Given the importance of the IL-17A in liver fibrosis42 and the finding of the hepatic fibrosis signaling pathway mentioned above, we elected to investigate changes in expression of known markers of cholangiocyte-driven fibrosis genes in our scRNA-seq; however, none of these genes were significantly different between the samples (Supplemental Figure S5, Supplemental Digital Content 1, http://links.lww.com/HC9/A900).43, 44 This suggests that fibrosis in PSC is likely multifactorial and perhaps not driven by IL-17A signaling in cholangiocytes itself but by other factors in the microenvironment. The gene discussed is IL17A; the disease is hepatitis A virus infection.