Community respiratory virus infections in immunocompromised patients with cancer

Community respiratory viruses, such as respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses, adenoviruses, and picornaviruses, are an important cause of respiratory disease in the immunocompromised adult with cancer. Recent studies have demonstrated that a minimum of 31% of adult bone marrow transplant (BMT) recipients and 18% of adults with leukemia who are hospitalized with an acute respiratory illness have a community respiratory virus infection. The temporal occurrence of these infections in immunocompromised patients tends to mirror their occurrence in the community. The clinical illnesses range from self-limited upper respiratory illnesses to fatal pneumonias, depending on the type of virus and the type and degree of immunosuppression. The pneumonias may be viral, bacterial/fungal, or mixed. The highest frequency of progression to fatal viral pneumonia has been reported for RSV infections in recently transplanted BMT recipients and myelosuppressed patients with leukemia. Studies have suggested that early therapy for RSV pneumonia with a combination of aerosolized ribavirin and intravenous immunoglobulin may be of benefit. Defining effective prophylactic and therapeutic strategies will be a challenge, given the diversity of viruses, the wide spectrum of immunocompromised patients with varying vulnerability to serious community respiratory virus disease, and the frequent presence of other opportunistic infections and medical problems. A combination of antiviral drugs and immunotherapy may need to be considered for their potential additive effect as well as to prevent the emergence of resistant virus, as occurs during monotherapy for influenza with amantadine or rimantadine. The optimal therapies need to be defined in controlled trials; however, it appears that a favorable response will hinge on the initiation of therapy at an early stage of the respiratory illness.