Respiratory Syncytial Virus in Hematopoietic Cell Transplant Recipients: Clinical and Humoral Risk Factors for Infection

Background Respiratory syncytial virus (RSV) frequently causes upper respiratory tract infections, lung disease, and mortality in hematopoietic cell transplant (HCT) recipients. Currently, little is understood about what clinical and immunologic factors increase a patient’s risk of infection or are protective against infection in immunocompromised populations. Methods This study analyzed clinical and serologic data from a cohort of HCT recipients followed longitudinally with weekly blood draws and PCR surveillance for respiratory viruses to gain insight into clinical and antibody-based risk factors for RSV infection post-transplant. Serum was analyzed by a plaque reduction neutralization assay to determine neutralizing antibody titers to RSV. Results Sixteen of 471 HCT recipients tested positive for RSV within the first 100 days post-transplant. A multivariate analysis of clinical factors revealed that prophylaxis with sirolimus for graft versus host disease (GVHD) was significantly correlated with increased risk of RSV infection. Moreover, higher levels of neutralizing antibody to RSV were associated with reduced risk for RSV infection, in a time-varying analysis. Conclusions GVHD prophylaxis with sirolimus and low serum neutralizing antibody titers were correlated with increased risk of RSV infection in the early post-transplant period. These results support the role of developing and implementing strategies that boost neutralizing antibody levels to prevent RSV infections in HCT recipients.