IL6 and obesity due to melanocortin 4 receptor deficiency: Circulating levels of IL-6 are significantly higher in patients with overweight (BMI range: 25–29.9 kg/m2) and obesity (BMI > 30 kg/m2), and correlate positively with BMI in patients with grade III obesity, and negatively with serum HDL-C in patients with grade II obesity [44].