Serum alpha 1-protease inhibitor levels in patients with chronic idiopathic urticaria. 
A comparative study of serum alpha 1-protease inhibitor levels in patients with chronic idiopathic urticaria and control subjects revealed that the values in the patients were significantly lower than those in the controls, especially in patients over 60 years.  The results suggests that some protease which can be inhibited by alpha 1-protease inhibitor may be involved in urticarial reactions in patients with chronic idiopathic urticaria.