A clinical and fundamental study of Arai antigen -A new abnormal lipoprotein associated with parenchymal liver diseases

A clinical and fundamenta1 study of a new abnormal lipoprotein designated Arai antigen was performed. Arai antigen has a buoyant density of 1.096±0.01g/cm3 in cesium chloride and molecular weight 90±15×104. Arai antigen was spherical in shape and varied in size of the particles between 10 and 50nm in diameter. Arai antigen was detected in 11 of 12 with fulminant hepatitis, 54 of 88 with acute viral hepatitis, 8 of 11 with acute alcoholic hepatitis, 14 of 20 with decompensated liver cirrhosis and 25 of 58 with hepatocellular carcinoma respectively. It was rarely detected in patients with nonhepatic diseases except for the patients who underwent the craniotomy or the celiotomy. The main compositions of the purified Arai antigen were 55.5% protein, 15.5% phospholipid, 11.0% triglycerides, 8.1% unesterified cholesterol and 7.6% esterified cholesterol. The major apolipoproteins of the purified Arai antigen were apoA-1 and apoE. ApoA-II was significantly decreased. The ratio of apoA-1 to apoE was almost 1:1. The appearance of Arai antigen in serum of patients with severe parenchymal liver injury was thought to be due to abnormalities of nascent HDL metabolism by decreased LCAT activity.