Frequency and significance of phenotypes for alpha1-antitrypsin deficiency in type 1 autoimmune hepatitis.

To evaluate the frequency and significance of alpha1-antitrypsin deficiency in type 1 autoimmune hepatitis, 181 Caucasian patients were assessed for variant phenotypes. Three hundred three Caucasian patients with various other chronic liver diseases were similarly evaluated. Twenty-one of the 181 patients (12%) had heterozygous deficiencies, including the MS (6%) and MZ (6%) phenotypes. These patients were indistinguishable from those with normal phenotypes. Immediate outcomes after corticosteroid therapy were also similar in both groups. Variant phenotypes were present in 34 of the 303 patients with other chronic liver diseases (11%). Patients with nonalcoholic steatohepatitis had a significantly greater frequency of deficiency phenotypes than patients with chronic hepatitis C (20% vs 7%, P = 0.03). In conclusion, deficiency phenotypes are common in type 1 autoimmune hepatitis and they have no clinical or prognostic importance. In certain liver diseases, such as nonalcoholic steatohepatitis, variant phenotypes may be comorbid factors.