Study of the relationship between the granulocyte LDH, alkaline phosphatase and Zn at the level of the leukocyte in patients with chronic myeloid leukemia.

Mixed leukocyte suspensions were prepared from heparinized blood collected from healthy subjects and from patients with chronic myeloid leukemia (CML). In all the suspensions determinations were made for: zinc, by atomic absorption; granulocyte alkaline phosphatase (GAP), using the method with p-nitrophenylphosphatase; granulocyte LDH, by means of the enzymatic autoanalyser LKD 8,600. In the patients with CML, the values of zinc and of granulocyte alkaline phosphatase activity were very low while the granulocyte LDH values were higher than normal. The chromatogram of the granulocyte LDH isoenzymes on DEAE-Sephadex A50 minicolumn (0.5 X 12 cm) showed an "alpha type abnormality" revealed by the increased activity of the isoenzymes with high electrophoretic mobility LDH2 and LDH1 specific for tissues with intense oxidative phosphorylation. In the normal subjects the chromatogram of the leukocyte LDH isoenzymes showed a type M (skeletal muscle) prevalence denoting intense anaerobic glycolysis. Therefore the low zinc concentrations (0.55 micrograms mg N2 as compared with the normal 1.24 micrograms mg N2) in these patients cause the decrease of GAP activity by the lack of zinc in the active center of the enzyme and the decrease of cellular permeability thus allowing the extracellular release of granulocyte LDH.