Cytokine profile and lymphocyte subsets in type 2 diabetes

Type 2 diabetes mellitus (T2D) is a metabolic disease with inflammation as an important pathogenic background. However, the pattern of immune cell subsets and the cytokine profile associated with development of T2D are unclear. The objective of this study was to evaluate different components of the immune system in T2D patients' peripheral blood by quantifying the frequency of lymphocyte subsets and intracellular pro- and anti-inflammatory cytokine production by T cells. Clinical data and blood samples were collected from 22 men (51.6±6.3 years old) with T2D and 20 nonsmoking men (49.4±7.6 years old) who were matched for age and sex as control subjects. Glycated hemoglobin, high-sensitivity C-reactive protein concentrations, and the lipid profile were measured by a commercially available automated system. Frequencies of lymphocyte subsets in peripheral blood and intracellular production of interleukin (IL)-4, IL-10, IL-17, tumor necrosis factor-α, and interferon-γ cytokines by CD3(+) T cells were assessed by flow cytometry. No differences were observed in the frequency of CD19(+) B cells, CD3(+)CD8(+) and CD3(+)CD4(+) T cells, CD16(+)56(+) NK cells, and CD4(+)CD25(+)Foxp3(+) T regulatory cells in patients with T2D compared with controls. The numbers of IL-10- and IL-17-producing CD3(+) T cells were significantly higher in patients with T2D than in controls (P<0.05). The frequency of interferon-γ-producing CD3(+) T cells was positively correlated with body mass index (r=0.59; P=0.01). In conclusion, this study shows increased numbers of circulating IL-10- and IL-17-producing CD3(+) T cells in patients with T2D, suggesting that these cytokines are involved in the immune pathology of this disease.