Glutamate dehydrogenase activity in lymphocytes of B-cell chronic lymphocytic leukaemia patients.

Objectives: To investigate the pattern of glutamate dehydrogenase (GLDH) activity, GLUD1 and GLUD2 expressions in peripheral blood mononuclear cells (PBMC) of untreated B-chronic lymphocytic leukemia (B-CLL) in healthy individuals (HI) and patients with infectious mononucleosis (IM).
Design and Methods: GLDH activity was determined in a supernatant obtained from pelleted PBMC. GLUD1 and GLUD2 mRNA expression was determined using a quantitative real-time polymerase chain reaction. CD19(+) B cells from PBMC were purified by using positive selection.
Results: The highest GLDH activity was found in PBMC of the B-CLL group followed by the HI group and IM group. The PBMC GLDH activity was higher in 60% of the B-CLL patients according to the established reference interval for our HI (2.17-5.70 microkat/g protein). The greater GLDH activity was also found in the CD19(+) cell preparation of the B-CLL patients (two of the three) but not in HI (n=3). The median value of GLUD1 expression was highest in the IM group (n=11), followed by the HI (n=14) and B-CLL groups (n=59) (median 4.69/3.78, P<0.005 and 4.69/2.91, P<0.0005, respectively). GLUD2 expression was not significantly different between groups.
Conclusions: The increased GLDH activity is specific for the PBMC of B-CLL patients. The GLUD1 but not the GLUD2 gene expression pattern is different between the PBMC of IM and B-CLL patients.