POSTN and pulmonary fibrosis: Despite the positive correlation found between IFN-γ and periostin, there is also some evidence that IFN-γ can attenuate the expression of periostin [19]; however, in a study where airway hyper-responsiveness and lung fibrosis were investigated, the neutralization of IFN-γ inhibited the combination of eosinophilic infiltration, lung fibrosis, periostin deposition and neutrophilic infiltration [52].