The herbal medicine Sho-saiko-to improves cytokine production of peripheral blood mononuclear cells in patients with liver cirrhosis

Abstract The herbal medicine Sho-saiko-to has been widely used in Japan as an oral medication in the treatment of viral liver cirrhosis and its clinical efficacy is well established. Sho-saiko-to is believed to generally strengthen the biophylactic functions of the body and improve immunological functions. However, its mode of action has not been fully described. General practitioners in Japan most frequently administer Sho-saiko-to to patients with liver cirrhosis. Physicians empirically know that this drug is useful in improving the general condition of patients with this disorder. Yet, it is not known how Sho-saiko-to works to improve the immunological disorders in liver cirrhosis patients and how it achieves such good clinical results. This study examined in vitro cytokine production capability of the peripheral mononuclear cells obtained from 25 patients with viral liver cirrhosis utilizing pokeweed mitogen stimulation. The in vitro capability of these cells to produce cytokines such as interleukin-β, interleukin-6, and granulocyte-macrophage, colony-stimulating factor, was specifically investigated. To obtain cultures, peripheral blood was collected from patients with viral liver cirrhosis, as well as from healthy volunteers as controls. Cytokine levels with or without pokeweed mitogen were examined via incubation of each sample for 1 to 5 days. To the samples in which pokeweed mitogen was not added, Sho-saiko-to or Sho-seiryu-to solutions were added and incubated. After this culture period, each sample was centrifuged and a supernatant was collected for measurement. As a result, there was no difference in the cultures without pokeweed mitogen: production of interleukin-1β, interleukin-6, and granulocyte-macrophage colony-stimulating factor of patients' cells and cultures of healthy subjects remained the same. However, production of all three cytokines was significantly lower in the patient group than the control in the cultures with pokeweed mitogen. The production of interleukin-1β, interleukin-6, and granulocyte-macrophage colony-stimulating factor, in the cultures containing the control drug Sho-seiryu-to was the same as those in the cultures with only the control medium. However, cytokine production levels in cultures with Sho-saiko-to concentrations 6 μg/ml or higher significantly increased. The findings of this study suggest that Sho-saiko-to's clinical efficacy could be the result of improvement in the immunological mechanism in patients with liver cirrhosis.