The mind and the immune system have been shown to be intimately linked, and scientists are consistently finding that doing good deeds benefits one' s immune system  The bone marrow and spleen, which produce the white blood cells needed to fight infection, are both connected by neural pathways to the brain
Recent research has shown that the activity of these white blood cells is stimulated by beneficial chemicals produced by the brain as a result of magnanimous behavior
magnanimity is beneficial to one's own interests