TNFRSF1A and diabetic kidney disease: We also found that serum TNFR-1 levels were significantly elevated in the population with DKD (2.84 ± 0.95 v.s. 2.21 ± 0.34 and 2.10 ± 0.41) (Figure 2G), and there was a significant correlation between serum HMGB1 and serum TNFR-1 levels (R2 = 0.567, p<0.001) (Figure 2H).