IL4 and liver disorder: Distinct from conventional T lymphocytes, NKT cells preferentially taking the liver as their home, play a pathogenic role in various types of liver disease (Martin-Murphy et al., 2013; Schrumpf et al., 2015; Bandyopadhyay et al., 2016), secrete cytokines like IFN-γ, IL-4, and IL-17, and regulate the balance of pro- and anti-inflammatory responses in liver diseases (Wang and Yin, 2015; Bhattacharjee et al., 2017; Li and Hua, 2017).