IL4 and Hepatic fibrosis: Importantly, M-CSF gene expression was not altered during acute S. mansoni infection (Figure 1e), consistent with its role in promoting the differentiation and survival of macrophage populations that further the development of liver fibrosis during the later stages of disease.27 Acute S. mansoni infection also had dramatic effects on the Th2 and regulatory cytokine milieu in the liver, with elevated transcription of genes encoding IL-4, IL-13 and IL-10 detected at week 6 post infection, as expected (Figure 1e).