Pathological diagnosis of antibody-mediated rejection in renal allograft without c4d staining, how much reliable

Background: C4d as a part of complement activation process is a marker for detectingantibody-mediated rejection (ABMR) and its positivity accompanied by positive donorspecific antibody (DSA) and morphologic view of humoral rejection has been suggested todetect ABMR since 2003.Methods: Forty-one specimens of transplanted kidney biopsies gathered from 2006 to 2008were evaluated for morphological changes on light microscopy and nephro-pathologist madedistinct diagnosis for all of specimens then c4d staining was done for all of them. Theassociation between primary diagnosis without c4d staining and c4d scoring on peritubularcapillaries and glomerular capillaries were evaluated to determine whether morphologicalchanges were enough for distinct diagnosis or not.Results: Acute tubular necrosis (ATN) 27%, Interstitial fibrosis and tubular atrophy (IF&TA)17% and T cell mediated rejection (TCMR) 22% were the commonest diagnosis on lightmicroscopy and 17% of all biopsies had diffuse positive c4d staining. There was not anyreport of ABMR in morphological evaluation while c4d positive staining was seen in somespecimens. It may results from masking of ABMR by other morphological changes such asTCMR and no specific histologic changes for ABMR on light microscopy.Conclusion: We would like to emphasize that c4d staining should be done for all of renalallograft biopsies and pathologists all over the world should consider the probability ofABMR masked by other morphological changes on light microscopic evaluation.

Pathological diagnosis of antibody-mediated rejection in renal allograft without c4d staining, how much reliable Keywords:

Kidney transplantation , Antibody-mediated rejection , c4d