Occurrence of an abnormal lipoprotein in patients with liver disease.

An abnormal lipoprotein, containing a high proportion of unesterified cholesterol and phospholipid, has previously been described as occurring in the serum of patients with obstructive jaundice, and has been called lipoprotein X. Using an immunoelectrophoretic method for the detection of lipoprotein X in serum, the sera of 97 patients with liver disease have been screened and the associated biochemical features measured.Lipoprotein X was found in 45% of cases of liver disease with cholestatic features, and was not detected in cases of liver disease without cholestasis. The incidence of lipoprotein X in different causes of cholestatis varied, and while it was commonest in cases of extrahepatic obstruction of recent onset, occurring in 75% of cases, it was also found in primary biliary cirrhosis in 48% of cases, and in cholestatic hepatitis, less commonly.The cause of the appearance of lipoprotein X is unknown, but analysis of associated biochemical features suggested a relationship to physical biliary obstruction rather than a derangement of liver cell function.