Respiratory Virus Pneumonia after Hematopoietic Cell Transplantation: Associations Between Viral Load in Bronchoalveolar Lavage, Viral RNA Detection in Serum, and Transplant Outcomes

Campbell, Angela P.; Chien, Jason W.; Kuypers, Jane; Englund, Janet A.; Wald, Anna; Guthrie, Katherine A.; Corey, Lawrence; Boeckh, Michael

BACKGROUND: Few data exist regarding respiratory virus quantitation in lower respiratory samples and detection in serum from hematopoietic cell transplantation (HCT) recipients with respiratory virus-associated pneumonia. METHODS: We retrospectively identified HCT recipients with respiratory syncytial virus (RSV), parainfluenza (PIV), influenza, metapneumovirus (MPV), and coronavirus (CoV) detected in BAL samples, and tested stored BAL and/or serum samples using quantitative PCR. RESULTS: In 85 BAL samples from 82 patients, median viral load in copies/ml for RSV (n=35) was 2.6×10(6), PIV (n=35) 4.9×10(7), influenza (n=9) 6.8×10(5), MPV (n=7) 3.9×10(7), and CoV (n=4) 1.8×10(5). Quantitative viral load was not associated with mechanical ventilation or death. Viral RNA was detected in serum of 6 of 66 patients: 4 of 41 with RSV pneumonia, 1 with influenza B, and 1 with MPV/influenza A/CoV co-infection (influenza A and MPV RNA detected). RSV detection in serum was associated with high viral load in BAL (p=0.05). Detection of viral RNA in serum was significantly associated with death (adjusted RR 1.8, p=0.02). CONCLUSION: Quantitative PCR detects high viral load in BAL samples from HCT recipients with respiratory virus pneumonia. Viral RNA is also detectable in serum of patients with RSV, influenza, and MPV pneumonia, and may correlate with disease severity.