Viral infections in neutropenia--current problems and chemotherapeutic control.

The risk of infection in immunocompromised patients is determined by the nature, degree and duration of the immunosuppressive disease or therapy. Although neutropenia is clearly related to an increased risk of infection, these infections are typically caused by bacteria and fungal pathogens rather than by viruses. Viral infections are predominantly associated with defects in cellular immune function and might not be expected to cause problems in patients whose primary disease is accompanied by neutropenia. The net state of the patient's host-defence mechanisms is, however, a complex interplay between a number of factors, primary among which are the underlying disease and the nature of the therapy being given. In certain periods of neutropenia, therefore, particularly that occurring early after bone marrow transplantation, viral infections are commonly seen. The viruses responsible are chiefly the herpesviruses, both primary infections and reactivation, although other viruses are assuming recognized importance in this setting. This article provides a review of the infections that are encountered during the period of neutropenia in immunocompromised patients and the options available for chemotherapeutic management.