title: Epidemiology of infections following haploidentical peripheral blood hematopoietic cell transplantation.
abstract: BACKGROUND
  The use of T-cell replete haploidentical hematopoietic cell transplant (haplo-HCT) has increased substantially since the introduction of post-transplant cyclophosphamide (PTCy) regimens. Limited data exist concerning infectious complications of haplo-HCT utilizing mobilized peripheral blood (PB) hematopoietic cells.
  
  
  METHODS
  This retrospective cohort study included all adult patients at our institution undergoing PB haplo-HCT with PTCy between June 2009 and June 2015. Infections were microbiologically confirmed. Invasive fungal infections (IFI) classified as "proven" or "probable" by standard definitions were included.
  
  
  RESULTS
  In total, 104 patients were identified. Median follow-up was 218 days (range: 6-1576). A total of 322 episodes of infection were recorded. Eighty-nine percent of patients experienced at least one infection. Median time to first infection was 22 days. Patients experiencing at least one bacterial, viral, and IFI were 62%, 72%, and 6%, respectively. The majority (69%) of bacterial infections were caused by enteric organisms. Seven cases of Staphylococcus aureus infection were recorded, with one bacteremia case. Cytomegalovirus (CMV) viremia occurred in 54/71 (76%) at-risk patients at a median time of 24 days. Sixteen (15%) patients developed CMV disease. Nineteen percent (20/104) of patients developed BK polyomavirus-associated cystitis. Six (6%) patients experienced a total of seven IFI. Infection was the primary cause of death for 12% (6/51) of patients and was a secondary cause for 41%.
  
  
  CONCLUSIONS
  In PB haplo-HCT patients, a high incidence of CMV viremia and disease was observed. Infections with enteric bacteria were common. Fungal and staphylococcal infections were uncommon. Further studies are needed to compare infectious complications in haplo-HCT with other transplant modalities.
authors.affiliation: Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Michael
authors.identifier: http://orcid.org/0000-0001-8092-6644
authors.initials: M
authors.lastname: Slade
authors.affiliation: Department of Medicine, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Goldsmith
authors.affiliation: Division of Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Rizwan
authors.initials: R
authors.lastname: Romee
authors.affiliation: Division of Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: DiPersio
authors.affiliation: Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Erik R
authors.initials: ER
authors.lastname: Dubberke
authors.affiliation: Division of Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Westervelt
authors.affiliation: Division of Oncology, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Geoffrey L
authors.initials: GL
authors.lastname: Uy
authors.affiliation: Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lawrence
mesh_terms: D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D003520:Cyclophosphamide / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006086:Graft vs Host Disease / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects* / Q000379:methods; D006801:Humans; D007165:Immunosuppression Therapy / Q000009:adverse effects; D015994:Incidence; D000072742:Invasive Fungal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D019653:Myeloablative Agonists / Q000009:adverse effects* / Q000627:therapeutic use; D012189:Retrospective Studies; D014184:Transplantation, Homologous / Q000009:adverse effects; D014766:Viremia / Q000453:epidemiology / Q000821:virology; D014777:Virus Diseases / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D055815:Young Adult
chemical_list: D019653:Myeloablative Agonists; D003520:Cyclophosphamide
keywords: haploidentical; hematopoietic cell transplant; peripheral blood graft; stem cell transplant