An inadequate immune response, with alterations in NK-cell cytotoxicity and delayed proinflammatory cytokine response were found in diet-induced obese mice, which also presented a higher mortality rate upon viral infections.[8,20,44,89,90] Because of the peripheral leptin resistance which leads to impairment in the IL-15 function, diet-induced obesity can affect the T-cell populations in the lung tissue.[8,20,44,91,92]. Here, LEP is linked to obesity due to melanocortin 4 receptor deficiency.