In addition to lipotoxicity, some adipokines as IL-6 and leptin that get higher in obesity also impair the cytotoxic activity of NK cells (Lamas et al., 2013; Cifaldi et al., 2015; Bähr et al., 2017; Bähr et al., 2020). Here, IL6 is linked to obesity due to melanocortin 4 receptor deficiency.