TNF and idiopathic pulmonary fibrosis: Finally, when compared to the same parameters identified in the IS of IPF patients23, it is interesting to note that there exist similarities between both diseases reflected by elevated TGF-β, IL-8 and MMP-7 levels, but also difference: IGFBP-1 and YKL-40 levels are elevated in SSc patients and not different from HV in IPF; IGFBP-2 and MMP-9 levels are similar to HV in SSc patients and higher in IPF patients and IGFBP-3 and TNF-α are present in IPF patients but not in SSc ones.