Because IL-8 and TNF-α are inflammatory mediators likely to participate in the response to cutaneous infections, we used real-time RT-PCR (Fig 2) and ELISA (Fig 3) to measure the effects of P5 (0.8 or 1.6 μM) on the expression of IL-8 and TNF-α 24 h after pre-infection (1x108 CFU/ml) of HKs with P. acnes. We found that relative levels of both IL-8 and TNF-α mRNA (Fig 2A and 2B, respectively) and protein (Fig 3A and 3B respectively) were significantly upregulated after P. acnes infection, and those responses were significantly inhibited by P5. The gene discussed is CXCL8; the disease is infection.