The ultrastructural localization of
IgA,
IgA1, and
IgA2 deposited on liver tissues from 13 patients with
alcoholic liver disease and 9 patients with nonalcoholic
liver diseases was investigated by the immunoperoxidase method. A continuous pattern of
IgA deposition along the perisinusoidal area was observed not only in the alcoholic patients but also in the nonalcoholic patients. Ultrastructurally,
IgA deposits were seen on the plasma membranes of Kupffer cells, endothelial cells, and hepatocytes and in the endocytotic vesicles and phagosomes of Kupffer cells and endothelial cells. In the alcoholic group, deposits of
IgA on
collagen fibers were observed at sites where pericellular
fibrosis developed but, on the other hand,
IgA deposits were diminished or absent on the plasma membranes of hepatocytes.
IgA1 showed the same deposit pattern as
IgA.
IgA2 was observed on and in Kupffer cells and endothelial cells but was not detected on the plasma membranes of hepatocytes. From these studies, the authors conclude that
IgA deposition in the liver is not specific for
alcoholic liver disease but may reflect the reduced metabolism of damaged liver. An additional finding was that, of the
IgA subclasses, only
IgA1 combined with the plasma membranes of hepatocytes.