Early diagnosis of PV nephropathy(PyVAN) leads to overall improvements in the short term but sclerosing sequelae and risk for rejection (mainly antibody mediated) contribute to poorer long term outcomes. Description of late histological changes and clinical correlates after the diagnosis of PyVAN are not available.

We evaluated 206 biopsies (Bx) from 71 patients, followed for 3.09y (±1.46) after immunosuppression(IS) reduction. The PyV clinicopathological status (PyVCPS) was determined with each biopsy using viral load dynamics, serum creatinine, SV40+ and rejection. The 1^st and 2^nd Bx corresponded in >60% to the 4 most common PyVCPS, however, 47 PyVCPS combinations occurred in the complete cohort.

Presumptive PyVAN (persistent BK viremia), clinically similar to definite PyVAN (SV40+ in the Bx), occurred in 1st and later Bx (28.2% and 12.5%, respectively). In the 1^st Bx inflammation in SV40+ areas was common (94.1%), with plasma cells in 53%; both increased in the 2^nd and 3^rd Bx and plasma cells correlated with decreasing viremia (p=.002). Inflammation overall, decreased with time, except with acute rejection. Two patients displayed monoclonal plasma cells in tissue and serum M peaks during the infection. Complete viral clearance occurred in 60% of patients (at a mean of 28weeks). Rejection increased the risk for graft loss and overall occurred in 38% of patients (>50% AMR). Incidence of acute rejection was 28% in the 2nd Bx, increasing to 50% subsequently. Graft loss occurred in 15.4% of patients (0.8- 5.3y after PyVAN diagnosis). None of the individual clinical, histological or demographic parameters predicted graft loss or viral clearance, but with lower peak viremia clearance occurred faster (p=.0026).

This study describes the histological evolution of PyVAN and corresponding clinicopathological correlations. Although the pathological features overall reflect the viral and immunological interactions at each time point, the PyVAN course remains difficult to predict based on any single feature due to its variable and multifactorial course. The dynamic nature of PyVAN requires careful personalized adjustment of treatment that can only be achieved with determination of the PyVCPS (clinical and Bx findings) at relevant points of the disease evolution.

CITATION INFORMATION: Drachenberg C, Papadimitriou J, Ugarte R, Mavanur M, Thomas B, Cangro C, Costa N, Weir M, Haririan A. Repeat Biopsies After the Diagnosis of BK Virus Associated Nephropathy: Importance of Integrating Clinical and Pathological Findings. Am J Transplant. 2017;17 (suppl 3).

« Back to 2017 American Transplant Congress