Measurement of inflammatory mediators of mast cells and eosinophils in native nasal lavage fluid in nasal polyposis

Background: Nasal polyposis (NP) often coexists with asthma, rhinitis and s inusitis. Polyp histology typically shows chronic, eosinophilic inflammatio n. The inflammatory cell infiltrate generally includes eosinophils, lymphoc ytes, plasma cells and mast cells. Objective: To gain insight into the natu ral history of NP, we analysed mediator levels and leukocyte values in nasa l fluids and eosinophil cationic protein (ECP), total IgE levels and eosino phils in the blood in several groups of both allergic and non-allergic pati ents with nasal polyps and in patients with allergic rhinitis (AR). Methods : Thirty-two patients with nasal polyps entered the study. As a control gro up, we studied 55 patients with AR, i.e. 20 patients with seasonal AR to gr ass pollen, 24 with AR sensitive to Parietaria and 11 with AR sensitive to house dust mite (HDM). Eighteen patients with nasal polyps were also allerg ic patients (8 were sensitive to Parietaria and 10 were sensitive to HDM), whereas 14 were non-allergic patients. Tryptase and histamine values were a ssayed in nasal fluids, whereas total IgE was determined in serum. ECP valu es were assayed both in nasal fluids and serum. Eosinophils were quantified both in the blood and nasal fluids. Results: Tryptase levels were signific antly higher in the nasal lavages from patients with NP than in those from patients without NP (4.7 vs. 3.5 U/I, p < 0.001) and correlated with sympto m scores (r(s) = 0.42, p < 0.0001). The median levels of histamine in nasal fluids from patients with NP were also significantly higher than those obs erved in patients without NP (50.0 vs. 21.3 ng/ml, p < 0.001), but did not correlate with symptom scores. Finally, the median levels of ECP in nasal f luids from patients with NP were significantly higher than those observed i n patients without NP (38.1 vs. 16.1 ng/ml, p < 0.001) and correlated with symptom scores (r(s) = 0.38, p < 0.001). Analysis of variance showed that, among the variables studied, the presence of nasal polyps was the factor re sponsible for the higher levels of tryptase, histamine and ECP in nasal flu ids. With regard to leukocyte counts in nasal fluids, no significant differ ences were observed between rhinitis patients with NP and those without NP. With regard to serum ECP and serum total IgE, no significant differences w ere detected between the two groups under study. Blood eosinophil levels in patients with NP were significantly higher than those observed in patients without NP (5.8 vs. 5.6, p = 0.002). Analysis of variance showed that both the presence of nasal polyps and the type of sensitisation were important. Considering the total symptom scores, no significant differences were obse rved between rhinitis patients with NP and those without NP. Conclusions: T he present findings are consistent with the view that chronic eosinophil mu cosal inflammatory disease in NP involves a self-sustaining mechanism, i.e. local release of inflammatory mediators, independent of allergen stimulati on of nasal mucosa. Increased release of inflammatory mediators contributes to the development of nasal polyps, determining oedema and an increased re cruitment of inflammatory cells. Besides eosinophils, mast cells also play a key role in this process. Copyright (C) 2001 S. Karger AG, Basel.