Type 3 cytokines in liver fibrosis and liver cancer.

The type 3 cytokines IL-17 and IL-22 play a crucial, well synchronized physiological role in wound healing and repairing tissue damage due to infections or injury at barrier surfaces. These cytokines act on epithelial cells to induce secretion of early immune mediators, recruitment of inflammatory cells to the site of injury, and to trigger tissue repair mechanisms. However, if the damage persists or if these cytokines are dysregulated, then they contribute to a number of inflammatory pathologies, autoimmune conditions and cancer. The liver is a multifunctional organ that plays an essential role in metabolism, detoxification, and immune surveillance. It is also exposed to a variety of pathogens, toxins and injuries. Over the past decade, IL-17 and IL-22 have been implicated in various aspects of liver inflammation. IL-17 is upregulated in chronic liver injury and associated with liver disease progression. In contrast, IL-22 was shown to be hepatoprotective during acute liver injury but exhibited inflammatory effects in other models. Furthermore, IL-22 and IL-17 are both associated with poor prognosis in liver cancer. Finally, the regulatory mechanisms governing the physiological versus the pathological role of these two cytokines during acute and chronic liver injury remain poorly understood. In this review, we will summarize the current state of knowledge about IL-17 and IL-22 in wound healing during acute and chronic liver injury, their contribution to pathogenesis, their regulation, and their role in the transition from advanced liver disease to liver cancer.

Fatal reactivation of hepatitis B virus following cytotoxic chemotherapy for acute myelogenous leukemia: fibrosing cholestatic hepatitis.

Hepatitis B virus (HBV) is a well known pathogen that sometimes causes fulminant hepatitis in patients undergoing cytotoxic chemotherapy. Fibrosing cholestatic hepatitis (FCH) is a recently recognized unique variant of viral hepatitis, which has been occasionally reported in HBV-infected recipients of liver, renal, or bone marrow transplantation. We present here a 48-yr-old male in whom HBV was reactivated during post-remission chemotherapy for acute myelogenous leukemia, which resulted in rapidly fatal outcome. He manifested with deterioration of liver function in association with enormous replication of HBV. Liver biopsy showed marked ballooning of hepatocytes, cholestasis, and periportal fibrosis with minimum infiltrates. Immunostaining revealed that hepatocytes were strongly positive for hepatitis B surface antigen. Under the diagnosis of FCH, he was treated with lamivudine and interferon beta, which was not effective. Autopsy showed severe atrophy of the liver and marked degeneration of hepatocytes. Hematologists should be aware that FCH is a fatal complication that can develop under post-chemotherapy immunosuppressed conditions. Although there is no convincing evidence, prophylactic administration of lamivudine seems to be a reasonable strategy.