Effectiveness of RSVIG prophylaxis and therapy of respiratory syncytial virus in an immunosuppressed animal model

Respiratory syncytial virus (RSV) has emerged as a leading cause of pneumon ia, with high mortality, in bone marrow transplant (BMT) recipients, as wel l as in other profoundly immunocompromised patients, such as myelosuppresse d adults with leukemia. We tested the efficacy of immunoglobulin with high anti-RSV neutralizing antibody levels (RSVIG) for prophylaxis and therapy o f RSV infection in cotton rats undergoing prolonged immunosuppression with cyclophosphamide, These animals experience persistent infection, a model wh ich is similar to the disease seen in post-BMT humans, Both prophylaxis and therapy reduced pulmonary viral replication over 500-fold to nearly undete ctable levels, In animals receiving continual immunosuppression, the use of multiple therapeutic doses of RSVIG was able to prevent rebound viral repl ication, though virus was not completely eliminated.