TLR4 and peritonitis: In particular, it has been shown that peritoneal macrophages and mast cells secrete CXCL1 in a TLR4-dependent manner in LPS- or zymosan-induced peritonitis, and these cells, together with specialized omental mesothelial cells which also produce CXCL1, coordinate the recruitment of neutrophils to capture peritoneal contaminants76,79.