IL18 and Schnyder corneal dystrophy: Chronic upregulation of inflammatory cytokines such as IL-1β, TNF-α, IL-6, and IL-18 is usually found in the blood of SCD patients (Harlan, 1985; Pober, 1988; Francis and Haywood, 1992; Malave et al., 1993; Pathare et al., 2004).