Complement activation in the nasal mucosa following nasal ragweed-allergenchallenge

The aim of this study was to explore complement activation in the nasal lav age following a nasal ragweed-allergen challenge. The study was carried out with 15 adolescents who were allergic to ragweed and with six non-allergic healthy volunteers. Following the baseline measurement after the symptoms were registered, subjects were given increasing doses of ragweed allergen. Lavage fluid was collected and tested for a complement-activation product ( C3bBbP). The allergic patients responded to allergen provocation with an in crease in C3bBbP formation compared to the initial lavage (p = 0.001). The C3bBbP level remained low in the lavage fluids of the non-allergic controls . We found a strong correlation between the threshold dose that induced sym ptoms and the dose where the maximum complement activation was detected (r = 0.78, p = 0.001). Our findings indicate that in allergic patients nasal c hallenge with ragweed allergen induces a rise in complement activation in t he nasal lavage fluid. These results highlight the role of the complement s ystem in the allergic inflammation on the nasal mucosal surface.