The findings of Zhang et al showed that leptin has no implication in viral replication, but high levels of serum leptin are associated with severe lung injury by AH1N1 in diet-induced obesity in mice.[27] Low leptin levels in patients with obesity suppress the function of memory T-cell, Interferon (IFN)-α, IFN-β, and IFN-γ and could increase the susceptibility to influenza virus infections.[1]. This evidence concerns the gene IFNG and obesity due to melanocortin 4 receptor deficiency.