Efficacy of serum lactate dehydrogenase and its isozymes in monitoring the therapy in patients with acute leukemia.

The pretreatment levels of serum Lactate Dehydrogenase (LDH) and its isozymes are measured in 12 cases of Acute Lymphoid Leukemia (ALL) and 8 cases of Acute Myeloid Leukemia (AML) and compared with 14 matched healthy controls. Patients showed only first three bands of LDH while normal sera exhibited five bands. A significant increase in total LDH activity was observed in patients of both the groups as compared to controls at the time of admission. The patients were treated with chemotherapy and were followed at 72 hrs. and after 4 weeks. The patients who successfully responded to the therapy showed increased levels of total LDH and LDH2 and LDH3 isoenzymes as early as 72 hrs. after commencement of the therapy. The nonresponders, on the other hand, circulated, decreased or unaltered values of isozymes during this interval. Following them up for a month, ALL responders showed decreased values of total LDH activity, LDH2 and LDH3 activities when compared with their 72 hour values except LDH1. Non responders of this group had practically unaltered values of these isozymes. AML responders circulated decreased values of all the isozymes while AML non responders "showed significant increases in total LDH, and all its isozymes as compared with their 72 hour values. The determination of total enzyme and its isozyme levels at pre, mid and end of treatment seems to be a promising biochemical parameter to predict the early response to chemotherapy administered.