Predictive value of serum IgE levels during rush hyposensitization.

Thirty children with hay fever were studied with in vivo and in vitro tests during rush hyposensitization with Timothy pollen. Clinical assessment was made with the aid of diaries during one season before, and three seasons after, the start of the immunotherapy. When the serum level of IgE increased more than 10% during the first week of the therapy, symptoms were mostly alleviated during the following seasons. An alleviation was rarely found in children with decreasing or unchanged serum IgE levels. No predictive information as to the clinical effect of the immunotherapy was obtained from skin or provocation tests, nor from Timothy-specific antibodies of the IgG or IgE classes. It is proposed that serum IgE determinations should be performed before, and 1 week after, the start of rush hyposensitization in order to find probable therapeutic failures.