The concordance of immunofluorescence (IF) and immunohistochemistry (IHC)
results is a crucial point in routine diagnostic procedures.
This aspect seems to depend on the examined organ. In cardiac transplantation,
comparison of C4d detection by IF and IHC suggests an almost near perfect
agreement (1-3). In lung allografts, only one study compared the reproducibility
of C4d deposition by IF and IHC (4). This study concluded that agreement
of IF-based staining was apparently superior to that of IHC. Given the
different number of biopsy pieces analyzed by the two techniques in the study,
this evidence should be confirmed. The interpretation of IF is hampered by the
autofluorescence of elastic fibers and IHC by strong 3+ staining on the
elastic fibres. Subtle 1+ staining of capillaries is thus hard to discern.
Not surprisingly, overall agreement for IHC and IF among pathologists is sub-optimal.
A multidisciplinary approach seems to be the best way to diagnose AMR.
E.K. Verbeken (Pathologist, UZ/KU Leuven; BE)
References :
1. Chantranuwat C, Qiao JH, Kobashigawa J, Hong L, Shintaku P, Fishbein MC. Immunoperoxidase staining for C4d on paraffin-embedded tissue in cardiac allograft endomyocardial biopsies: comparison to frozen tissue immunofluorescence. Appl Immunohistochem Mol Morphol. 2004; 12: 166-171.
2. Smith R, Brousaides N, Grazette L, Saidman S, Semigran M, Disalvo T, Madsen J, Dec G, Perez-Atayde A, Collins A. C4d deposition in cardiac allografts correlates with alloantibody. J Heart Lung Transplant. 2005; 24: 1202-1210.
3. Miller DV, Roden AC, Gamez JD, Tazelaar HD. Detection of C4d deposition in cardiac allografts: a comparative study of immunofluorescence and immunoperoxidase methods. Arch Pathol Lab Med. 2010; 134: 1679-1684.
4. Roden AC, Maleszewski JJ, Yi ES, Jenkins SM, Gandhi MJ, Scott JP, Aubry MC. Reproducibility of complement 4d deposition by immunofluorescence and immunohistochemistry in lung allograft biopsies. J Heart Lung Transplant. 2014; 33: 1223-1226.
