Intranasal heparin reduces eosinophil recruitment after nasal allergen challenge in patients with allergic rhinitis

Background: Recently, several studies have shown that heparin possesses var ious anti-inflammatory and antiallergic properties, It has been proposed th at heparin might play an important role in limiting the inflammatory events associated with asthma and allergic rhinitis by neutralizing inflammatory mediators, such as eosinophil cationic protein and major basic protein, and by limiting eosinophil recruitment. Objective: To test the hypothesis that heparin can limit the extent and mag nitude of eosinophilic inflammation, we examined the effect of inhaled intr anasal heparin on nasal response to allergen challenge in 10 patients with allergic rhinitis. Methods: The capacity of heparin to reduce nasal response was studied by ev aluating symptom score, eosinophil cationic protein concentration, and eosi nophil counts in nasal lavage fluids 10, 60, and 360 minutes after allergen challenge. Results: Pretreatment with intranasal heparin produced a significant reduct ion in symptom score 10 minutes after allergen challenge and reduced the eo sinophil influx at each time point after antigen challenge, statistical sig nificance being reached 60 and 360 minutes after allergen challenge. Simila rly, the amount of eosinophil cationic protein in the nasal wash was reduce d at each time point; this reached statistical significance 360 minutes aft er allergic challenge. Conclusion: Heparin was shown to provide protection with respect to nasal a llergen challenge. The mechanism by which heparin produces its protective a ctivity seems to be related to the neutralization of cosinophil cationic pr otein as well as to the reduction of cosinophil recruitment.