This hypothesis is further supported by the behavior of IPF macrophages infected with latent HSV-1, since there was a notable 17-fold increase of SDF-1a in IPF infected cells compared to the mock infected healthy macrophages, suggesting that given an infectious stimuli the macrophages promote at least one component of the angiopoietic axis. Here, CXCL12 is linked to idiopathic interstitial pneumonia.