Effect of prolonged venom immunotherapy on serum venom-specific IgE and IgG.

Serum venom-specific IgE and IgG were monitored in twenty-three patients receiving venom immunotherapy for more than 3 years. Two response patterns of IgE antibody were found. Following initiation of therapy, seven patients had a rise in serum venom-specific IgE, peaking at one year, then decreasing. Sixteen patients had a persistent fall in IgE antibody titres following initiation of therapy. At the end of 3 years, levels of serum venom-specific IgE in both groups were comparable. The presence of atopy may have influenced the rising IgE antibody response. Serum venom-specific IgG either rose or remained elevated if the pretreatment titres were high. After several years of therapy, there was generally a decrease in serum venom-specific IgG.