Letters To The Editor
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jan 21, 2008; 14(3): 487-488
Published online Jan 21, 2008. doi: 10.3748/wjg.14.487
Natural killer T cells and non-alcoholic fatty liver disease: Fat chews on the immune system
Michael Kremer, Ian N Hines
Michael Kremer, Department of Surgery, University of Heidelberg, Heidelberg 69120, Germany
Ian N Hines, Department of Medicine, University of North Carolina at Chapel Hill, CB 7525, United States
Correspondence to: Michael Kremer, MD, Department of Surgery, Mail Box # B5, University of Heidelberg, Heidelberg 69120, Germany. michael_kremer@med.unc.edu
Telephone: +49-6221-5639494
Fax: +49-6221-565450
Received: September 13, 2007
Revised: October 23, 2007
Published online: January 21, 2008
Abstract

Natural killer T cells (NKT) are an important subset of T lymphocytes. They are unique in their ability to produce both T helper 1 and T helper 2 associated cytokines, thus being capable of steering the immune system into either inflammation or tolerance. Disruption of NKT cell numbers or function results in severe deficits in immune surveillance against pathogens and tumor cells. Growing experimental evidence suggests that hepatosteatosis may reduce resident hepatic as well as peripheral NKT cells. Those models of hepatosteatosis and the change in NKT cell numbers are associated with a disruption of cytokine homeostasis, resulting in a more pronounced release of proinflammatory cytokines which renders the steatotic liver highly susceptible to secondary insults. In this letter to the editor, we focus on recently published data in the World Journal of Gastroenterology by Xu and colleagues demonstrating reduced peripheral NKT cells in patients with non-alcoholic fatty liver disease, compare those findings with ours and others in different animal models of hepatosteatosis, and hypothesize about the potential underlying mechanism.

Keywords: Obesity; Hepatosteatosis; Metabolic syndrome