RESUMEN
To establish the value of serum lactate dehydeogenase [LDH] and alpha hydroxybutyrate dehydrogenase [HBDH] in reflecting the responsiveness of adult a cute lymphoblastic leukaemia [ALL] to the given chemotherapy. Serial measurements of LDH and HBDH in sera of six patients with ALL throughout different phases of therapy [induction, consolidation, maintenance]. Initially high levels of both enzymes were detected in all patients upon presentation. Successful remission induction was associated with normalization of activities of both enzymen in five of six patients. Refractoriness to standard protocol in the remaining patient was accompanied by persistence of high levels of LDH and HBDH. Reappearance of blast cells in circulation was paralleled by elevation of enzyme levels which could be brought again to normal by effective disease control and further chemotherapy. Continuous monitoring of LDH and HBDH is recommended to reflect the disease status and the responsiveness to chemotherapy in ALL