TNF and Schnyder corneal dystrophy: The significantly increased plasma level of IL-1β in SCD patients relative to their sibling controls found in this study is consistent with the findings from previous work by Musa et al. (Musa et al., 2010) The cytokines TNF-α and IL-1β impair blood flow and impede recovery from ischaemic episodes by increasing adhesion of sickled erythrocytes to endothelium; (Tian et al., 2005); and so cytokine imbalance is implicated in the pathogenesis of sickle cell crisis.