TREM2 and obesity due to melanocortin 4 receptor deficiency: In addition, we found that while only approximately 47% of the CD9+ ATMs (F4/80+CD11b+CD9+) express Trem2, an overwhelming majority (~86.7%) of Trem2+ ATMs (F4/80+CD11b+Trem2+) expresses CD9 (Fig. S7C), corroborating a previous finding that Trem2+ expression emerges after CD9+ ATMs over the course of obesity (Jaitin, Adlung et al. 2019).