Platelet enzyme abnormalities in leukemias

The aim of this study was to evaluate platelet enzyme activity in cases of leukemia.

Platelet enzymes glucose-6-phosphate dehydrogenase (G6PD), pyruvate kinase (PK) and hexokinase (HK) were studied in 47 patients of acute and chronic leukemia patients, 16 patients with acute myeloid leukemia (AML)(13 relapse, three in remission), 12 patients with acute lymphocytic leukemia (ALL) (five in relapse, seven in remission), 19 patients with chronic myeloid leukemia (CML).

The platelet G6PD activity was significantly low in cases of AML, ALL and also in CML. G6PD activity was normalized during AML remission. G6PD activity, although persistently low during ALL remission, increased significantly to near-normal during remission (P < 0.05) as compared with relapse (P < 0.01). Platelet PK activity was high during AML relapse (P < 0.05), which was normalized during remission. Platelet HK however was found to be decreased during all remission (P < 0.05). There was a significant positive correlation between G6PD and PK in cases of AML (P < 0.001) but not in ALL and CML. G6PD activity did not correlate with HK activity in any of the leukemic groups. A significant positive correlation was however seen between PK and HK activity in cases of ALL remission (P < 0.01) and CML (P < 0.05).

Both red cell and platelet enzymes were studied in 36 leukemic patients and there was no statistically significant correlation between red cell and platelet enzymes. Platelet enzyme defect in leukemias suggests the inherent abnormality in megakaryopoiesis and would explain the functional platelet defects in leukemias.