IL6 and obesity due to melanocortin 4 receptor deficiency: Obesity often correlates with heightened levels of systemic pro-inflammatory markers like C-reactive protein, TNF-α, TGF-β, leptin, and IL-6 [24, 25], and we have shown that reducing TNF-α and TGF-β1 levels improved AHR and fibrosis in the same HFD-induced obesity model [3, 25].