[Normolipemic plane xanthomas and IgGk myeloma with anti-lipoprotein activity. Apropos of a case. Review of the literature].

Clinicopathologic findings are reported of a woman with plane xanthomatosis, multiple myeloma (IgG kappa) and normolipemia. Plasma lipoproteins were bound to the monoclonal immunoglobulin. The complex was separated by ultracentrifugation, then the proteins were measured by radial immunodiffusion and laser immunonephelometry. Monoclonal IgG kappa interact with the low-density lipoproteins. The literature about the association between normolipemic or hyperlipemic xanthomatosis and myeloma was reviewed and the physiopathology of this association discussed. Several hypotheses are suggested but, at present, it is shown that lipoprotein-paraprotein complexing in some patients may be due to autoantibody activity of the myeloma protein against serum lipoprotein; immune complexes interfere with normal lipoprotein catabolism resulting in xanthomas and normolipemia or hyperlipemia.