THE SEVERITY OF CLINICAL SYMPTOMS IN RAGWEED-ALLERGIC PATIENTS IS RELATED TO THE EXTENT OF RAGWEED-INDUCED COMPLEMENT ACTIVATION IN THEIR SERA

We have previously reported a correlation between the extent of ragwee d allergen (RWA)-induced in vitro serum complement activation and the symptom scores registered daily during the ragweed (RW)-blooming seaso n in RW-allergic patients. The present study was performed in 22 15-17 -yearold RW-allergic adolescents. Serum samples were incubated with 10 0 mu g/ml RWA, and the generation of different complement activation p roducts was measured by ELISA or RIA. Symptom scores were registered f or 4 weeks during the RW-blooming season. The patients were divided ac cording to the extent (low or high) of the generation of complement ac tivation products, and symptom scores registered in the two groups wer e compared by two-way ANOVA. Significantly higher symptom scores were obtained in the high than in the low complement activation group (P va lues: 0.049 for C1rC1sC1inh, 0.022 for C3bBbP, 0.015 for C5b-9, 0.0001 for C3a, and 0.0008 for C5a). Similar results were obtained at the me asurement performed in the sera obtained from the same patients half a year before the season (P values: 0.022 for C3bBbP, and 0.005 for C5b -9). These findings indicate that complement activation induced by the allergen may enhance the clinical symptoms of RW allergy.