Conversely, a subject (507) with the histological diagnosis of NSIP (non-specific interstitial pneumonitis) and in the absence of TTF1, SP-C or ABCA3 mutations had considerably reduced level of phosphatidylcholine and such changes of their lipid species profile suggesting the presence of as yet undetermined defects of the pulmonary surfactant system. Here, TTF1 is linked to Interstitial pneumonitis.