Deficiencies of Circulating Mucosal-associated Invariant T Cells and Natural Killer T Cells in Patients with Acute Cholecystitis

Mucosal-associated invariant T (MAIT) cells and natural killer T (NKT) cells are known to play crucial roles in a variety of diseases, including autoimmunity, infectious diseases, and cancers. However, little is known about the roles of these invariant T cells in acute cholecystitis. The purposes of this study were to examine the levels of MAIT cells and NKT cells in patients with acute cholecystitis and to investigate potential relationships between clinical parameters and these cell levels. Thirty patients with pathologically proven acute cholecystitis and 47 age- and sex-matched healthy controls were enrolled. Disease grades were classified according to the revised Tokyo guidelines (TG13) for the severity assessment for acute cholecystitis. Levels of MAIT and NKT cells in peripheral blood were measured by flow cytometry. Circulating MAIT and NKT cell numbers were significantly lower in acute cholecystitis patients than in healthy controls, and these deficiencies in MAIT cells and NKT cell numbers were associated with aging in acute cholecystitis patients. Notably, a reduction in NKT cell numbers was found to be associated with severe TG13 grade, death, and high blood urea nitrogen levels. The study shows numerical deficiencies of circulating MAIT and NKT cells and age-related decline of these invariant T cells. In addition, NKT cell deficiency was associated with acute cholecystitis severity and outcome. These findings provide an information regarding the monitoring of these changes in circulating MAIT and NKT cell numbers during the course of acute cholecystitis and predicting prognosis.

Study of natural killer and natural killer T cells in chronic hepatitis C infection

Natural killer [NK] and natural killer T [NKT] cells are components of the innate immune system, and participate in the inflammatory processes during hepatic diseases. Impaired activity of these cells is suggested to contribute to viral persistence and chronic infection in hepatitis C virus [HCV] infection. However, the exact mechanisms are not yet fully understood. To investigate the frequency of peripheral NK and NKT cells in patients with chronic HCV infection, as compared with healthy controls. Thirty patients with chronic hepatitis due to HCV infection were included. Patients with liver cirrhosis, HCV and hepatitis B virus co-infection, diabetes mellitus, or who received interferon therapy were excluded. In addition, 20 normal healthy individuals were included as controls. Assessment of the frequency of peripheral NK and NKT cells by flow cytometry was carried out for all individuals. Compared with controls, patients with HCV had significantly lower percentages of NK and NKT cells in peripheral blood. Among patients with HCV, NK and NKT cell percentages did not correlate significantly with serum transaminase levels. Defective innate immunity, as evidenced by reduced peripheral NK and NKT cell frequency, is observed in patients with chronic hepatitis C infection