WASP VENOM IMMUNOTHERAPY CHANGES IGG ANTIBODY SPECIFICITY

Background The evolution of the IgG response during venom immunotherap y (VIT) has been previously investigated in terms of antibody titres a nd subclasses. Objectives The present work studied the evolution of Ig G antibody fine specificity in wasp allergic patients treated with rus h VIT. Methods Antibody specificity was evaluated in 51 wasp allergic patients in competitive ELISA using streptavidin biotin technology. Pa tients were tested before and during specific rush immunotherapy (at 1 5 days, 6 months, 12 months) and compared with 44 patients treated by venom injections for at least 2 years. Results The capacity of sera to prevent the antigen binding of pooled IgG from allergic patients chan ged rapidly with mean percentage inhibitions (+/- SD) falling from 70 +/- 11-5 1 +/- 18% after 15 days of treatment (P< 0.001 by one way ANO VA). Similarly, the antigen binding capacity of pooled IgG from VIT pa tients was differently prevented by sera with mean percentage inhibiti ons increasing from 37 +/- 12-65 is after 15 days of treatment (P < 0. 0001 by one-way ANOVA). Conclusions 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 o f VIT.