Although TNF is not elevated in serum or PBMCs from CF relative to HC (Figure 2—figure supplement 2, C), it has been shown by independent research groups, that the CFTR is actively involved in the regulation of TNF, via the NF- κB pathway in lung epithelial cells (Hunter et al., 2010; Vij et al., 2009). This evidence concerns the gene TNF and cystic fibrosis.