Cysteinyl leukotriene production in anaphylactic reactions

Anaphylactic reactions are systemic, potentially life-threatening allergic reactions. In several animal models, evidence has been presented that leukotrienes may be of major pathophysiological significance. The aim of the present study was to obtain information on cysteinyl leukotriene production in anaphylactic reactions in humans in vivo. Urinary leukotriene E4 plus N-acetyl leukotriene E4 were determined in nine patients during clinically apparent anaphylaxis and 2-11 days later following recovery. The concentrations of these established parameters of endogenous leukotriene production were strongly enhanced in urine sampled during or shortly after the anaphylactic reaction; they declined to normal or were slightly elevated subsequently. In one patient suffering from exercise-induced anaphylaxis, leukotriene production was provoked together with clinical symptoms by moderate exercise on a bicycle ergometer. Our data provide the first direct evidence that leukotrienes may be involved in anaphylactic reactions in humans in vivo.