title: Persistent rhinovirus infection in pediatric hematopoietic stem cell transplant recipients with impaired cellular immunity.
abstract: BACKGROUND
  HRV infections are generally self-limiting in healthy subjects, whereas in immunocompromised hosts HRV infections can lead to severe complications and persistent infections. The persistence of HRV shedding could be due to the inefficient immunological control of a single infectious episode.
  
  
  OBJECTIVE
  To investigate the clinical, virologic and immunologic characteristics of pediatric HSCT recipients with HRV-PI infection.
  
  
  METHODS
  During the period 2006-2012, eight hematopoietic stem cell transplant (HSCT) recipients presented with persistent rhinovirus infection (HRV-PI, ≥30 days). Viral load and T-CD4(+), T-CD8(+), B and NK lymphocyte counts at the onset of infection were compared with those of fourteen HSCT recipients with acute HRV infection (HRV-AI, ≤15 days).
  
  
  RESULTS
  The median duration of HRV positivity in patients with HRV-PI was 61 days (range 30-174 days) and phylogenetic analysis showed the persistence of a single HRV type in all patients (100%). In HSCT recipients with HRV-PI, T-CD4(+), T-CD8(+) and NK cell counts at the onset of infection were significantly lower than those observed in recipients with HRV-AI (p<0.01), while B cell counts were similar in the two groups (p= 0.25). A decrease in HRV load was associated with a significant increase in T-CD4(+), T-CD8(+)and NK lymphocyte counts in HRV-PI patients (p<0.01).
  
  
  CONCLUSIONS
  This study suggests a role for cellular immunity in HRV clearance and highlights the importance of its recovery for the control of HRV infection in HSCT recipients.
authors.affiliation: Molecular Virology Unit, Microbiology and Virology Department, Pavia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Piralla
authors.affiliation: Pediatric Hematology-Oncology and Research Laboratories, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zecca
authors.affiliation: Pediatric Hematology-Oncology and Research Laboratories, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Comoli
authors.affiliation: Molecular Virology Unit, Microbiology and Virology Department, Pavia, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Girello
authors.affiliation: Pediatric Hematology-Oncology and Research Laboratories, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Maccario
authors.affiliation: Molecular Virology Unit, Microbiology and Virology Department, Pavia, Italy; Section of Microbiology, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy. Electronic address: f.baldanti@smatteo.pv.it.
authors.forename: Fausto
authors.initials: F
authors.lastname: Baldanti
mesh_terms: D000293:Adolescent; D001402:B-Lymphocytes / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007111:Immunity, Cellular; D016867:Immunocompromised Host; D007223:Infant; D007694:Killer Cells, Natural / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D008969:Molecular Sequence Data; D010850:Picornaviridae Infections / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D010949:Plasma / Q000821:virology; D012229:Rhinovirus / Q000276:immunology / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D066027:Transplant Recipients; D019562:Viral Load
keywords: Cellular immunity; HRV persistent infection; Hematopoietic stem cell transplant recipients; Immunocompromised pediatric patients