BPIFB4 and COVID-19: As adjunct value, we previously reported the role of the bactericidal/permeability-increasing fold-containing family-B-member-4 (BPIFB4) protein in mitigating the cytotoxic and pro-inflammatory effects of SARS-CoV-2, founding new prognostic significance for BPIFB4 in terms of severity for patients with COVID-19 [20].