Mortality rates of human metapneumovirus and respiratory syncytial virus lower respiratory tract infections in hematopoietic cell transplantation recipients

Abstract

Human metapneumovirus (HMPV), a common respiratory virus, can cause severe disease in pre- and post-hematopoietic cell transplantation (HCT) recipients. We conducted a retrospective cohort analysis in HCT patients with HMPV (n = 23) or respiratory syncytial virus (n = 23) detected in bronchoalveolar lavage samples by reverse transcription PCR between 2006 and 2011 to determine disease characteristics and factors associated with outcome. Mortality rates at 100 days were 43% for both HMPV and respiratory syncytial virus lower respiratory tract disease. Steroid therapy, oxygen requirement >2 L or mechanical ventilation, and bone marrow as cell source were significant risk factors for overall and virus-related mortality in multivariable models, whereas the virus type was not. The presence of centrilobular/nodular radiographic infiltrates was a possible protective factor for mechanical ventilation. Thus, HMPV lower respiratory tract disease is associated with high mortality in HCT recipients. Earlier detection in combination with new antiviral therapy is needed to reduce mortality among HCT recipients.

Keywords: Hematopoietic stem cell transplant; Human metapneumovirus; Immunocompromised; Pneumonia; Respiratory syncytial virus.

Figure 1

(A) RT-PCR results on nasal washes (X) sampled within 11 days before or after the positive BAL. Negative nasal washes were found in five patients with HMPV LRTD, whereas all patients with RSV LRTD had at least one positive nasal wash. Negative nasal washes were found in patients with lower BAL viral load. (B) RT-PCR results on sera (X) sampled within 11 days before or after the positive BAL. One patient with HMPV LRTD had two positive sera (HMPV patient three), whereas two patients with RSV LRTD had positive sera (RSV patients two and seven). All three patients with positive sera had a high BAL viral load and died.

Figure 2

Kaplan-Meier survival estimates for (A) RSV and HMPV LRTD and (B) RSV or HMPV LRTD according to steroid dose. (C) HMPV LRTD treated with ribavirin and untreated.