Relationship between NK Cell Activity and Glucose Regulation in Type 2 Diabetes Patients

Introduction: NK cells are cytotoxic lymphocytes critical to innate immunity. The purpose of this study is to find out the difference in NK cell activity between type 2 diabetes patients and controls, and to investigate the association between NK cell activity and glucose control. Methods: 49 subjects were enrolled in this study, with 23 type 2 diabetes patients and 26 normal glucose tolerant controls. Anthropometric and biochemical parameters were assessed. Homeostatic model assessment (HOMA) was calculated for insulin resistance. NK cell activity was measured using a newly developed NK Vueⓡ Kit (ATgen, Seoul), which is a method of detecting and comparing interferon-gamma level from NK cells. Results: NK cell activity was lower in type 2 diabetes patients compared to control subjects. There was a significant inverse linear relationship between NK cell activity and fasting plasma glucose after adjusting for age and gender (r = -0.346, P = 0.045). Postprandial glucose and HbA1c showed a similar tendency with NK cell activity (r = -0.313 and -0.241, and P = 0.072 and 0.17, respectively). Regression analysis showed HbA1c, fasting glucose and postprandial glucose to be independent predictors of NK cell activity (beta = -0.303, -0.360, -0.356, and P = 0.034, 0.011, 0.033). There was no relationship between NK cell activity and HOMA-IR. Conclusions: NK cell activity was lower in type 2 diabetes compared to controls, and it was significantly related to degree of hyperglycemia. A further, larger population study is warranted to confirm the possible correlation.