IFNG and idiopathic pulmonary fibrosis: There was no significant difference in the genotype or allele distributions of polymorphisms in TNF-α (−308), IFN-γ (+874), IL-6 (−174), IL-10 (−1082, -819 and −592), and TGF-β1 (codons 10 and 25) between the IPF and healthy control groups (all p > 0.05).