Use of a pharmaceutical kit for the manufacture of a medicament for the treatment of idiopathic pulmonary fibrosis after the successfull pre-treatment of underlying infections, comprising (i) a package comprising interferon gamma, optionally together with a pharmaceutically acceptable carrier, diluent or excipient, wherein the patient has a pool of polynucleotide sequences or subsequences which are either underexpressed or overexpressed in idiopathic pulmonary fibrosis cells compared to other lung disorders, wherein the overexpressed sequences or subsequences are mucin 4, tracheobronchial (SEQ ID NO:6); mucin 5, subtype B, tracheobronchial (SEQ ID NO:12); myosin regulatory light chain 2, smooth muscle isoform, (SEQ ID NO:19); insulin-like growth factor binding protein 2, (SEQ ID NO:23); cadherin 1, type 1, E-cadherin (epithelial) (SEQ ID NO:29); connective tissue growth factor (SEQ ID NO:50); keratin 15 (SEQ ID NO:71); cytokeratin 17 (SEQ ID NO:118); matrix metalloproteinase 7 (matrilysin, uterine) (SEQ ID NO:82); cytokeratin 4 (SEQ ID NO:116); insulin-like growth factor 1 receptor (SEQ ID NO:148); keratin 5 (epidermolysis bullosa simplex, Dowling-MearaKobnerWeber-Cockayne types): (SEQ ID NO:149); transforming growth factor β 1 (SEQ ID NO:151); and the underexpressed sequences or subsequences are surfactant, pulmonary-associated protein C (SEQ ID NO:156); interferon, gamma-inducible protein 30 (SEQ ID NO:181); interleukin 7 receptor (SEQ ID NO:214); pulmonary surfactant protein (SEQ ID NO:222); surfactant, pulmonary-associated protein A2 (SEQ ID NO:227); interleukin 13 receptor, alpha 2 (SEQ ID NO:257); interferon-gamma-inducible indoleamine 2,3-dioxygenase (SEQ ID NO:276); relaxin 1 (SEQ ID NO:313), characterised in that the treatment comprises the diagnostic step of determining whether or not the patent has the above states pool of under- or overexpressed polynucleotide sequences or subsequences in IPF. (i) a package comprising interferon gamma, optionally together with a pharmaceutically acceptable carrier, diluent or excipient, wherein the patient has a pool of polynucleotide sequences or subsequences which are either underexpressed or overexpressed in idiopathic pulmonary fibrosis cells compared to other lung disorders, wherein the overexpressed sequences or subsequences are mucin 4, tracheobronchial (SEQ ID NO:6); mucin 5, subtype B, tracheobronchial (SEQ ID NO:12); myosin regulatory light chain 2, smooth muscle isoform, (SEQ ID NO:19); insulin-like growth factor binding protein 2, (SEQ ID NO:23); cadherin 1, type 1, E-cadherin (epithelial) (SEQ ID NO:29); connective tissue growth factor (SEQ ID NO:50); keratin 15 (SEQ ID NO:71); cytokeratin 17 (SEQ ID NO:118); matrix metalloproteinase 7 (matrilysin, uterine) (SEQ ID NO:82); cytokeratin 4 (SEQ ID NO:116); insulin-like growth factor 1 receptor (SEQ ID NO:148); keratin 5 (epidermolysis bullosa simplex, Dowling-MearaKobnerWeber-Cockayne types): (SEQ ID NO:149); transforming growth factor β 1 (SEQ ID NO:151); and the underexpressed sequences or subsequences are surfactant, pulmonary-associated protein C (SEQ ID NO:156); interferon, gamma-inducible protein 30 (SEQ ID NO:181); interleukin 7 receptor (SEQ ID NO:214); pulmonary surfactant protein (SEQ ID NO:222); surfactant, pulmonary-associated protein A2 (SEQ ID NO:227); interleukin 13 receptor, alpha 2 (SEQ ID NO:257); interferon-gamma-inducible indoleamine 2,3-dioxygenase (SEQ ID NO:276); relaxin 1 (SEQ ID NO:313), characterised in that the treatment comprises the diagnostic step of determining whether or not the patent has the above states pool of under- or overexpressed polynucleotide sequences or subsequences in IPF.