IL6 and Schnyder corneal dystrophy: Serum cytokine levels, including IL-1β, IL-6, IL-8, IL-10, TNF-α and IFN-γ, were not significantly different between SCD-heparin and SCD-citrate groups, although IL-1β and IL-8 trended higher in the SCD-heparin compared to the SCD-citrate group.