Figure 2. Distribution of serum interleukin (IL)-22 concentrations in controls (n=30), non-diabetic retinopathy (NDR, n=9), non-proliferative diabetic retinopathy (NPDR, n=10) and proliferative diabetic retinopathy (PDR, n=10) were measured by FlowCytomix. One-way ANOVA with a post-hoc Scheffe test showed that the serum level of IL-22 was significantly lower in NPDR compared with the controls (p=0.023). No significant difference was found among NDR, NPDR, and PDR groups.