HBsAg-induced hypertrophic smooth endoplasmic reticulum as a target for liver-kidney microsomal (LKM) antibodies.

To test the hypothesis that LKM antibodies are directed against antigen(s) of the smooth endoplasmic reticulum, liver biopsies from patients with HBsAg chronic hepatitis, rich in liver cells with HBsAg-induced hypertrophic SER, were used. A close correspondence was seen between cells with HBsAg-positive cytoplasm by immunoperoxidase and cells with a stronger and more homogeneous fluorescence by indirect immunofluorescence with LKM-positive sera. These results point to antigenic components of SER as reacting with LKM antibodies. The relevance of antigens present in the ribosomes and membranes of rough endoplasmic reticulum needs further evaluation.