title: BK virus infection in pediatric renal transplantation.
abstract: BACKGROUND
  Polyomavirus BK (BKV) is a common complication after renal transplantation and an important cause of graft loss. The purpose of this study was to determine the incidence of BKV infection (viremia) in our population and to describe clinical features, global outcomes, and potential correlations with clinical or epidemiologic factors.
  
  
  METHODS
  This retrospective single-center study included 84 pediatric recipients of kidney transplantation from January 2006 to September 2012. BKV infection screening consisted of periodic determination of decoy cells in urine samples, confirmed by means of quantitative polymerase chain reaction test in blood.
  
  
  RESULTS
  Twenty-two patients (26%) developed BKV viremia. BKV replication appeared early after renal transplantation (median, 2 months). One-third of patients remained asymptomatic, and 27% presented elevated serum creatinine. Immunosuppression was reduced in 90% of patients, and 83% achieved clearance of viremia within 6 months. There was only 1 case of histologically confirmed BKV nephropathy, which evolved to graft loss despite leflunomide, intravenous immunoglobulins, and mycophenolate discontinuation. Risk of BKV viremia was associated with younger age at transplantation (5.9 y vs 10.9 years; P = .001) and cadaveric donor (relative risk, 3.2; P < .05). BKV infection did not affect short-term renal function and graft survival.
  
  
  CONCLUSIONS
  BKV viremia is very common in the pediatric renal transplant population, especially in younger children and in those receiving a kidney from cadaveric donors. It develops in the 1st months after transplantation. Reduction of immunosuppression seems to be a good therapeutic option, with high rates of clearance of the infection, although the only patient with confirmed BKV nephropathy had poor outcome.
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain. Electronic address: alexzarauzasant@gmail.com.
authors: A
authors: A
authors: Zarauza Santoveña
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: C
authors: C
authors: García Meseguer
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: S
authors: S
authors: Martínez Mejía
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: Á
authors: Á
authors: Alonso Melgar
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: C
authors: C
authors: Fernández Camblor
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: M
authors: M
authors: Melgosa Hijosa
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: A
authors: A
authors: Peña Carrión
authors: Servicio de Nefrología Pediátrica, Hospital Universitario La Paz, Madrid, Spain.
authors: L
authors: L
authors: Espinosa Román
mesh_terms: D000367:Age Factors; D001739:BK Virus; D002648:Child; D002675:Child, Preschool; D046148:Donor Selection; D005260:Female; D006085:Graft Survival; D006801:Humans; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D015994:Incidence; D007223:Infant; D007674:Kidney Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D016030:Kidney Transplantation; D008297:Male; D027601:Polyomavirus Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D012189:Retrospective Studies; D014412:Tumor Virus Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D014766:Viremia / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control
chemical_list: D007166:Immunosuppressive Agents