Fatty acid composition of lymphocyte membrane phospholipids in children with acute leukemia

The composition of phospholipid fatty acids (PLFA) of separated mononuclear blood cells (MNC) from patients with leukemia was established by high-resolution gas chromatography. Abnormal fatty acid concentrations are detected in the MNC membrane phospholipids in patients with acute lymphoblastic leukemia (ALL) without a deficiency of essential fatty acids (EFA). Significantly reduced relative levels of linoleic acid (4.35 vs. 7.82%; P < 0.001) are found in the MNC-PL in patients with ALL as compared to a healthy control group. Moreover, the Delta (6)-desaturated fatty acids are increased: gamma-linoleic acid (3.56 vs. 0.17%; P < 0.001), arachidonic acid (21.82 vs. 16.27%; P < 0.05), docosatetraenoic acid (3.52 vs. 1.56%; P < 0.001), docosapentaenoic acid (0.34 vs. 0.04% P < 0.001), octadecatetraenoic acid (0.53 vs. 0.23%; P < 0.05), eicosatetraenoic acid (1.83 vs. 0.08%; P < 0.001) and docosahexaenoic acid (2.77 vs. 1.54%; P < 0.001). A increased Delta (6)-desaturase activity is postulated as the cause for the increased level of desaturate products or the increased Delta (6)-activity index (Ratio of gamma-linoleic acid + dihomogamma-linolenic acid to linoleic acid) (1.21 vs. 0.27; P < 0.001). The Delta (6)-enzyme activities measured using linoleic acid and alpha -linoleic acid as substrate underscore these findings (Delta (6) (n-6); 2.49 vs. 0.65 and Delta (6)(n-3); 2.75 vs. 1.12 nmol X h(-1)/10(8) MNC). In contrast, patients with acute myeloid leukemia (AML) do not show any significant differences in the lymphocyte membrane PLFA and no Delta (6)-desaturase abnormalities. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.