Since all the CF patients in the present study exhibited PF and EMPH, and no standardised and reproducible methodology for the determination of the degree of PF is available, we quantified some serum cytokines, chemokines, growth factors and SP-D - a well-known biomarker of idiopathic pulmonary fibrosis (IPF) (Greene et al. 2002) - that could be altered in these patients and therefore, help us better understand the findings. This evidence concerns the gene SFTPD and cystic fibrosis.