BPIFB4 and COVID-19: Importantly, BPIFB4 values were significantly lower in SARS-CoV-2-positive individuals as compared with SARS-CoV-2-negative ones (57.31 ± 53.13 pg /mL vs 108.1 ± 66.4 pg /mL, p = .0002) pointing to BPIFB4 as a bona fide biomarker inversely related to COVID-19 diagnosis.