The underlying theory of blood type diets is that people with different blood types digest lectins differently, and that if people eat food that is not compatible with their blood type, they will experience many health problems.
Leptin is a potent stimulator of the immune system. Leptin receptors on monocytes cause the release intracellularly of STAT3 which cause the monocytes to release IL-6, IL-12 and TNF alpha. The IL-6 goes to the liver and increases production of CRP.
Leptin is a small, hormone-like protein that is also present in colostrum. It can suppress appetite and is involved in regulating the metabolism of fats. Insulin, which is also found in colostrum, and leptin work together. When insulin is present, mature fat cells (adipocytes) in the body release leptin. It is also believed that the size of the fat cells is a major factor in determining how much leptin will be released, small fat cells release more than large fat cells.