TNF-alpha induces changes in LDH isotype profile following triggering of apoptosis in PBL of non-Hodgkin's lymphomas.

Based on the possibility of tumor necrosis factor (TNF)-alpha to perform multiple and opposite biologic effects, we simultaneously investigated in vitro its effects on intracellular lactate dehydrogenase (LDH)-H and LDH-M isoenzyme activity and morphological characteristics following induction of apoptosis in peripheral blood mononuclear cells (PBMC) of non-Hodgkin's lymphoma patients (NHL) prior to and after the end of applied chemotherapy. TNF-alpha showed a significant increase ( p<0.05) of LDH-H and LDH-M activity in sonified PBMC of healthy controls after 18 h cultures accompanied with an increase of apoptotic index (AI) from 2.3 to 16.2%. Contrary to this, in PBMC of NHL patients prior to therapy TNF-alpha induced a significant decrease ( p<0.05) of LDH-H isotype activity. In patients after administration of chemotherapy, TNF-alpha in a dose of 100 U/ml induced a significant increase ( p<0.05) of LDH-M isotype activity, but not of LDH-H. In the PBMC of NHL patients prior to chemotherapy, TNF-alpha in vitro induced an increase of AI from 2.8 up to 6.8%, while in PBMC of NHL patients after applied chemotherapy AI changed from 7.2 to 14.4%. However, there was no significant difference in the increase of apoptosis in PBMC of NHL patients with high-grade malignancy and high rate response among patients who received first-line therapy, high-dose therapy, or third-line therapy regimens after in vitro TNF-alpha treatment. These results indicated different susceptibilities of PBMC of NHL to TNF-alpha when effects were analyzed by determination of intracellular LDH isotype profile and induction of apoptosis prior to and after administration of therapy in comparison to effects on healthy controls PBMC.