CCL18 and idiopathic pulmonary fibrosis: A group of eight proteins has recently been propose as disease progression serum markers in Idiopathic Pulmonary Fibrosis (IPF): KL-6, surfactant protein A, and MMP-7, CCL-18, S100A12, IL-8, ICAM-1 and VCAM-1 [14,18,22-25].