Background: Studies have shown that borderline rejection (BR) and acute cellular rejection (ACR) often co-occur with antibody-mediated rejection (AMR). We examined the association between interstitial inflammation in patients with histologic features of AMR and mean fluorescence intensity (MFI) of donor specific antibodies (DSA), specifically HLA-DQ.

Methods: We identified for-cause biopsies (2011-17) using pathology department records where the biopsy results either met the Banff 2015 criteria for AMR and/or where the pathologist explicitly diagnosed AMR. Demographic and clinical data, including results of DSA testing, were obtained by retrospective chart review. The cohort was restricted to patients who had DSA testing performed within 30 days of their biopsy. We analyzed the impact of interstitial inflammation (i and t) co-existing with histopathologic evidence of AMR on the presence of DSA against Class I and Class II HLA, specifically HLA-DQ, and DSA MFI.

Results: We identified 75 unique patients whose biopsies showed histopathology consistent with AMR and who had DSA testing performed within 30 days of their biopsy. Of those, 35 patients (46.6%) were explicitly diagnosed by the pathologist as having either BR or ACR. DSA results were positive (>1,000 MFI) in 64% of patients (n=48). Class I DSA was significantly correlated with both i and t scores (Spearman r=0.30, p=0.008, and r=0.30, p=0.01, respectively). Similarly, Class II DSA was significantly correlated with both i and t scores (r=0.35, p=0.002, and r=0.32, p=0.005, respectively). Analysis of HLA-DQ DSA correlation showed similar results to that of Class II. Furthermore, HLA-DQ was significantly associated with both i and t scores (Chi-square trend p=0.008, p=0.027, respectively). A significant negative correlation was found between the absence of BR or ACR (i+t ≤1) and DSA DQ MFI (r= -0.26, p=0.02). Moreover, there was a significant positive correlation between ACR (i≥2 and t≥2) and DSA DQ MFI (r=0.32, p=0.006).

Conclusions: Banff scores for interstitial inflammation in patients with co-existing histopathologic evidence of AMR are significantly correlated with HLA-DQ status, suggesting a higher association with coexistent cellular rejection in these cases.

CITATION INFORMATION: Harris C., Anderson L., Khaim R., Choudhuri J., Shapiro R., Florman S., Salem F., Menon M. Interstitial Inflammation is Correlated with DQ Antibodies in Kidney Transplant Recipients Am J Transplant. 2017;17 (suppl 3).

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