Infection in the organ transplant recipient. An overview.

Considerable progress has been made in elucidating the factors involved in the pathogenesis of infection in the organ transplant patient. One of the general principles that has emerged is that the risk of clinical infection, particularly opportunistic infection, is determined largely by the interaction between the patient's net state of immunosuppression and the epidemiologic exposures the patient encounters. The two major factors that determine the net state of immunosuppression are the nature of the exogenous immunosuppressive therapy that is administered and whether or not infection is present with one or more of the immunomodulating viruses (particularly cytomegalovirus, Epstein-Barr virus, and the hepatitis viruses). Finally, the therapeutic prescription for the transplant patient has two components--an immunosuppressive component to prevent and treat rejection and an antimicrobial component, which is linked to the intensity of the immunosuppressive therapy required, to make this safe. This reflects the recognition that the two major barriers to successful transplantation, rejection and infection, are closely tied together by the current requirement for lifelong immunosuppressive therapy. Progress in one area will have beneficial effects on the other.