The data showed a trend towards a significant reduction in serum CCL2 levels in IPF smokers versus IPF non-smokers, consistent with a possible depressive effect of current smoking on a fibrocyte-associated profibrotic chemokine in IPF although the finding needs to be interpreted with caution in view of the low numbers of IPF smokers (U = 2.0, p = 0.02, Fig. 4C). The gene discussed is CCL2; the disease is idiopathic pulmonary fibrosis.