CXCL8 and infection: The IL-8 expression data by macrophage cells samples showed a statistically-significant increased expression of this cytokine in response to the three serotypes analyzed compared to the unstimulated control condition, serotype a (p = 0.0025), b (p = 0.0231), and c (p = 0.0062) at 2 h of infection and serotype a (p = 0.0014), b (p = 0.0102) and c (p = 0.0070) at 24 h of infection.