Fig. 6

Gene expression of Complement pathway is significantly up-regulated in severe COVID-19 illness. The histogram (grey bars) represents the null distribution of pathway score calculated by weighted averaging of individual relative expression levels (in severe illness with respect to that in moderate illness) for genes functional in the complement pathway. Only those genes of the pathway present on this platform [13] were included in the analysis. The red vertical line represents the observed pathway score for each set. The position of the red line with respect to the histogram (i.e., toward the right tail) suggests that there is significant up-regulation of the gene set functional in complement pathway (p = 0.03) in severe COVID-19 illness