Plasma ACBP concentrations were associated with age (r=0.29, p<0.001), with levels of GDF-15, a biomarker of aging (r=0.29, p<0.0001) (Table 2) (28), as well as with ferritin levels, which is an established marker of COVID-19 severity (r=0.3, p<0.001) (Table 2) (7). This evidence concerns the gene GDF15 and COVID-19.