title: Analysis of fatal cases of pandemic influenza A (H1N1) virus infections in pediatric patients with leukemia.
abstract: BACKGROUND
  Pandemic influenza A/H1N1/2009 virus usually causes mild illness in healthy children. Chronic medical conditions are recognized as increasing the risk for complications of influenza virus infection. Although most studies including children with acute leukemia and H1N1 virus have reported no deaths, some anectodal reports with low patient numbers have reported mortality rates as high as 28.5%. Here, we report patients with leukemia and H1N1 virus and review the literature.
  
  
  METHODS
  Medical records of all children with leukemia and H1N1 virus in our institution were reviewed for demographic, clinical, and laboratory data. We also carried out a systematic review of the English-language literature. Among the 24 articles found, only patients with leukemia and pandemic H1N1 infections were reviewed by two independent reviewers.
  
  
  RESULTS
  Eight of 98 children who received chemotherapy for leukemia were diagnosed with pandemic H1N1 infection. One developed pneumonia and acute respiratory distress syndrome (ARDS) and died. Another one developed hemophagocytic lymphohistiocytosis (HLH) and died due to secondary infection during the 6th week of treatment for HLH. In our study, 2 of 8 patients had a fatal course (25%), compared with an overall mortality of 2.5% in the studies retrieved from PubMed (6/232).
  
  
  CONCLUSIONS
  Pandemic H1N1 influenza virus caused mortality in patients with ARDS or HLH; an unexpected finding for pandemic H1N1 (2009) influenza virus. Thus, for children with leukemia and infected with H1N1 virus, short- and long-term complications should be kept in mind during evaluation.
authors.affiliation: Division of Pediatric Hematology, Dr. Behçet Uz Children's Hospital, İzmir, Turkey. yontemyaman@gmail.com
authors.forename: Yaman
authors.initials: Y
authors.lastname: Yöntem
authors.forename: Devrim
authors.initials: D
authors.lastname: Ilker
authors.forename: Oymak
authors.initials: O
authors.lastname: Yeşim
authors.forename: Türedi
authors.initials: T
authors.lastname: Ayşen
authors.forename: Ozek
authors.initials: O
authors.lastname: Gülcihan
authors.forename: Cartı
authors.initials: C
authors.lastname: Özgür
authors.forename: Akçay Ciblak
authors.initials: AC
authors.lastname: Meral
authors.forename: Tatlı Güneş
authors.initials: TG
authors.lastname: Burçak
authors.forename: Demirağ
authors.initials: D
authors.lastname: Bengü
authors.forename: Albudak
authors.initials: A
authors.lastname: Esin
authors.forename: Badur
authors.initials: B
authors.lastname: Selim
authors.forename: Vergin
authors.initials: V
authors.lastname: Canan
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy / Q000453:epidemiology* / Q000821:virology; D015470:Leukemia, Myeloid, Acute / Q000150:complications* / Q000821:virology; D008297:Male; D058873:Pandemics; D011379:Prognosis; D062606:Tertiary Care Centers
chemical_list: D000998:Antiviral Agents