Summary

In 2013, the idea of the hyperferritinemic syndrome was introduced to suggest the possible inflammatory properties of ferritin in contributing to the pathogenesis of four diseases, namely Still’s disease, macrophage activation syndrome (MAS), septic shock, and catastrophic antiphospholipid syndrome [1]. Based on this concept, ex vivo and in vitro studies were performed reporting the inflammatory properties of the heavy subunit of ferritin (FeH) in inducing the commitment of macrophages toward an inflammatory phenotype, production of pro-inflammatory cytokines, and the direct stimulation of NLRP3 and NF-kB pathway [2,4]. In addition, recent in vivo studies have established the pathogenic role of hyperferritinemia [4-6], mainly triggering a Still’s disease-like phenotype in a wild type murine model by the aberrant activation of immune cells and production of inflammatory mediators [5]. Moreover, the hyperferritinemic syndrome arena has seen many recent developments due to the rapid accrual of knowledge in coronavirus disease 2019 (COVID-19) [6,7]. Specifically, the appearance of hyperferritinemia is increasingly recognized to be associated with a more severe patient phenotype at higher risk of poor prognosis due to the appearance of the cytokine storm syndrome [8], which is a hyper-inflammatory state due to overwhelming massive release of inflammatory mediators and rapidly evolving to multiorgan failure [9].