Regulation of iron homeostasis through the erythroferrone-hepcidin axis in sickle cell disease

Sickle cell disease (SCD) has a distinct pattern of transfusional iron overload (IO) when compared to transfusion-dependent beta-thalassaemia major (TDT). We conducted a single institution prospective study to evaluate plasma biomarkers of iron regulation and inflammation in patients with SCD with IO (SCD IO cases,n = 22) and without IO (SCD non-IO cases,n = 11), and non-SCD controls (n = 13). Hepcidin was found to be inappropriately low, as evidenced by a significantly higher median hepcidin/ferritin ratio in non-SCD controls compared to SCD IO cases (0 center dot 3 vs. 0 center dot 02,P < 0 center dot 0001) and SCD non-IO cases (0 center dot 3 vs. 0 center dot 02,P < 0 center dot 0001), suggesting that certain inhibitory mechanism (s) work to suppress hepcidin in SCD. As opposed to the SCD non-IO state, where hepcidin shows a strong significant positive correlation with ferritin (Spearman rho = 0 center dot 7,P = 0 center dot 02), this correlation was lost when IO occurs (Spearman rho = -0 center dot 2,P = 0 center dot 4). Although a direct non-linear correlation between erythroferrone (ERFE) and hepcidin did not reach statistical significance both in the IO (Spearman rho = -0 center dot 4,P = 0 center dot 08) and non-IO state (Spearman rho = -0 center dot 6,P = 0 center dot 07), patients with highest ERFE had low hepcidin levels, suggesting that ERFE contributes to hepcidin regulation in some patients. Our results suggest a multifactorial mechanism of hepcidin regulation in SCD.