Relationship between Th17 cells and type 1 diabetes mellitus

Objective To assess the role of Th17 cells in the development of type 1 diabetes mellitus (T1DM). Methods Thirty-nine T1DM patients (T1DM group, 21 males, 18 females, mean age (31±13) years), 40 type 2 diabetes mellitus (T2DM) patients(T2DM group, 28 males, 12 females, mean age (36±8) years) and 36 healthy volunteers (control group, 19 males, 17 females, mean age (29±12) years) admitted to our hospital during January 2009 and December 2010 were enrolled in this study. Plasma levels of interleukin-17A (IL-17A) and B cell activating factor were measured by enzyme-linked immunosorbent assay (ELISA) and the frequency of Th17 cells in peripheral blood mononuclear cells was tested by flow cytometry. The expressions of RORγt gene was measured by real-time quantitative polymerase chain reaction. t test was used for data analysis. Results In comparison with the control group, Th17 cells ((4.2±0.8)% vs (1.8±0.6)%, t=8.338, P=0.005), IL-17A level ((2.42±0.24) vs (1.37±0.37) ng/L, t=5.601, P=0.021), RORγt mRNA expression (5.0±1.3 vs 1.4±1.0, t=38.959, P=0.000), and B cell activating factor ((91±5) vs (66±8) ng/L, t=6.211, P=0.015) of the T1DM group were increased. Partial two-tailed correlation analysis showed that there was a positive correlation between IL-17A and B cell activating factor in the T1DM group (r=0.623, P=0.000). Step-wise linear regression analysis indicated that Th17 cells was negatively correlated with fasting C-peptide(r=-0.069, P=0.011). Conclusion Th17 cells might play a role in the development of T1DM through stimulating B cell activating factor. Key words: Diabetes mellitus, type 1; Interleukin-17; B-cell activating factor; Genes