Intro: Development of BKV nephropathy (BKVN) is a significant risk factor for graft loss. Proximate cause of graft loss is commonly attributed to acute/chronic rejection and persistent inflammation is not uncommon following BKVN diagnosis (Menter et al. AJT 2013). Following BKVN clearance, patients may be at risk for subclinical inflammation/rejection due to reduction in immunosuppression. Histopathological changes associated with BKVN clearance have not been described. In this investigation, we evaluated the paired biopsies of patients who underwent a surveillance biopsy following BKVN clearance.

Methods: We studied 15 patients who had a biopsy confirmed BKVN diagnosis with positive immunostain for SV40 and had undergone a surveillance biopsy. We compared the individual Banff scores (0,1,2,3) for inflammation, tubulitis, peritubular capilliritis, transplant glomerulopathy and interstitial fibrosis/tubular atrophy from index biopsies to the follow-up biopsies using a paired T-test.

Results:Mean time for histological clearance of BKVN was 8.6±3.4 months. All follow-up biopsies stained negative for SV40. Mean serum creatinine was not statistically different at follow-up compared to baseline (P=0.9, Fig1). In Figure 2, the bar graphs demonstrate the proportion of patients with a Banff score of 0,1,2 or 3 for each biopsy parameter. Inflammation (P=0.02) and tubulitis (P=0.005) scores decreased significantly with resolution of BKVN.Conclusion: Our findings suggest that resolution of BKVN is associated with a decrease in inflammation & tubulitis. The absence of inflammation & tubulitis in some patients' follow up biopsy suggests that the level of immunosuppression is adequate. Development of non-invasive biomarkers that identify immune quiescent state following BKVN resolution would be of value.

CITATION INFORMATION: Abuhelaiqa E, Salvatore S, Lee J, Lee J, Muthukumar T, Seshan S, Dadhania D. Improvement in Inflammatory Response Follows Clearance of BKVN. Am J Transplant. 2017;17 (suppl 3).

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