allergens on skin-prick test, and serum total IgE level was less than 100 IU/ml. Ten atopic and 10 non-atopic subjects were enrolled. All the subjects gave their informed consent as regulated by the Ajou University Hospital.

The polyp tissue was frozen at −70°C immediately after the operation. When prepared for the experiments, the samples were thawed, grounded in an homogenizer (POLYTRON, Switzerland) with phosphate buffered saline (PBS, pH 7.5) including 1% triton X-100. They were centrifuged and the separated supernatant had been kept at−70°C.

Albumin levels in the polyp tissue were measured by nephelometry¹⁰⁾ with a Beckman Array system (Beckman instruments inc., Brea, Calf.). Serum albumin was measured By Bromocresol green method¹¹⁾.

Serum total IgE was measured by radio-immunoassay (DPC, USA).

The levels of total IgE in polyp tissue were measured by sandwich ELISA. Microtiter plates (Immulon II; Dynatech Laboratories, Inc., Chantilly, VA) were coated with affinity-purified goat anti-IgE antibody (Vector Laboratories, Inc., Burlingame, CA) at 1:500 dilution (1 mg/ml) with 0.1M carbonate, pH 9.6, for 2hours at 4°C. Plates were washed and blocked with 3% bovine serum albumin in Tween-20-PBS, and then the plates are incubated with duplicated samples (50 μ l) of polyp tissue homogenate and IgE standard (DPC, USA) diluted in blocking buffer for 2 hours at 4°C. After repeated washing, the plates were incubated with biotinylated affinity-purified goat anti-IgE antibody (Vector Laboratories, Inc., Burlingame, CA) at 1:500 dilution (1 mg/ml) for 1 hour at room temperature. After washing again, plates were incubated with streptavidin-peroxidase (0.5 mg/ml) for 30mins at room temperature. After washing, the substrate solution was added, consisting of 0.04%(w/v) O-phenylene diamine dissolved in 24.3 mM citric acid, 51.4 mM NaH₂PO₄ (pH 5.0) and 0.03% H₂O₂. After 30 min, the reaction was stopped by adding 2.5 N H₂SO₄. The absorbance value at 490 nm was measured by a microplate reader (Molecular device, USA). The absolute level of total IgE in the sample was calculated from the curve derived from serial dilution of IgE standard (DPC, USA). All samples were measured simultaneously to reduce the variation of measurement.

The Mann-Whitney U-test was used to assess differences between two groups. Spearman’s rank correlation test was used to assess the correlation between two data. A p-value of less than 0.05 was considered significant.

Fig. 1 shows the comparison of albumin level in both serum and nasal polyp tissue between atopic and non-atopic subjects. There were no significant differences in the albumin levels between the two groups, respectively (p>0.05).

When the serum total IgE level was presented as the ratio of total IgE/albumin, serum total IgE/albumin ratio was significantly higher in atopic subjects than in non-atopic subjects as shown in Fig. 2 (p=0.00). When the total IgE level in the nasal polyp tissue was presented as total IgE/tissue albumin ratio, tissue total IgE/albumin ratio was significantly higher in atopic subject than in non-atopic subject (Fig. 2; p<0.05). Three of non-atopic subjects as well as eight of atopic subjects had remarkably high tIgE/albumin (greater than 10). The ratio of tissue total IgE/albumin against serum total IgE/albumin was higher than 1 in all the non-atopic subjects and seven of 10 (70%) atopic subjects as shown in Fig. 3. Serum total IgE/albumin ratio was significantly correlated with tissue total IgE/albumin ratio (Fig. 4; r=0.46, p<0.05).