Cytokines secreted by cells that mediate the innate and adaptive immune responses play a critical role in regulating the synthesis of ECM components by fibroblasts. Overexpression and deposition of ECM components are dominant features of fibrotic diseases, including hepatic fibrosis. The contribution of CD4+ Th2 cells to hepatic fibrosis has been well described. Now, in this issue of the JCI, Novobrantseva et al. provide data to suggest that hepatic B cells also play a role in liver injury. In a carbon tetrachloride–induced mouse model of hepatic fibrosis, T cell–deficient mice developed severe liver fibrosis; however, in B cell–deficient animals, hepatic fibrosis was attenuated. This study provides new insight into our understanding of the cells involved in mediating the adaptive immune response that leads to hepatic fibrosis.
Rashpal K. Bhogal, Constantin A. Bona