Kidney Week

Abstract: FR-OR135

The Banff Working Group Classification of Polyomavirus Nephropathy: A Validation Study in the Modern Era

Session Information

• Translational and Transplant Pathology
  October 26, 2018 | Location: 6E, San Diego Convention Center
  Abstract Time: 05:06 PM - 05:18 PM

Category: Transplantation

• 1802 Transplantation: Clinical

Authors

• Nickeleit, Volker, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States

Volker Nickeleit, MD

• Dadhania, Darshana, Weill Cornell Medical College, New York, New York, United States

Darshana Dadhania,

• Gasim, Adil H., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States

Adil H. Gasim,

• Davis, Vicki G., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States

Vicki G. Davis,

• Seshan, Surya V., Weill Cornell Medical College, New York, New York, United States

Surya V. Seshan,

• Singh, Harsharan Kaur, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States

Harsharan Kaur Singh,

Background

The Banff multicenter working group on polyomavirus nephropathy (PVN) recently proposed a morphologic, clinically significant PVN classification scheme with three disease classes based on the histologic degree of intra-renal PV replication and the Banff-ci score. Transplant recipients with definitive PVN managed between 1996-2010 were analyzed (JASN 29: 680, 2018).
Aim: To evaluate the validity of the proposed PVN classification in the modern transplant era.

Methods

652 consecutive adult renal allograft recipients transplanted at UNC after 1/1/2009 were enrolled. In patients with definitive PVN, the first diagnostic biopsy (index biopsy) was scored and PVN classes defined. Clinical and histologic data were statistically analyzed following the Banff working group approach (JASN 29: 680, 2018). Biopsies with TCMR (type II/III), ABMR or other severe renal diseases were excluded from some analyses.

Results

PVN affected 57/652 patients (incidence 8.7%; 39 (68%) males; median age 54 years). 2/57 patients were excluded due to recurrent disease at time of index biopsy. PVN class I: 29/55 (53%), class II: 25/55 (45%), class III: 1/55 (2%; small case number in class III precluded further statistical analysis). Class I was diagnosed earlier (median 18 weeks post grafting) than class II (24 weeks). Baseline S-Cr levels before index biopsy were similar between class I and II: class I 1.4 mg/dl, class II 1.3 mg/dl, p=0.823. At index biopsy, class I compared to II had only a minor rise of S-Cr: median % change from baseline, 10% class I, 37% class II, p=0.004. Over 12-month follow-up, class I showed minimal increase in S-Cr levels compared to baseline (+0.2 mg/dl; median change) in contrast to class II (+0.6 mg/dl; p=0.003). In the study cohort, graft failure was rare: overall 3/55 (5%); class I: 2/29 (7%), class II: 1/25 (4%), class III: 0/1 (0%).

Conclusion

The histologic classification of PVN as proposed by the Banff working group also carries clinical significance in the modern era. PVN class I characterizes cases with stable graft function. Overall graft failure rates for this single site are lower (5%) than reported by the Banff working group (30%). The PVN disease classification provides additional clinical information, therefore it should be incorporated into diagnostic and scientific communications.