Date: Monday, June 13, 2016
Session Time: 2:30pm-4:00pm
Presentation Time: 3:06pm-3:18pm
Location: Ballroom B
Background: Microvascular inflammation (MVI), assessed as glomerulitis (g) + peritubular capillaritis (ptc), is associated with T cell mediated (CMR) and antibody mediated (AMR) allograft rejection. It is a key finding in diagnosis of C4d-negative AMR. For that reason it was incorporated into the 2013 update of the Banff classification. There is high inter-observer variability however.
We observed a high proportion of MVI cells in allograft rejection are activated cytotoxic T cells with aggregated perforin-positive granules detectable by immunohistochemistry (IHC). Perforin positive cells are rare in the interstitium and tubules. In this setting the perforin stain is a stain for MVI. We sought to determine whether it could substitute for the calculation of MVI.
Design: Fifty clinically indicated renal allograft biopsies were selected to include various classes of rejection based on the 2013 Banff criteria. Perforin IHC was performed on each biopsy using a mouse monoclonal antibody, and the number of perforin positive cells per 10 high power fields (400X) was counted blindly and recorded.
Results: Table 1. Mean perforin positive cells per 10 high power fields (hpf) in renal transplant biopsies grouped by Banff classification.
|Classification of rejection:||No rejection||CMR 1a||CMR 1b||CMR 2a & 2b||AMR|
|Positive cells per 10 h.p.f.||19.8 +/- 7.1||25.5 +/- 12.8||57.0 +/- 7.7||45.0 +/- 8.4||93.1 +/- 17.2|
Cases of CMR graded at 1B or higher, and cases of AMR had increased perforin counts per unit area over cases with no acute rejection or CMR 1a (p<0.05). Cases of AMR had higher mean perforin counts than patients with either 1B or 2 ACR (p<0.05).
Conclusion: Perforin counts show the same associations with allograft rejection as previously shown for MVI. The perforin count stratifies patients into three risk groups: 1. no rejection and CMR 1a, 2. CMR 1b and 2, and 3. AMR.
Perforin-positive lymphocytes in peritubular capillaries in an allograft biopsy (400X).
CITATION INFORMATION: Rooney M, Ping Z, Samarapungavan D, Hennigar R. An Improved Method for the Evaluation of Microvascular Inflammation in Renal Allograft Biopsies. Am J Transplant. 2016;16 (suppl 3).
To cite this abstract in AMA style:Rooney M, Ping Z, Samarapungavan D, Hennigar R. An Improved Method for the Evaluation of Microvascular Inflammation in Renal Allograft Biopsies. [abstract]. Am J Transplant. 2016; 16 (suppl 3). http://atcmeetingabstracts.com/abstract/an-improved-method-for-the-evaluation-of-microvascular-inflammation-in-renal-allograft-biopsies/. Accessed December 18, 2017.
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