Figure 4.

Impairment of peripheral blood Th cell subsets maturation and ‘polarization’ in patients with COVID-19. Abnormalities of Th cell maturation were linked with the decrease in ‘naïve’ CD4 T cells and increase of effector Th cell subsets. The relative number of activated (CD38+, HLA-DR+, or ICOS+) Th cell and their subsets were increased during the acute phase of SARS-CoV-2 infection. An imbalance of ‘polarized’ T cell subsets was frequently found in patients with COVID-19, being characterized by relatively high numbers of Th2 cells and low levels of Th17 and/or Tfh cells.