Prognostic value of the determination of serum lactic dehydrogenase and its isoenzymes in children with acute lymphoblastic leukaemia.

Serum total lactic dehydrogenase (LDH) levels have been found to be significantly higher in 21 children with acute lymphoblastic leukaemia (ALL) at initial diagnosis than the values of 12 children who achieved remission. The mean value of serum LDH levels in patients with high-risk factors was 2347 +/- 1490 U/ml (range 430-5460 U/ml), while in patients at standard risk it was 652 +/- 385 U/ml (range 110-1320 U/ml). The serum LDH values were above 1320 U/ml in 70% of the 13 children with high-risk factors. The serum isoenzyme patterns were analyzed in 17 of these children at the initial diagnosis. Although LDH-3 and LDH-2 were prominent at the time of diagnosis; LDH-2 and LDH-1 were the predominant isoenzymes in remission. The highest concentrations of LDH-3 were observed in the high-risk group at diagnosis and the ratio of LDH-3 to LDH-2 exceeding 1.0 was found in children who had high-risk factors, but not in any patients in the standard risk group.