Sialic acid and fatty acid concentrations in lymphocytes, red blood cells and plasma from patients with multiple sclerosis

Lipids and constituents of lipids were isolated from peripheral blood lymphocytes (PBL), red blood cells (RBC), plasma and sera from 51 patients with multiple sclerosis (MS) and 51 controls, matched for age, sex and race. The amount of sialic acid released by incubation of intact PBL from MS patients was significantly lower (P less than 0.02) than that of the sialic acid from control lymphocytes. The amounts of sialic acid released by neuraminidase from intact RBC, on the other hand, did not differ significantly between the MS group and the control group. The concentrations of ganglioside sialic acid in PBL from MS and control groups did not vary significantly. Similarly the concentration of ganglioside sialic acid in RBC from MS patients was not significantly different from that in the controls. Analyses of the fatty acids isolated after alkaline methanolysis of the lipids from the PBL of MS patients and controls showed a small but significant decrease (P less than 0.01) in the relative percentage of linoleic acid in patients with MS. Determination of the ester-linked fatty acids in RBC lipids from patients with MS showed a significant decrease (P less than 0.001) in the relative percentage of linoleic acid and an increase (P less than 0.01) in palmitic plus palmitoleic acids compared to control values. The fatty acid composition of the plasma neutral lipids plus free fatty acids showed a very significant decrease (P much less than 0.001) in the relative percentage of linoleic acid, a small decrease (P less than 0.05) in arachidonic acid and significant increases in palmitic (P less than 0.001) and oleic acids (P less than 0.001) in MS, compared to controls. These results are suggestive of possible differences in metabolism of lipids between patients with MS and controls.