A doctor answered a question if stress was damaging to your health. He wrote
“It's not really the stress we're worried about, since everyone has it, but more so your response to stress. When you come off high-stress mode, you get a rebound effect where you're a lot more prone to infections (your T and B cells go into hiding to avoid a fight and are slow to come back to help you).”
People with AIDS have less T cells. I wonder if the T cells have anything to do with this.