LIF and susceptibility to pneumonia measurement: The ROC analysis revealed that chemokines: IP-10 and MIG, and GFs: basic-FGF, PDGF-BB, GM-CSF, GRO-α, LIF, and INF-γ can be useful parameters for differentiating between asymptomatic/mildly symptomatic COVID-19 patients and patients with pneumonia without respiratory failure (Table 5).