Elevated levels of serum vascular endothelial growth factor in patients with polycythaemia vera.

Angiogenesis seems to be a prominent event of myeloproliferative diseases. There are few reported data on angiogenesis and the significance of its stimulator, the vascular endothelial growth factor (VEGF), in polycythaemia vera (PV). We report our observation of elevated serum VEGF levels in patients suffering from PV. Twenty patients with PV and 20 age-matched healthy subjects were enrolled. VEGF levels were measured by a quantitative sandwich enzyme immunoassay. Serum VEGF levels in PV were found to be very significantly higher than in healthy individuals (569.7 +/- 101.2 vs. 164.7 +/- 32.8 pg/ml, p = 0.001). We found no correlation between VEGF and haemoglobin, platelet or leucocyte counts in the patient group. Different therapeutic regimens had no influence on VEGF levels. However, in the control group, we observed a positive correlation between VEGF levels and platelet counts (r = 0.52, p = 0.02). Platelet counts did not differ between patients and healthy subjects. We also evaluated platelet-poor plasma VEGF levels in 10 patients and in all healthy individuals. We found very low levels of VEGF, approximately zero in most cases, in both groups and there was obviously no difference between the two groups. Our results indicate that VEGF is overproduced in PV. However, follow-up studies are needed to verify the role of this factor.