Alpha 1-antitrypsin deficiency and PI typing in patients with chronic urticaria.

A group of 281 patients with chronic urticaria was classified into various subtypes and compared with 357 healthy controls for PI types of alpha1-antitrypsin. Total alpha 1-antitrypsin was measured by the Mancini technique, and PI types were determined by isoelectric focusing. The MZ phenotype and the Z gene frequency were significantly more frequent in the urticaria group. The Z gene predominated in the groups with cold urticaria and acquired angio-oedema. The total group of chronic urticaria patients showed a significant decrease in total alpha 1-antitrypsin compared with the control group (P less than 0.03). Deficiencies in alpha 1-antitrypsin may predispose to the development of certain types of urticaria and angio-oedema.