Lactate dehydrogenase isoenzymes in patients with essential thrombocythemia.

Various abnormalities have been described in platelets of patients with Essential Thrombocythemia (ET), including alteration in the glycolytic pathway and increased lactate production. Lactate dehydrogenase (LDH) isoenzymes were studied in 15 of these patients. Relative activity of LDH-5 isoenzyme was higher comparing with normal platelets (p < 0.05), while LDH-3 activity was diminished (p < 0.05). LDH-1, LDH-2 and LDH-4 isoenzymes were unchanged. We also found an altered profile of LDH isoenzymes in serum. These findings can contribute to improve the knowledge of platelet defects in ET and be useful in the diagnosis of these patients.