A further aspect to consider is the microbiota ability to control the immune cells, a mechanism which can fail during obesity, and involve short-chain fatty acids (SCFAs) function (via G protein-coupled receptors (GPRs)) to increase levels of gut secretory IgA, promote Treg cell responses and strengthen the CX3CR1+ MNP function. This evidence concerns the gene CD79A and obesity due to melanocortin 4 receptor deficiency.