CCL2 and crescentic glomerulonephritis: The chemokine MCP-1/CCL2 is expressed by mononuclear and renal cells, facilitating the recruitment of monocytes and macrophages during inflammatory states, including renal pathologies such as lupus nephritis, IgA nephropathy, crescentic glomerulonephritis and diabetic nephropathy, via G-protein coupled CC-chemokine receptor-2 (CCR2) [45].