Fig. 5
Distinct cytokine profiles related to COVID-19 severity at different time intervals after symptoms onset. Principal component analysis (PCA) of 12 serum cytokines evaluated in patients with COVID-19 with diverse disease severity at day 1–7, 8–14, and > 14 time intervals. A, B, C, at day 1–7, 8–14, and > 14time intervals, respectively. A-, B-1, C-1, Biplots display the correlation vectors that indicate the two-dimensional projection of the loading for each cytokine included in the specific PCA. A-2, B-2, C-2, PCA tables displaying correlation coefficients for cytokines loaded on the three principal components (PCs) derived from the data analysis. The color of the dots in each cytokine row represents the degree of correlation between that variable and the eigenvector of each principal component. Correlation coefficients with higher absolute values were regarded to be important (dark) in determining the PC. A-3, A-4, A-5, Levels of PC1, PC2, and PC3 are depicted for each respiratory severity group. Dim, dimension. P values were calculated by a two-tailed Mann–Whitney U-test for nonparametric comparisons. *P < 0.05, **P < 0.01 and ***P < 0.001 show significance between COVID-19 subgroups.
