AIM:To investigate the effects of estradiol (E2) and progesterone on the unstimulated and oxidative stressstimulated production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-8, and macrophage chemotactic protein (MCP)-1 by peripheral blood mononuclear cells (PBMCs) from patients with chronic hepatitis C and healthy controls. METHODS:The PBMCs were separated from agematched 72 males and 71 females with and without chronic hepatitis C, who were divided into two groups based on a mean menopausal age of 50 years. Oxidative stress was induced by hydrogen peroxide in the cells incubated in serum-free media. Cytokines in the culture supernatant were measured by an enzyme-linked immunosorbent assay. RESULTS:The highest levels of the spontaneous production of TNF-α, IL-1β, IL-8, and MCP-1 by the unstimulated PBMCs were in the older male patients with chronic hepatitis C and the lowest levels were in the premenopausal female healthy controls. E2 inhibited the cytokine production by the unstimulated PBMCs from the older male and post-menopausal female patients, which was further stimulated by progesterone. The exposure to hydrogen peroxide in the PBMCs from the younger male and pre-menopausal female healthy subjects induced the production of cytokines. The change rates of the hydrogen peroxide-stimulated cytokine production were suppressed by E2 and enhanced by progesterone. CONCLUSION:These findings suggest that E2 may play a favorable role in the course of persistent liver injury by preventing the accumulation of monocytes-macrophages and by inhibiting proinflammatory cytokine production, whereas progesterone may counteract the favorable E2 effects. AIM: To investigate the effects of estradiol (E2) and progesterone on the unstimulated and oxidative stressstimulated production of tumor necrosis factor (TNF) -α, interleukin (IL) -1β, IL-8, and macrophage chemotactic protein (MCP) -1 by peripheral blood mononuclear cells (PBMCs) from patients with chronic hepatitis C and healthy controls. METHODS: The PBMCs were separated from agematched 72 males and 71 females with and without chronic hepatitis C, who were divided into two groups based on a mean menopausal age of 50 years. Oxidative stress was induced by hydrogen peroxide in the cells incubated in serum-free media. Cytokines in the culture supernatant were measured by an enzyme-linked immunosorbent assay. RESULTS: The highest levels of the spontaneous production of TNF- IL-1β, IL-8, and MCP-1 by the unstimulated PBMCs were in the older male patients with chronic hepatitis C and the lowest levels were in the premenopausal female healthy controls. E2 inhibited the cytokine production by the unstimulated PBMCs from the older male and post-menopausal female patients, which was further stimulated by progesterone. The exposure to hydrogen peroxide in the PBMCs from the younger male and pre-menopausal female healthy subjects induced the production of cytokines. The change rates of the hydrogen peroxide-stimulated cytokine production were suppressed by E2 and enhanced by progesterone. CONCLUSION: These findings suggest that E2 may play a favorable role in the course of persistent liver injury by preventing the accumulation of monocytes-macrophages and by inhibiting proinflammatory cytokine production , while progesterone may counteract the favorable E2 effects.