TREATMENT OF ANAPHYLACTIC SENSITIVITY TO PEANUTS BY IMMUNOTHERAPY WITH INJECTIONS OF AQUEOUS PEANUT EXTRACT

Background: Immediate hypersensitivity to peanuts is a frequent cause of anaphylactic reactions and deaths in children and adults, Currently , preventive treatment consists of avoidance, which is difficult becau se of the widespread and often disguised use of peanuts in the food in dustry. Methods: Twelve patients with immediate hypersensitivity to in gestion of peanuts were recruited. Half were treated with injections o f peanut extract: a maintenance level of tolerance was first achieved by a rush protocol, then maintained with weekly injections for at leas t 1 year. The other six evert untreated control subjects. Ail patients underwent double-blind, placebo-controlled, oral peanut challenges in itially, after approximately 6 weeks, and after 1 year. Results: All t reated patients achieved the maintenance dose of 0.5 ml of 1:100 wt/vo l peanut extract by the rush injection protocol. All experienced incre ased tolerance to double-blind, placebo-controlled peanut challenge an d decreased sensitivity on titrated skin prick testing with peanut ext ract, whereas the threshold to oral peanut challenge and cutaneous rea ctivity to peanut extract sere unchanged in the untreated control subj ects. Systemic reactions were common in the treated group both during rush immunotherapy and with maintenance injections. Only three patient s remained tolerant of the full maintenance dose. The increased tolera nce to oral peanut challenge was maintained in the three subjects who received full maintenance doses, but there was partial (n = 2) or comp lete (n = 1) loss of protection in the patients who required dose redu ction because of systemic reactions. Conclusions: Injections of peanut extract increase the tolerance of patients with peanut allergy to ora l ingestion of peanuts. Injections result in repeated systemic reactio ns in most patients, even during maintenance injections. For clinical application of this method of treatment, a modified peanut extract is needed.