People with high blood pressure exhibit low-grade inflammation in their kidneys, involving T cells and macrophages, which impairs the kidney's ability to excrete salt.

“it does appear that salt really is important and one of the key discoveries was that the kidneys are often normally handle salt fine but they develop or acquire a change in the kidneys that lead them to hold on to sodium and the mechanism has been identified just in the last few years it's due to the fact that there's an inflammatory inflammation that occurs in the kidney and that inflammation which is driven by t cells and macrophages causes a constriction of the blood vessels that leads to low-grade ischemia in the kidney and that ischemia can translate into increased sodium absorption”