Augmenter of liver regeneration (ALR) may promote liver regeneration by reducing natural killer (NK) cell activity in human liver diseases

Cytotoxicity of liver natural killer cells against regenerating hepatocytes has been reported as a possible mechanism of regeneration failure in fulmi nant hepatitis. An augmenter of liver regeneration (ALR) inhibits liver nat ural killer cell activity in rats. In this study, we measured hepatic expre ssion of ALR mRNA, blood levels of ALR, and peripheral blood natural killer cell activity in patients with various types of acute liver disease to inv estigate the relationship between failure of liver regeneration and hepatic natural killer cells. Hepatic ALR mRNA expression was higher in liver dise ase patients than in non-liver disease controls, and a correlation was foun d between serum ALR values and hepatic levels of ALR mRNA. In acute liver i njury? the serum ALR level also showed a negative correlation with NK activ ity. ALR was produced by and released from the liver at the time of hepatic injury. Our findings suggest that ALR may protect against failure of regen eration by inhibition of hepatic natural killer cell activity in acute live r injury.