Higher IL-6 plasma levels were associated with higher peak D-dimer and peak CRP in ICU, which can be explained by IL‐6 causing an increase acute phase reactants, such as C‐reactive protein, fibrinogen, and hepcidin.39 In addition, the ratio of neutrophils to lymphocytes was positively correlated with IL-6 plasma levels but not with HMGB1, suggesting IL-6 plays a more important role in the substantial reduction of the peripheral lymphocytes associated with immunoparalysis in patients with COVID-19.36 Here, HAMP is linked to COVID-19.