Effects of heparin on in vitro immune parameters

The effects of heparin on several in vitro immune functions [blastogenesis, interleukin-2(IL-2) production] were investigated. The addition of heparin to human peripheral mononuclear cells stimulated with phytohemagglutinin or pokeweed mitogen significantly increased the blastogenic response of these cells. Peak IL-2 concentrations in the supernatant of heparin-containing cultures were two- to fourfold higher than in heparin-free cultures. Flow cytometry experiments revealed that Leu-M3-positive cells were the only subset to be significantly affected by heparin, which induced an increase both in number and in fluorescence intensity of Leu-M3-positive cells. In contrast, the expression of DR molecules on monocytes was slightly decreased. It is speculated that the observed antimetastatic effects of heparin may be exerted through local immunomodulation in macrophage-rich tissues.