Profiles and prognostic values of serum LDH isoenzymes in patients with haematopoietic malignancies

Serum lacticodehydrogenase (LDH) is commonly increased in patients with haematopoietic malignancies and has been shown to be a prognostic factor in patients with non-Hodgkin's lymphoma (NHL) and myeloma. We have examined the LDH isoenzyme content in serum of 326 patients, including 252 patients with NHL (202 at diagnosis and 50 at relapse), 28 patients with Hodgkin's disease, 17 patients with CLL, 16 patients with myeloproliferative syndromes and 13 patients with multiple myeloma. Among these, 160 pts (49%) had increased serum LDH. The analysis of LDH isoenzyme profiles in all patients showed increased percentages of isoenzyme 2 in patients with NHL, CLL and myeloproliferative syndromes, but not in samples from patients with myeloma or Hodgkin's disease. Isoenzyme alterations were then analyzed for their prognostic value in patients with NHL. In univariate analyses, increased isoenzyme 2 percentages, increased isoenzyme 3 values, total serum LDH, performance status, stage and tumour aggressiveness were prognostic variables for survival. In a multivariate analysis increased LDH isoenzyme 3 values, high isoenzyme 2 percentages and the performance status, but not total serum LDH, were independent prognostic factor for survival. High isoenzyme 3 values were predictive of early death in NHL patients. In patients with relapsing NHL, the overall survival was 12 months in patients with normal isoenzyme 3 but only 2 months in patients with increased isoenzyme 3 values. We conclude that there are characteristic alterations in serum LDH profiles in patients with haematopoietic malignancies and that some of these may be more interesting in terms of prognostic value than total serum LDH.