Figure 5. PBMC stimulation test. Cultured human corneal endothelial cells were used as stimulating cells. Cysteamine (CYS) suppressed PBMC proliferation in a dose-dependent manner (p<0.001; Kruskal–Wallis test). PHA-stimulated PBMCs served as the positive control and unstimulated PBMCs served as the negative control. *: statistically significant by the Mann–Whitney U test.