The role of leucocytes in the acetyl salicylic acid (aspirin) induced nitric oxide synthesis in the production of interferon-alpha, a potent inhibitor of platelet aggregation and a thrombolytic agent.

The role of aspirin-induced NO synthesis in the production of interferon-alpha (IFN-alpha) in leucocytes and the effect of IFN-alpha on platelet aggregation was studied. Treatment of Platelet Rich Plasma (PRP) with the dialyzed supernatant from the leucocyte suspension incubated with 80 microM aspirin resulted in parallel syntheses of NO and IFN-alpha as determined by methemoglobin assay and enzyme linked immunosorbent assay respectively. Incubation of PRP with 10 nM purified IFN-alpha for 40 min resulted in the maximal inhibition of platelet aggregation through the synthesis of NO due to the activation of nitric oxide synthase in platelets by IFN-alpha. The treatment of clotted PRP with IFN-alpha resulted in the lysis of the clot due to the fibrinolysis. Injection of IFN-alpha was found to protect mice from death due to the lysis of ADP-induced coronary thrombus. Interferon-alpha was found to be a potent inhibitor of platelet aggregation and a thromboprotective agent.