Cells within cluster 0, 1, 2, 3, and to a lesser extent cells within cluster 5 up-regulated genes associated with FRCs [57] in response to infection, including Pdpn, Pdgfra, Pdgrfb, Vim, and Col6a3, as well as secreted factors such as Vefga and Tnfsf13b (encoding for BAFF) (S3A Fig). Here, PDGFRA is linked to infection.