LEP and obesity due to melanocortin 4 receptor deficiency: Notably, obesity leads to splenic NK senescence, resembling changes seen in aging.93 Further, plasma from obese individuals is sufficient to induce senescence in cytotoxic T cells,94 and increased leptin levels (hallmark of obesity) induce B cell senescense.95 Altered immune responses of these cells to influenza in obesity96 may lead to impaired control of viral replication and increased disease severity.