C4d/CD34 double-immunofluorescence staining of renal allograft biopsies for assessing peritubular capillary C4d positivity

Department of Pathology, University of California, San Francisco, San Francisco, CA, USA.
Modern Pathology (Impact Factor: 6.36). 03/2012; 25(3):434-8. DOI: 10.1038/modpathol.2011.168
Source: PubMed

ABSTRACT Immunofluorescence detection of the complement split product C4d along peritubular capillaries in renal allograft biopsies is the mainstay for the diagnosis of antibody-mediated rejection. The extent of peritubular capillary C4d positivity may have significant clinical ramifications; however, peritubular capillary density in the renal cortex is often difficult to assess with single-channel immunofluorescence. In this study, we report a C4d/CD34 double-immunofluorescence staining protocol for renal allograft frozen sections that allows rapid and sensitive detection of C4d positivity, as well as improved accuracy in estimating the C4d-positive fraction of peritubular capillaries. In addition, this method aids in determining whether C4d-positive structures correspond to peritubular capillaries or whether they represent common mimics of peritubular capillaries such as tubular basement membranes. C4d/CD34 double immunofluorescence provides rapid, convenient, and low-cost implementation for laboratories currently utilizing single-channel C4d immunofluorescence.

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    ABSTRACT: OBJECTIVE Evidence supporting an association between complement (C) and type 1 diabetes (T1D) includes the identification of C-fixing islet cell autoantibodies (CF-ICA) and genetic associations with the MHC III C4 region on chromosome 6. Therefore, we investigated whether C activation was present in pancreata from those with or at increased-risk (positive for T1D associated autoantibodies) for T1D.RESEARCH DESIGN AND METHODS Immunohistochemical techniques were used to measure the C degradation product C4d in organ donor pancreata from patients with T1D, type 2 diabetes (T2D), autoantibody positive, and autoantibody negative subjects.RESULTSMedian C4d antigen density differed across the groups (P < 0.0001) and was highest in patients with T1D. C4d immunostaining localized to the blood vessel endothelium and extracellular matrix surrounding blood vessels and exocrine ducts. Receiver Operating Characteristic (ROC) analysis resulted in 81.8% sensitivity and 94.4% specificity for C4d staining.CONCLUSIONS These data suggest that C activation is occurring within pancreata from patients with T1D and C4d may be a biomarker for T1D.
    Diabetes care 09/2013; 36(11). DOI:10.2337/dc13-0203 · 8.57 Impact Factor


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