Wasp venom immunotherapy changes IgG antibody specificity.

Abstract

The evolution of the IgG response during venom immunotherapy (VIT) has been previously investigated in terms of antibody titres and subclasses. The present work studied the evolution of IgG antibody fine specificity in wasp allergic patients treated with rush VIT. Antibody specificity was evaluated in 51 wasp allergic patients in competitive ELISA using streptavidin biotin technology. Patients were tested before and during specific rush immunotherapy (at 15 days, 6 months, 12 months) and compared with 44 patients treated by venom injections for at least 2 years. The capacity of sera to prevent the antigen binding of pooled IgG from allergic patients changed rapidly with mean percentage inhibitions (+/-SD) falling from 70+/-11-51+/-18% after 15 days of treatment (P<0.001 by one way ANOVA). Similarly, the antigen binding capacity of pooled IgG from VIT patients was differently prevented by sera with mean percentage inhibitions increasing from 37+/-12-65+/-8 after 15 days of treatment (P< 0.0001 by one-way ANOVA). The immunodominance pattern of IgG epitopes recognized on wasp venom antigens by sera from wasp allergic patients changes soon after initiating rush VIT. Further studies will indicate whether, instead of measuring IgG titres, this marked change could be used as the basis of a new test for monitoring the outcome of VIT.