Non-macrophage-related accumulation of cholesterol during probucol treatment in familial hypercholesterolemia: report of two cases.

Two patients receiving long-term (3-4 years) treatment with probucol for familial hypercholesterolemia (FH) developed diffuse yellow lesions over the upper eyelids suggesting lipid storage in those tissues (diffuse lipid-storage lesions). Interestingly, each patient had shown a substantial reduction in their cholesterol levels together with a marked regression of their tendon xanthomas or typical xanthelasmas during treatment. To evaluate the role of probucol in this unusual finding we conducted histological and immunochemical evaluations of the lesions (removed surgically) and compared them with those of a non-probucol-treated subject with FH and typical audinal xanthelasma. In both probucol-treated patients the lesions were filled with foam cells and contained large amounts of cholesteryl ester. However, immunochemical analysis of the lesions of one patient using anti-monocyte monoclonal antibody (HAM56) demonstrated that they were not composed of macrophage-derived foam cells in contrast to those of the non-probucol-treated subject which stained clearly with anti-monocyte monoclonal antibody. In each case the foam cells did not react with muscle-actin-specific monoclonal antibody (HHF35). It appears that non-macrophage-related diffuse lipid-storage lesions may occur even during treatment with probucol despite the reduction in cholesterol levels and the regression of xanthomas, suggesting that probucol may alter the distribution of cholesterol from the macrophage to other cells.