For instance, there is a significant increase in levels of pro-inflammatory cytokines such as TNF-α and IL-8 in the lungs of patients with IPF (Kapanci et al., 1995), and TNF-α has been shown to be important in bleomycin-induced fibrosis (Ortiz et al., 1998). This evidence concerns the gene TNF and idiopathic pulmonary fibrosis.