HAMP and nutritional disorder: Hepcidin suppression without recovery from iron deficiency raises several possibilities:The degree of increased ERFE in PV patients is significantly lower relative to that in patients with β-thalassemia in whom erythropoiesis is also expanded but ineffective, resulting in the accumulation of basophilic and polychromatophilic erythroblasts with a higher expression of ERFE [87] (Fig. 4).