Intrahepatic synthesis of immunoglobulin in liver disease.

Patterns of intrahepatic immunoglobulin production were investigated by an in vitro biosynthetic labelling technique which measured the rate of Ig production in liver biopsy fragments. This technique depends on the incorporation of 3H-leucine into proteins synthesized by cells in the biopsy fragment and subsequently released into the culture medium, and precipitation of Ig with monospecific antisera. Intrahepatic Ig production was expressed as counts of radioactivity precipitated/g of liver tissue/24 h. Mean values were high in various inflammatory diseases of the liver, including alcoholic hepatitis (AH) (17 cases), IgG, 87.8, IgA, 105.6 and IgM, 14.7, chronic active hepatitis (CAH) (19 cases), IgG, 86.0, IgA, 56.1 and IgM, 12.6, and acute viral hepatitis (3 cases), IgG, 116.0, IgA, 61.0 and IgM, 32.0, but low in histologically normal livers (6 cases), IgG, 4.5, IgA, 4.8 and IgM, 4.7, alcoholic fatty liver (11 cases), IgG, 9.4, IgA, 11.4 and IgM, 7.1, and miscellaneous non-inflammatory conditions (10 cases), IgG, 8.7, IgA, 11.1 and IgM, 5.0. Photomicrographs were used to measure the density of plasma cells, expressed as cells/mm2 of liver biopsy tissue: mean counts were for AH 5.1, CAH 16.2 and normal liver 0.0. Intrahepatic Ig production in vitro did not correlate with the density of plasma cells in biopsy samples from cases of AH or CAH, nor with serum Ig levels.