Excess cortisol in Cushing's syndrome leads to which effect on the immune system?

• A. Increased antibody production
• B. Impaired antibody function
• C. Increased lymphocyte proliferation
• D. Enhanced neutrophil activity

Answer: (B)

Excess cortisol suppresses immune function, especially the aspects of the immune system that rely on antibodies. High cortisol reduces B-cell activity and antibody production, and it also dampens the overall antibody response so antibodies are less effective at recognizing and neutralizing antigens. This is why impaired antibody function is the best choice—the immune system’s humoral defense is weakened rather than strengthened by cortisol excess.

Cortisol can raise circulating neutrophil counts by demargination, but it does not enhance neutrophil function; it impairs chemotaxis and phagocytosis. It also suppresses lymphocyte proliferation and T-cell activity, further illustrating the overall immunosuppressive effect.