TNF and obesity due to melanocortin 4 receptor deficiency: Lastly, we wanted to see if the treatment class, disease duration, obesity, alcohol consumption, smoking habit, or gender has an effect on serum levels of TNF-α, IL-17A, IL-17F, and IL-12/23 at the onset of treatment or after 12 weeks (Table 4, Table 5, Table 6 and Table 7).