Ragweed allergy: correlation between skin reactivity and in vitro complement activation.

Recently we have reported on several observations which indicate that allergen-induced complement activation contributes to the development of the symptoms of ragweed allergy. In the present paper a new finding that supports this assumption is summarized. In 48 ragweed-allergic patients individual skin reactivity to ragweed allergen extract (RWA) was assessed using dilution skin prick testing. Sera of these patients were incubated with 20, 100, and 400 U/ml RWA and generation of two complement activation products, alternative pathway C3-convertase (C3bBbP) and terminal pathway activation complex (C5b-9) was measured by ELISA methods. A strong positive correlation (Spearman correlation coefficient r = 0.495, P = 0.0004, and r = 0.454, P = 0.0012, respectively) was found between individual skin reactivity to RWA and C3bBbP generation induced by 20 and 100 A allergological units/ml (U/ml) RWA. This finding further supports the role of complement activation products in the aggravation of the basic IgE-mediated immunopathology of ragweed allergy.