Inflammation-induced IgA(+) cells dismantle anti-liver cancer immunity

The role of adaptive immunity in early cancer development is controversial. Here we show that chronic inflammation and fibrosis in humans and mice with non-alcoholic fatty liver disease is accompanied by accumulation of liver-resident immunoglobulin-A-producing (IgA+) cells. These cells also express programmed death ligand 1 (PD-L1) and interleukin-10, and directly suppress liver cytotoxic CD8+ T lymphocytes, which prevent emergence of hepatocellular carcinoma and express a limited repertoire of T-cell receptors against tumour-associated antigens. Whereas CD8+ T-cell ablation accelerates hepatocellular carcinoma, genetic or pharmacological interference with IgA+ cell generation attenuates liver carcinogenesis and induces cytotoxic T-lymphocyte-mediated regression of established hepatocellular carcinoma. These findings establish the importance of inflammation-induced suppression of cytotoxic CD8+ T-lymphocyte activation as a tumour-promoting mechanism.Shabnam Shalapour, Xue-Jia Lin, Ingmar N. Bastian, John Brain, Alastair D. Burt, Alexander A. Aksenov, Alison F. Vrbanac, Weihua Li, Andres Perkins, Takaji Matsutani, Zhenyu Zhong, Debanjan Dhar, Jose A. Navas-Molina, Jun Xu, Rohit Loomba, Michael Downes, Ruth T. Yu, Ronald M. Evans, Pieter C. Dorrestein, Rob Knight, Christopher Benner, Quentin M. Anstee, Michael Kari