Nowadays, we cannot deny that in our life there is a separation by our power or capability that is called social status. A studying in America has already shown that social status such as wealthy and poor it influence to health and welfare of people, even for monkeys.
Furthermore, a research at the Yerkes National Primate Research Centre at Emory University regarding rhesus monkeys has found that high-rank monkeys tended to have more better of natural killer cells. In the other words, it is mean that monkeys which have higher rank in their group have more better resistance against viruses than monkeys which have lower rank.
Meanwhile, when the monkeys were resorted, at the moment the low-rank monkeys were moved into the high-rank group, and the research found that it very affected to their immune bodies. Their immune bodies which low at the past became more better as their enjoyed their life with their new members in the high-rank group.
source : newscientist