CD4+ T lymphopenia in circulation is also a major comorbidity of severe/critical COVID-19 patients who suffer from sepsis.25,26 We also observed that the inverse correlation of CD4+ (Fig. 1e) and CD8+ T cell counts (Supplementary Fig. 1h) and PICC levels (IL-6, IL-1β, IL-8 and IFNγ) in bronchoalveolar lavage fluids of COVID-19 patients hospitalized in 2020 (Supplementary Table 1), whose symptoms transformed from severe to mild pneumonia after symptomatic treatments (Fig. 1f). This evidence concerns the gene IL6 and susceptibility to pneumonia measurement.