We further performed interaction analysis of CD28-rs3116494 and CD80-rs3850890 with DKD and found a risk-allele dose-dependent effect on DKD occurrence (P = 0.0098); subjects carrying the rs3116494 G allele and rs3850890 TT genotype showed the highest prevalence of DKD (Figure 1(f)). This evidence concerns the gene CD28 and diabetic kidney disease.