Detecting C4d in Liver Allografts: Immunohistochemistry and Immunofluorescence Show Equivalent Staining
Alexis Scherl, Simona Jakab, Gilbert Moeckel, Kisha Mitchell, Dhanpat Jain, Sukru Emre, Marie Robert. Yale University School of Medicine, New Haven, CT
Background: Endothelial deposition of C4d, detected by immunofluorescent staining (IF), is the gold standard for the diagnosis of antibody-mediated rejection (AMR) in renal allografts. In contrast, reliability of C4d stains in liver allografts has yet to be definitively established. The aims of this study are to compare the sensitivity of C4d stains in liver biopsies by IF and immunohistochemistry (IHC) and to correlate endothelial deposition of C4d with results of serologic tests for AMR.
Design: Our database was searched for biopsies of allograft and native livers for evaluation of rejection or chronic/recurrent hepatitis C (HCV). Serial allograft biopsies from individual patients were included. C4d stains were performed by IHC on formalin fixed and by IF on frozen tissue. Positive staining was defined as strong linear endothelial staining. C4d positivity was correlated with tests for donor serum antibodies (DSA), treatment and clinical response.
Results: As in prior studies, endothelial C4d deposition was demonstrated in inflammatory conditions: C4d staining was seen in 3/11 (27%) of native livers biopsied for HCV staging, 3/15 (20%) of allografts with recurrent HCV, and 2/12 (16%) with acute rejection. Comparison of C4d staining by IF and IHC was done for 17 biopsies taken from 10 patients. Staining patterns in portal and sinusoidal endothelium were concordant between methods in 12 of 17 biopsies (71%). DSA tests were performed in 10 patients, with 19 corresponding biopsies; see Table 1.
|9||WEAK POS||N/A||-||Drug injury||+|
|% POS DSA||% STAINING IN POS DSA§||% STAINING IN POS DSA|
|11/19 55%||5/10 50%||6/11 55%|