@achin In animal models, stress stimulates the entire immune system, bone marrow included, which leads to the hyperactive production of immune cells.
Humans with depression also produce more white blood cells, particularly monocytes. The release of these important immune cells into the bloodstream prompts further response elsewhere in the body. Inflammation is an immune response to infection or other stresses on the body. High inflammation levels are associated with autoimmune disorders and can be risk factors for cardiovascular illness or other ailments.