The present invention develops a straightforward and rapid method for generating immunomodulatory cells from peripheral mononuclear cells, comprising treating peripheral mononuclear cells with a hepatocyte growth factor (HGF) to induce differentiation of the peripheral mononuclear cells into immunomodulatory leukocytes. The present invention also provides an immunomodulatory cell prepared according to this method. The present invention further provides a method for treating a disease caused by abnormal immune response comprising administering a HGF to a patient exhibiting the disease, inducing the patient's peripheral mononuclear cells to differentiate into immunomodulatory leukocytes, and modulating the abnormal immune response.
