SERPINE1 and Sepsis: The relative levels of IL-6 were positively associated with those of IL-8, MCP-1, and PAI-1 (r = 0.6164, P < 0.0001; r = 0.5717, P = 0.0003; and r = 0.3823, P = 0.0234, respectively) in the sera of sepsis patients (Fig. 2A).