Orthomyxoviral and paramyxoviral infections in transplant patients.

In summary, orthomyxo- and paramyxoviruses cause clinically important infections in transplant patients. Patients often develop lower respiratory tract involvement and sometimes respiratory failure, which almost is uniformly fatal. Bone marrow transplant recipients appear to be at higher risk of severe disease than are solid-organ recipients, but well defined criteria to predict those patients who will be severely affected are not available. Factors associated with more severe disease include the type of viral pathogen, with pneumonia occurring more commonly with RSV and PIV infection, and the degree of immunosuppression of the patient, particularly the pre-engraftment phase in bone marrow transplant recipients. Because mortality is associated with development of pneumonia, prompt diagnosis and studies for concurrent infections are essential. Evaluation of fever and upper respiratory tract symptoms in patients in the peritransplant period should include sampling of nasopharyngeal and throat for virus isolation and antigen detection for respiratory viruses. If patients develop lower respiratory tract symptoms, early bronchoscopy with BAL is indicated. No specific antiviral therapy has proved effective in the treatment of established respiratory viral infections of transplant patients. Aerosolized ribavirin or, in the instance of influenza A virus infection, oral rimantadine might be considered as early therapy to prevent severe lower respiratory disease. Intravenous ribavirin, currently available on a compassionate use basis, might be considered for treating measles virus infection. In patients with lower tract disease due to RSV, the addition of immunoglobulin with high neutralizing antibody titers to RSV or intravenous ribavirin are additional considerations to forestall respiratory failure. Controlled studies of these interventions are needed in transplant patients before their use can be recommended routinely.