Objective: Natural killer T-cells (NKT cells) are believed to play an important role in the regulation of immune response, and a numerical and functional deficit of NKT cells has been reported to be associated with the pathogenesis of autoimmune diseases. Thus far, it has been shown that subjects with type 1 diabetes have a lower frequency of NKT cells than nondiabetic subjects. In this study, we measured the frequency of peripheral Valpha24(+) Vbeta11(+) T-cells, which include human NKT cells, in Japanese diabetic patients.
Research design and methods: Peripheral blood samples were obtained from 164 Japanese diabetic patients and 67 healthy subjects. The diabetic patients were classified into four categories as follows: islet-associated autoantibody-positive (Ab(+)) and -negative (Ab(-)) classic type 1 diabetes, latent autoimmune diabetes in adults (LADA), and type 2 diabetes. We measured the frequency of peripheral Valpha24(+) Vbeta11(+) CD3(+) triple-positive cells.
Results: Unexpectedly, a higher frequency of Valpha24(+) Vbeta11(+) T-cells was observed in Ab(+) and Ab(-) patients compared with LADA patients (P = 0.0294 and P = 0.0021), type 2 diabetic patients (P < 0.0001 and P < 0.0001), and healthy subjects (P = 0.0046 and P = 0.0001). Moreover, an inverse correlation between Valpha24(+) Vbeta11(+) T-cell frequency and disease duration was observed in Ab(+) (rho = -0.455; P = 0.0023) and Ab(-) (rho = -0.432; P = 0.0162) patients.
Conclusions: Our findings indicate that a high frequency of Valpha24(+) Vbeta11(+) T-cells is a unique finding in recent-onset classic type 1 diabetes, and measurement of Valpha24(+) Vbeta11(+) T-cell frequency may be useful to assess the disease activity of classic type 1 diabetes.