CD40LG and obesity due to melanocortin 4 receptor deficiency: Studies have shown that adipose-resident macrophage numbers are positively related to circulating inflammatory markers such as CRP and TNFα (CD40LG belongs to TNF family members), and adipose inflammation is thought to be the main source of systemic inflammation and metabolic disorder associated with obesity (Paepegaey et al., 2015; Kunz et al., 2021).