The changes in plasma lipoproteins in a case of heterozygous familial hypercholesterolemia after plasmapheresis.

The changes in plasma lipoproteins after plasmapheresis were estimated in a case of heterozygous familial hypercholesterolemia. Two and a half liters of plasma were exchanged with the same volume of Plasmanate. The effects of cholestyramine on the changes in plasma lipoproteins were also studied after the second plasmapheresis. Fasting plasma was collected serially, and plasma VLDL, IDL, LDL1 (1.019 less than d less than 1.045), LDL2 (1.045 less than d less than 1.063), HDL2 (1.063 less than d less than 1.125) and HDL3 (d greater than 1.125) were separated by ultracentrifugation. The cholesterol and apoprotein contents in these lipoprotein fractions were analyzed. Apoprotein AI, AII, B, CII and E were measured by single radial immunodiffusion. VLDL-C and plasma apoprotein CII and E increased very rapidly. The IDL-C increase was slightly slower than that of VLDL-C. LDL1-C continued to increase for three weeks, but LDL2-C reached a plateau around a week after plasmapheresis and declined thereafter. The change of apoprotein B was similar to that of cholesterol in VLDL, IDL, LDL1 and LDL2. Cholesterol amounts in HDL2 and HDL3 changed in a parallel manner, as did apoprotein AI and AII. HDL2 and HDL3 reached their preplasmapheresis levels in a week. Cholestyramine did not inhibit the increase of VLDL, IDL, LDL1 or LDL2 in this case.