Proportion of natural killer cells in peripheral blood lymphocytes is correlated with cytokine levels in patients with type 2 diabetes mellitus and prediabetes: a preliminary report.

Aims: Natural killer (NK) cells are important innate cytotoxic lymphocytes and can contribute to the immune response through the synthesis and secrete proinflammatory cytokines. In the present study, we assessed and compared the proportion of NK cells in peripheral blood lymphocytes, various cytokine levels and metabolic parameters in type 2 diabetes mellitus (T2DM), prediabetes and normal glucose tolerance (NGT). Methods: Individuals with 57 T2DM, 58 prediabetes and 60 NGT were enrolled. Fasting plasma glucose, 2-h postload glucose, fructosamine, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein and triglyceride levels were assessed on an automatic biochemical analyzer. Various cytokine levels in the serum including IL-2, IL-5, IL-6, IL-10, IL-12p70, and IFN-γ were assessed using ELISA kits. Proportion of NK cells in peripheral blood lymphocytes was assessed by flow cytometry. Results: The proportion of NK in lymphocytes from prediabetes was significantly increased compared with that obtained from T2DM, while the data was significantly decreased compared with that obtained from NGT. Significant increases in fasting plasma glucose, postprandial plasma glucose and triglycerides were observed in prediabetes compared with NGT.IL-12p70 level was significantly lower in prediabetes and T2DM compared with NGT. IL-6 and IFN-γ levels in prediabetes were significantly lower than those in NGT and T2DM patients, in addition IL-6 level in T2DM patients was significantly higher compared to NGT. The trend of IL-10 level was opposite to that of IL-6. Conclusions: The decreased proportion of NK cells in peripheral blood lymphocytes following some cytokine levels (IL-12p70, IL-6,IL-10 and IFN-γ) was likely involved in the development of T2DM and prediabetes. [ABSTRACT FROM AUTHOR]