The involvement of IL-1β signalling in chemokine expression shown in the current study is consistent with its known influence outside the retina, including its ability to induce CCL2 in pancreatic β-cells [35, 36], and spur up-regulation of CXCL1 in intestinal tissue during infection with Clostridium difficile [37]. This evidence concerns the gene CXCL1 and infection.