Similarly, the levels of Th1 (OR 0.8211; 95% CI 0.7184 to 0.9385; p=0.0040), as well as the expression levels of IL-4 from CD4+ Th2 cells (OR 1.2572; 95% CI 1.0341 to 1.5285; p=0.0220) and IL-13 from CD4+ Th22 cells (OR 0.9276; 95% CI 0.8674 to 0.9920; p=0.0280) were positively correlated with the occurrence of critical COVID-19 (Table 2C). Here, IL4 is linked to COVID-19.