IL17A and obesity due to melanocortin 4 receptor deficiency: Although obesity is linked to inflammation through multiple mechanisms [47], in this study exploring CD4+ T helper cell responsiveness, the extent of TCR-mediated cytokine production was restricted to Th1 and Th17 cells, as evident by the significantly higher levels of IFNγ and IL-17 in the obese versus lean subject cells (Figure 6c).