Serum trypsin inhibitory capacity and pi phenotypes. II. Prevalence of alpha1-antitrypsin deficiency in an allergy population.

A series of 138 patients seen consecutively in an adult allergy clinic were studied to determine serum alpha1-antitrypsin (alpha1-AT) levels and protease inhibitor (Pi) phenotypes. These were compared with a control group of 700 healthy young adult blood donors. Both total serum trypsin inhibitory capacity (STIC) and alpha1-AT levels as determined by immunoelectrophoresis (IEP) were measured. Phenotypes were determined by antigen-antibody-crossed IEP. Alpha1-AT levels in the allergy group were not significantly different from control values. STIC in the allergy group was 1.34 +/- 0.28 mg. trypsin inhibited per ml. serum and in the controls, 1.32 +/- 0.28 mg. IEP values were 205 +/- vs. 200 +/- 36 mg. per dl. Similarly, no increase in Pi phenotypes known to be related to any disease state was observed. Since Pi phenotypes other than the most common MM are rare in Negro populations, phenotype data were corrected to include only Caucasian subjects. In the allergy group adjusted for racial composition we found 2.86% MZ, 5.72% MS; no SZ, SS or ZZ was detected. A comparable control group contained 3.68% MZ, 6.23% MS, 0.71% SZ-SS, but no ZZ Pi phenotype.