How do glucocorticoids primarily affect the immune system?

Glucocorticoids primarily suppress the immune system, which is a critical function that allows them to manage conditions involving excessive immune responses and inflammation. These hormones are produced by the adrenal cortex and play a significant role in modulating various immune functions.

The suppression of the immune system occurs through several mechanisms. Glucocorticoids influence the expression of anti-inflammatory genes while inhibiting pro-inflammatory cytokines, which reduces inflammation and immune activity. They act on various leukocytes, including T cells and macrophages, to inhibit their proliferation and function. This leads to a decrease in the immune response, making glucocorticoids essential in treating autoimmune diseases, allergic reactions, and acute inflammatory conditions.

Other options suggest either stimulation of immune responses or enhancement of inflammation, which contradicts the known immunosuppressive action of glucocorticoids. Additionally, while glucocorticoids can impact the production and lifespan of certain white blood cells, they do not primarily serve to boost white blood cell production. Instead, the overall outcome of their action tends to lead towards immunosuppression, which underscores their use in clinical settings when controlling inappropriate or excessive immune responses is necessary.