CD9 and metabolic dysfunction-associated steatohepatitis: We observed a very low number of these activated macrophages in our data set; only 1% of the total macrophages (41/3,613 cells) were TREM2+CD9+ (Fig. 4B), suggesting that the population of TREM2+CD9+ macrophages potentially are less prevalent in human NASH compared to mouse NASH models12.