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Medline ® Abstract for Reference 31

of 'Liver transplantation: Diagnosis of acute cellular rejection'

Noninvasive diagnosis of acute cellular rejection in liver transplant recipients: a proteomic signature validated by enzyme-linked immunosorbent assay.
Massoud O, Heimbach J, Viker K, Krishnan A, Poterucha J, Sanchez W, Watt K, Wiesner R, Charlton M
Liver Transpl. 2011;17(6):723.
The diagnosis of acute cellular rejection (ACR) requires liver biopsy with its attendant expense and risk. Our first aim was to prospectively determine in an exploratory analysis whether there is a serum proteome signature associated with histologically confirmed ACR. Our second aim was to use simpler and faster enzyme-linked immunosorbent assay (ELISA)-based assays for proteins identified as differentially abundant in the proteomic analysis to identify patients with ACR in a separate validation cohort. We used sequential high-abundance protein depletion and isobaric tag for relative and absolute quantitation liquid chromatography-tandem mass spectrometry to characterize the serum proteome in serum samples of patients with or without ACR. Seven of the 41 proteins identified as differentially abundant [serum amyloid A, complement component 4 (C4), fibrinogen, complement component 1q (C1q), complement component 3, heat shock protein 60 (HSP60), and HSP70]could be measured with ELISA-based assays in a validation cohort consisting of patients with ACR (n = 25) and patients without ACR (n = 21). The mean alanine aminotransferase (ALT) levels in patients with ACR and in patients without ACR were 198±27 and 153±34 U/L, respectively. Among the 7 proteins for which ELISA assays wereavailable, C4 and C1q were both independent predictors of ACR. C4 had the greatest predictivity for differentiating patients with or without ACR. A C4 level≤0.31 g/L had a sensitivity of 97%, a specificity of 62%, a positive predictive value of 74%, and a negative predictive value of 94%. A C4 level≤0.31 g/L and an ALT level≥70 IU/mL together had a sensitivity of 96%, a specificity of 81%, a positive predictive value of 86%, and a negative predictive value of 94%. In summary, in this exploratory analysis, serum C4 and ALT levels were highly predictive of ACR in liver transplant recipients. Confirmation in a prospective, larger, and diverse population is needed.
Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, USA.