Relationship between myeloid-derived suppressor cells and immunoglobulin G4 in patients with type 1 diabetes mellitus

Objective To assess the relationship between serum myeloid-derived suppressor cells (MDSCs) and immunoglobulin G4 (IgG4) in patients with type 1 diabetes mellitus (T1DM). Methods Thirty patients with T1DM and 20 patients with T2DM were selected at the Second Affiliated Hospital of Shantou University Medical College from January 2015 to January 2017; another 20 healthy subjects were selected from January 2015 to January 2017 as a control group. The frequency of MDSCs in peripheral blood was detected by enzyme-linked immunosorbent assay and flow cytometry. The t-test, chi-square test, Mann-Whitney U test and spearman correlation analysis were used to compare the changes of serum IgG4 content, MDSCs frequency and the correlation between serum IgG4 and MDSCs. Results Serum IgG4 level was (0.92±0.79) g/L in the T1DM group, (0.54±0.33) g/L in the T2DM group, and (0.34±0.15) g/L in the normal control group. Compared with the control group, serum IgG4 levels in the T1DM and T2DM groups were significantly higher (t=4.9, P<0.001; t=2.466, P=0.01). Compared with the T2DM group, serum IgG4 level in the T1DM group was significantly higher (t=2.83, P=0.007). The frequency of MDSCs in the T1DM group was significantly higher than those in the control group (Z=-9.650, P<0.01) and in the T2DM group (t=2.899, P=0.005). Serum IgG4 levels in T1DM patients were positively correlated with the frequency of MDSCs (r=0.482, P<0.05). Conclusion MDSCs and IgG4 increase in patients with T1DM, and they have a positive correlation, which deserves further research. Key words: Type 1 diabetes mellitus; Myeloid-derived suppressor cells; Immunoglobulin G4