The effect due to the annual increase in age on MIG/CXCL9 may not seem much, but an additional 56 years of life doubles the level for this cytokine and is sufficient, with our patients with IPF (Table 1) being a couple of decades older than our patients with SSc, to suggest that patients with either IPF or lcSSc have similar increased levels of MIG/CXCL9 if not adjusted for confounding due to age (Fig. 1). This evidence concerns the gene CXCL9 and systemic sclerosis.