The presence of TLRs on the epithelial surface, in the absence of any infection, appeared to be able to trigger activation of the downstream pathway (Fig. 1F), as we could detect phosphorylated IRAK4 (p-IRAK4) in these cells, and p-IRAK4 levels increased with the cells reaching confluence and differentiating (Fig. 1E). The gene discussed is IRAK4; the disease is infection.