Enzyme activation and inhibition induced by cold provocation in a patient with cold urticaria.

A 33-year-old female patient with acquired cold urticaria, together with her 8-year-old healthy daughter, was subjected to a brief period of cold exposure. The effect of this treatment upon a number of key factors of the plasma coagulation, kallikrein and complement systems was investigated. Cold air provocation caused increased fibrinolysis, together with a measurable consumption of the protease inhibitors alpha1-antitrypsin (alpha1AT), alpha2-macroglobulin (alpha2M) and C1Inactivator (C1INA). Kaolin activation of the patient's plasma elaborated exceptionally high levels of esterolytic activity, both before and after cold exposure, indicating pre-enzyme lability. Both subjects had abnormally high serum ratios alpha2M/alpha AT. Impressive leucocytosis was observed in the symptomless child.