However, given the more recent study of Nishimura et al.[17], which demonstrates a role for CD8+ T-cells in mediating the inflammation and metabolic abnormalities of obesity, and the data obtained in the current study, a more likely explanation is that much, if not all, of the improvements in metabolic function and inflammation observed in the β2-microglobulin null mouse are due to the absence of CD8+ T-cells. Here, CD8A is linked to obesity due to melanocortin 4 receptor deficiency.