DETERMINATION OF CRYOGLOBULINS AS LIPOPROTEIN-AUTOANTIBODY IMMUNE-COMPLEXES AND ANTIGENIC DETERMINANTS AGAINST ANTILIPOPROTEIN AUTOANTIBODY

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 28  (3) , 437-444
Abstract
Serum Ig[immunoglobulin]G-antilipoprotein-autoantibody activity (at 4.degree. C) of a plane xanthoma patient was shown by double-immunodiffusion method. Cryoglobulins in the serum were dissociated to polyclonal IgG and .alpha.- and .beta.-lipoproteins by acidification and were reconstructed by neutralization. The IgG fraction of the cryoglobulins precipitated with lipoproteins. The cryoglobulins were demonstrated to be immune complexes of polyclonal IgG-antilipoprotein-autoantibody and both .alpha.- and .beta.-lipoproteins. A part of the lipoprotein-autoantibody immune complexes was not cryoprecipitable. Antigenic determinants for the autoantibody existed in the lipid moieties of lipoproteins, in contrast to the apoproteins which determined the specificity to heteroimmune anti-lipoprotein antibody. The presence of more than 9 different antigenic determinants against the autoantibody indicated that lipoproteins were immunologically heterogeneous depending upon the lipid moieties. Lipoproteins reactive with the autoantibody varied quantitatively in normal individuals and were not detected in a primary hyper-.beta.-lipoproteinemia patient and in a primary biliary liver cirrhosis patient with much lipoprotein-X. The absence of antigenicity in the 2 patients'' sera is most likely caused by abnormal lipid moieties of lipoproteins.