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

## TL;DR

This study finds that immunosuppressive drugs like sirolimus and low antibody levels increase the risk of RSV infection in hematopoietic cell transplant recipients.

## Contribution

The study identifies clinical and antibody-based risk factors for RSV infection in immunocompromised transplant patients.

## Key findings

- Prophylaxis with sirolimus for GVHD is significantly correlated with increased RSV infection risk.
- Higher neutralizing antibody levels are associated with reduced RSV infection risk.

## Abstract

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.

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.

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.

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.

Two major findings were found from a prospective cohort of hematopoietic cell transplant recipients. (1) There is a significant correlation between immunosuppression for graft-versus-host disease and increased risk for RSV infection post-transplant. (2) There is a significant correlation between lower antibody levels and increased risk for RSV infection post-transplant.