Fig. 4

Dysfunctional immunity in H7N9 patients co-infected by A. baumannii. The plasma cytokines IL-6 (a) and IL-8 (b) in the H7N9-A. baumannii co-infected patients (H7N9 + AB) are higher than the H7N9 control patients (H7N9 group) during week 2 (Day 8–14), week 3 (Day 15–21) and week 4 (Day 22–28) after the admission. In contrast, IL-6 and IL-8 in the H7N9 control patients were decreasing gradually from week 1 (Day 1–7) to week 4 (Day 22–28) after hospitalization. Through the analysis of T-lymphocyte subtypes, the ratio of T-cells in total white blood cells on admission (c) was compared between H7N9 + AB cases and H7N9 controls and A. baumannii pneumonia control patients (AB group). The ratio of CD4⁺ T-cells/CD8⁺ T-cells (d) was also calculated among cases and controls. The time for CD4⁺ T-cell count restoring was longer for H7N9 + AB patients (e). The CD3⁺, CD4⁺ and CD8⁺ T-cell counts were compared between the co-infected cases and controls (f). The influenza virus-specific T-cell responses (g) were detected through ELISPOT by using the freshly-isolated PBMCs from the patients. H7N9-specific peptide pools and conserved peptide pools were used as the stimulators