Leptin in acute leukaemias: relationship to interleukin-6 and vascular endothelial growth factor

Leptin alone and in combination with other cytokines has a stimulatory effect on proliferation of leukaemic cells. This effect may be due to prevention of apoptosis of progenitor cells or upregulation of specific receptors on leukaemic precursors that make them more responsive to stimuli. This work investigates the relationship between serum leptin level, serum interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in acute leukaemic patients. The relationship to blood cell counts, haemoglobin and response to chemotherapy was also investigated. The study included 25 acute leukaemic male patients [15 acute myeloid leukaemia (AML) and 10 acute lymphoblastic leukaemia (ALL)] and 15 age and sex matched healthy controls. All were subjected to thorough history taking, clinical examination, complete blood picture, hepatic and renal function tests and determination of serum leptin, IL-6 and VEGF levels. In addition, patients were subjected to bone marrow aspiration, cytochemistry and immunophenotyping study and serum leptin assay after chemotherapy. Serum leptin level showed statistically significant elevation only in AML group (p<0.01). This elevation was unrelated to the presence of extramedullary infiltration or response to chemotherapy and correlated only with body mass index (p<0.05). In ALL, the mean serum leptin level was insignificantly different from the controls. In both AML and ALL, there was no significant difference in serum leptin level before and after treatment. Statistically significant elevation of IL-6 and VEGF, uncorrelated with serum leptin level was detected in AML patients when compared with the controls. No correlation was found between serum leptin level and any of the studied haematological parameters. It is concluded that the release of leptin, IL-6 and VEGF may be regulated by different mechanisms leading to diversity in clinical features of the disease.