Respiratory virus infection among hematopoietic cell transplant recipients: evidence for asymptomatic parainfluenza virus infection

Abstract

The incidence of respiratory virus infection after hematopoietic cell transplantation (HCT) has probably been underestimated with conventional testing methods in symptomatic patients. This prospective study assessed viral infection episodes by testing weekly respiratory samples collected from HCT recipients, with and without symptoms reported by questionnaire, for 100 days after HCT. Samples were tested by culture and direct fluorescent antibody testing for respiratory syncytial virus (RSV), parainfluenza virus (PIV), and influenza A and B, and by quantitative reverse transcription–polymerase chain reaction for RSV, PIV, influenza A and B, and metapneumovirus (MPV). Of 122 patients, 30 (25%) had 32 infection episodes caused by RSV (5), PIV (17), MPV (6), influenza (3), RSV, or influenza (1). PIV, with a cumulative incidence estimate of 17.9%, was the only virus for which asymptomatic infection was detected. Lower virus copy number in patients with no or one symptom compared with 2 or more symptoms was found for all viruses in all patients (P < .001), with PIV infection having a similar virus-specific comparison (P = .004). Subclinical infection with PIV may help explain why infection-control programs that emphasize symptoms are effective against RSV and influenza but often not against PIV.

Frequency of human metapneumovirus infection in hematopoietic SCT recipients during 3 consecutive years

“…Englund et al 7 observed that 5 of 163 (3.0%) bronchoalveolar (BAL) lavage samples from HSCT recipients with lower respiratory tract disease were tested positive for hMPV. Peck et al 8 observed a 5.8% cumulative incidence of hMPV in a prospective surveillance study in which patients were followed during four winter/spring seasons.…”

Respiratory Viral Detection in the Pediatric Hematopoietic Stem Cell Transplant Population

“…Furthermore, subclinical respiratory viral infection has been documented and is considered transmissible [13][14][15]. A recent study by Campbell et al, looking at clinical outcomes in patients with pre-HSCT viral detection and post-transplant viral detection found no increased mortality with asymptomatic viral detection including those with asymptomatic pre-transplant viral detection but did find increased mortality with symptomatic viral detection including those with symptomatic pre-transplant viral detection [4].…”

Immune modulatory activity of ribavirin for serious human metapneumovirus disease: early i.v. therapy may improve outcomes in immunosuppressed SCT recipients

“…11 Routine use of this highly sensitive diagnostic PCR assay, however, should be approached with caution as in most patients following SCT, the presence of hMPV RNA in nasopharyngeal samples may not represent active viral disease or serve as an indication for antiviral therapy. [1][2][3] hMPV can lead to serious disease in SCT recipients, and intravenous ribavirin appears to be promising therapy that requires further investigation. …”

“…2 The occasional hMPV upper respiratory tract infection often resolves spontaneously and the usual brief illness seldom progresses to the lower respiratory tract. 3 However, in severely immunosuppressed transplant recipients, hMPV may rarely cause life-threatening pulmonary 4,5 and brain infection. 6 Ribavirin disrupts viral purine metabolism and inhibits viral RNA polymerase.…”