Park et al recently reported that proinflammatory cytokines IL-6 and TNFα are important for the progression from hepatic steatosis to steatohepatitis in obese mice and that absence of either IL-6 or TNFR1 reduced lipid accumulation in the liver and also reduced influx of macrophages and neutrophils in livers of mice fed a high fat diet [9]. This evidence concerns the gene TNFRSF1A and fatty liver disease.