CD9 and obesity due to melanocortin 4 receptor deficiency: Obesity-imprinted immune states persist after WL and intensify with WC: T-cell exhaustion (PD-1/TIGIT module) remains; Tregs stay low with reduced Il1rl1 (ST2); DCs retain mature/activated signatures (Ccr7hi/Fscn1hi/Cd274hi); classical monocytes keep lipid-handling/activation genes (Trem2, Cd36, Cd9, Cd81/63/86)