Patients with transplanted organs are prone to host versus graft rejection since their own immune system tends to attack the grafted organ because of recognition of the grafted tissue as foreign matter. In the prevention and treatment of this common problem patients are given glucorticoids or other immunosupressants. Glucocorticoids have an immunosuppressant action and so they reduce the aggression of the immune system against the graft.
The immune action however is also very important for the individual. The immune system defends the body against invasion and infection by pathogenic agents (virus, bacteria, toxins) besides being fundamental for the elimination of modified cells that may proliferate and cause cancer.
Patients receiving immunosuppressants like glucocorticoids are thus under increased risk of infectious and neoplastic diseases.