Bone marrow and peripheral blood leptin levels in lymphoproliferative diseases - relation to the bone marrow fat and infiltration

Leptin is a nonglycosylated protein produced mostly by adipocytes. The role of leptin in body weight regulation through its anorectic effect in hypoth alamus is very well known. Less known are other leptin effects such as the stimulation of hematopoesis and some parts of immunity system. The role of leptin in the pathogenesis of some malignant tumors is discussed. Only a li ttle is known about bone marl ow adipocyte leptin production. We examined leptin concentrations in the sera from peripheral blood and bon e marrow, the percentage of bone marrow fat, the degree of bone marrow infi ltration, the body mass index (BMT) in 42 patients with lymphoproliferative diseases. We found that bone marrow has significantly lower leptin levels (6,6 +/- 10,9 ng/ml) than peripheral blood (9,1 +/- 11,5 ng/ml) (p < 0.0001 ). Bone marrow and peripheral blood leptin levels have also a significant t hin correlation (r = +0.91, p < 0.0001). Bone marrow (r = +0.55, p < 0.0005 ) and peripheral blood (r = +0.52, p < 0.0005) leptin concentrations are si gnificantly correlated to BMI. Blood serum leptin (r = +0.46, p < 0.003) an d bone marrow leptin (r = +0.40, p < 0.01) are related to the bone marrow f at percentage. In addition we found a negative correlation of blood serum l eptin (r = -0.59, p < 0.0001) and bone marrow leptin (r = -0.42, p < 0.005) to bone marrow malignant infiltration. When we divided the patients into g roups with bone marrow infiltration more than 10% and without or less than 10% infiltration, the first group had significantly lower peripheral blood (p < 0.001) and bone mal row (p < 0.02) leptin. We also confirmed a relatio n of bone marrow fat and infiltration (r = +0.49, p < 0.001). Our results suggest a relationship among leptin levels in blood or bone mal row and bone marrow infiltration in lymphoproliferative diseases. This fac t needs further investigation and an evaluation of its application in clini cal practice.