Objective: To investigate lipoprotein lipase (LPL) and serum thymidine kinase (TK) levels in chronic lymphocytic leukemia (CLL) and their correlations with other prognostic factors.
Methods: LPL expression level in peripheral blood samples of 58 CLL patients was detected by semi-quantitative reverse transcription PCR (RT-PCR). Serum TK1 level in 39 CLL patients was detected by enhanced chemiluminescence (ECL) and TK monoclonal antibody (Anti-TK mAb). IgVH mutation status was detected by multiplex PCR and sequencing of purified PCR products. The expression of ZAP-70 protein and CD38 were determined by flow cytometry . Panel probes and fluorescence in situ hybridization (FISH) were used to detect cytogenetic aberrations.
Results: The median LPL expression level in CLL was 0.26 (0 -6.29), while undetectable in normal controls. LPL expression level was significantly correlated with IgVH mutation status, Binet stages, CD38 and cytogenetic aberrations. Patients with unmutated IgVH genes had higher LPL than those with IgVH mutations (P = 0.010). Patients in Binet stage B and C had higher LPL than those in stage A (P = 0.011). LPL level was higher in patients with CD38 > or = 30% (P = 0.001). Higher LPL level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22) than those with favorable cytogenetics (deletion in 13q as the sole abnormality) (P = 0.002). LPL level was not significantly correlated with sex, age, and ZAP-70 protein (P > 0.05). The level of TK1 was higher in CLL patients than that in normal control (P < 0.05). Patients with higher level of absolute lymphocyte count (ALC), lactate dehydrogenase (LDH), unmutated IgVH genes and ZAP-70 had higher levels of TK1 than those with lower level of ALC, LDH, mutated IgVH genes and ZAP-70 (P = 0.018, P = 0.018, P = 0.030 and P = 0.038, respectively). TK1 level had no correlation with sex, age, Binet stages, CD38, and cytogenetic aberrations (P > 0.05).
Conclusions: LPL expression and serum TK1 levels significantly correlate with other CLL prognostic factors and could be predictive markers for IgVH mutation status. LPL and serum TK1 might be applied to the assessment of prognosis in CLL patients.