Profiles and prognostic values of LDH isoenzymes in patients lymphoma

Serum lactic dehydrogenase (LDH) is an important prognostic factor in patie nts with non-Hodgkin's lymphoma (NHL). We have examined the LDH isoenzyme c ontent in serum and CSF of patients with NHL, at diagnosis and at relapse. In patients with increased serum LDH at diagnosis, the percentage of isoenz yme 2 was increased in 52% of patients and the absolute value of isoenzyme 3 was increased in 64% of patients. In relapsing patients these values were respectively 69% and 65%. Conversely in patients with increased serum LDH due to myeloid regeneration after chemotherapy, isoenzymes 4 and 5, but not isoenzymes 2 or 3, were increased. High absolute values of isoenzyme 3 wer e correlated with an altered performance status, advanced tumor stage, and agressive histology whereas high isoenzyme 2 percentages were correlated wi th altered performance status only. Among patients with high total serum LD H, a high content of isoenzyme 2 and a high absolute value of isoenzyme 3 w ere correlated with high serum revels of TNF alpha and TNF receptor p75. An alysis of total LDH and LDH isoenzyme profiles in CSF did not reveal any co rrelation with meningeal involvement by lymphoma. High isoenzyme 2 percenta ges and high absolute values of isoenzyme 3 in serum were both significantl y associated with a shorter freedom-from-progression and overall survival. Isoenzyme 3 remained a prognostic factor for survival even when considering only patients with high total serum LDH at diagnosis. We conclude that the re are some characteristic serum LDH isoenzyme profiles in patients with NH L and that some of these specific alterations may help refine the prognosti c value of total serum LDH.