CHI3L1 and idiopathic pulmonary fibrosis: Among those we can identify surfactant protein A or SP-A, surfactant protein D or SP-D which has recently be identified to be correlated with pulmonary function and mortality in IPF [8], the Krebs von den Lungen 6 or KL-6, type A immunoglobulin or IgA, periostin [9–13], insulin-like growth factor binding protein or IGFBP-2 [14] and a chitinase-3-like-1 human cartilage glycoprotein or YKL-40 [15–16] which were found to be increased in serum from IPF patients.