PDCD1 and metabolic syndrome: Although we observed an expansion of Tregs in Ldlr−/−Pd1−/− mice, net effects of PD-1 deficiency seemed to clearly favor the pro-inflammatory arm of the regulatory/pro-inflammatory T cell response, therefore one could speculate that increased systemic T cell-dependent inflammation, including sites such as the liver or adipose tissue, might enhance diet-associated dyslipidemia and exacerbate atherogenesis in Ldlr−/−Pd1−/− mice.