During MCD-induced NASH, NKT cells were accumulated via Hedgehog (Hh) pathway activation or IL-15 stimulation, and subsequently NKT cells promoted HSC activation to become myofibroblasts (MF) through production of osteopontin (OPN) and hedgehog (Hh) ligands (103–105). Here, IL15 is linked to metabolic dysfunction-associated steatohepatitis.