Correlations between circulating plasmacytoid dendritic cells and immune cells in patients with type 1 diabetes mellitus

Objective To explore the correlations between circulating plasmacytoid dendritic cells (pDCs) and other immune cells, clinical parameters in patients with type 1 diabetes mellitus (T1DM), and to investigate the role of pDCs in the pathogenesis of T1DM. Methods A total of 62 patients with T1DM who visited endocrinology at the First Affiliated Hospital of Nanjing Medical University from December 2015 to June 2017 were recruited as study group. A total of 74 age and gender matched healthy volunteers were as the control group. Clinical parameters of all subjects including age, sex, duration of diabetes and HbA1c were recorded. The proportions of circulating pDCs and other immune cells [CD3+, CD4+, CD8+, CD4+ interferonγ+ (IFN-γ+), CD4+ tumor necrosis factor α+(TNF-α+), CD4+ interleukin 4+ (IL-4+), CD4+IL-17+/CD4+ CD25+ Foxp3+ T cells/CD19+/CD19+ CD24hi CD38hi B cells] were detected by flow cytometry. Pearson correlation analysis was performed to explore the correlation. Results The differences in the proportions of pDCs between T1DM patients and healthy controls were statistically significant [(0.21±0.13)% vs (0.28±0.14) %, P=0.006]. Pearson correlation analysis showed that the frequency of circulating pDCs were negatively correlated with the frequency of CD4+IFN-γ+ and CD4+TNF-α+ T cells (r=-0.260, 0.473, respectively, both P<0.05), and positively correlated with the frequency of CD4+ CD25+ Foxp3+ T cells and CD19+ CD24hi CD38 hi B cells (r=0.417, 0.523, respectively, both P<0.05).There was also a negatively correlation between the frequency of circulating pDCs and HbA1c (r=-0.316, P<0.05). Conclusion There is a deficiency of circulating pDCs in peripheral blood of patients with T1DM, which might be correlated with immune imbalance of T1DM, and be involved in the pathogenesis of T1DM. Key words: Diabetes mellitus, type 1; Plasmacytoid dendritic cells; Immune cells