[Effect of platelet lysates on the proliferation of human bone marrow cells]

We tested the effect of a lysate from intact human platelets on human granulocyte-macrophage colony forming cells (GM-CFC) using the agar culture technique according to Pike and Robinson. Platelet lysate (PL) was prepared by freeze-thaw procedures of fresh and washed platelets. The results demonstrate the ability of PL to inhibit proliferation of GM-CFC up to about 60-80%. The inhibition is dose-dependent (a hyperbolic curve) and not caused by the influence of PL on CSF-production of feeder layer cells. Direct addition of CSF to the over layer (without feeder layer) maintains the inhibition of colony forming in human bone marrow by PL. The effect of PL may be related to physiological conditions of used platelets. Removal of granulocytes from the experimental system changes the inhibition characteristic of TL in a complex manner. In this case, the inhibition by TL on GM-CFC was found at low concentration only.