CCL2 and cyst: Specifically, macrophages were shown to accumulate and home to cystic epithelium contributing to cyst growth in both orthologous (16, 19) and nonorthologous (21) models of PKD, whereas blockade of macrophage colony stimulating factor CSF1 (21) or monocyte chemoattractant protein MCP-1 (19) in these models reduced macrophage numbers and cyst formation.