How much these values compare to cytokine levels of healthy subjects is currently unknown (study ongoing), although from previously published data steady state SCD patients seem to have increased levels of IL-6, IL-8 and IL-18 (which in normal subjects are ≤ 10 pg/ml for IL-6 and IL-8, and around 200 pg/ml for IL-18), suggesting a partially upregulated inflammatory level in steady state SCD. Here, IL18 is linked to Schnyder corneal dystrophy.