Alpha-1-antitrypsin and the liver: a routine immunohistological screen.

One hundred and eighty five consecutive liver biopsies were immunostained using anti-alpha-1-antitrypsin to assess the use of routine immunohistochemistry in the diagnosis of alpha-1-antitrypsin (AAT) deficiency. About half the livers showed staining of hepatocytes for alpha-1-antitrypsin, but most of these livers showed a panlobular pattern, possibly indicating increased synthesis of AAT. Only ten contained periportal granules, said to be typical of AAT deficiency. In cases in which serum was also available for quantitation and phenotyping there was no absolute relation between staining pattern, phenotype, and serum concentrations: the immunohistological screening technique, therefore, has limitations in the diagnosis of AAT deficiency in liver biopsy specimens.