There was a dramatic up-regulation in the level of Il-18 expression in cells with E. coli infection alone, at different time points tested (3, 6, and 9 h), when compared with that in untreated control PMECs (p = 0.004, p < 0.001, and p < 0.001, respectively; Figure 4B). Here, IL18 is linked to escherichia coli infection.