title: Assessment of the Cylex ImmuKnow cell function assay in pediatric heart transplant patients.
abstract: BACKGROUND
  The Cylex ImmuKnow (Cylex, Columbia, MD) cell function assay (CICFA) is a commercially available test of immune response that purportedly identifies solid organ transplant patients at risk for either acute rejection (AR) or infection. Data on the utility of this test in pediatric heart transplant patients are very limited. This study tested the hypothesis that CICFA is a clinically useful test in this transplant population.
  
  
  METHODS
  All children undergoing heart transplantation at the study center (1989-2006) for whom CICFA levels were obtained were reviewed. The association of CICFA levels with episodes of AR and significant infections was determined.
  
  
  RESULTS
  Among 83 patients (34 girls, 41%), 367 CICFA levels were obtained (median, 4.0; interquartile range [IQR], 2.0-6.0 per patient). There were 26 episodes of AR in 17 patients (20%) and 38 infections in 34 patients (41%). CICFA levels were similar among patients with AR at the time of the CICFA measurement (median, 325 [IQR, 163-480] adenosine triphosphate [ATP] ng/ml) vs patients without AR (median, 330 [IQR, 227-441] ATP ng/ml; p = 0.36). CICFA levels were similar among patients with infections within 1 month of CICFA measurement (median, 295 [IQR, 216-366] ATP ng/ml) and those without infections (median, 330 [IQR, 226-453] ATP ng/ml; p = 0.24).
  
  
  CONCLUSIONS
  The CICFA is not predictive of AR or significant infections in pediatric heart transplant patients. On the basis of the available evidence, this assay cannot be recommended as part of the routine management of pediatric heart transplant patients.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA. jrossano@bcm.tmc.edu
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Rossano
authors.forename: Susan W
authors.initials: SW
authors.lastname: Denfield
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Kim
authors.forename: Jack F
authors.initials: JF
authors.lastname: Price
authors.forename: John L
authors.initials: JL
authors.lastname: Jefferies
authors.forename: Jamie A
authors.initials: JA
authors.lastname: Decker
authors.forename: E O'Brian
authors.initials: EO
authors.lastname: Smith
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Clunie
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Towbin
authors.forename: William J
authors.initials: WJ
authors.lastname: Dreyer
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D015703:Antigens, CD / Q000276:immunology; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology* / Q000276:immunology*; D006331:Heart Diseases / Q000145:classification / Q000601:surgery; D016027:Heart Transplantation / Q000276:immunology / Q000473:pathology / Q000502:physiology*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D007239:Infections / Q000276:immunology / Q000503:physiopathology*; D007518:Isoantibodies / Q000097:blood; D008297:Male; D011183:Postoperative Complications / Q000276:immunology / Q000503:physiopathology; D011237:Predictive Value of Tests; D012189:Retrospective Studies
chemical_list: D015703:Antigens, CD; D007518:Isoantibodies; D000255:Adenosine Triphosphate