BK Polyomavirus Nephropathy in Kidney Transplantation: Balancing Rejection and Infection.

BK polyomavirus nephropathy (BKVN) and allograft rejection are two closely-associated diseases on opposite ends of the immune scale in kidney transplant recipients. The principle of balancing the immune system remains the mainstay of therapeutic strategy. While patient outcomes can be improved through screening, risk factors identification, and rapid reduction of immunosuppressants, a lack of standard curative therapy is the primary concern during clinical practice. Additionally, difficulty in pathological differential diagnosis and clinicopathology's dissociation pose problems for a definite diagnosis. This article discusses the delicate evaluation needed to optimize immunosuppression and reviews recent advances in molecular diagnosis and immunological therapy for BKVN patients. New biomarkers for BKVN diagnosis are under development. For example, measurement of virus-specific T cell level may play a role in steering immunosuppressants. The development of cellular therapy may provide prevention, even a cure, for BKVN, a complex post-transplant complication.

Symmetric nephromegaly.

We report a lady with bilateral symmetrical xanthogranulomatous pyelonephritis (XPGN) presented with acute kidney injury and sepsis, in which both CT and MRI mimicked an infiltrative disease, except that the infiltration was not very homogenous. Eventually, the pathological diagnosis turned out to be XPGN. Most XPGN were unilateral, and there have been a few publications of bilateral involvement. Moreover, this case lacked typical manifestations, such as renal calculus, contracted renal pelvis, or obstructive nephropathy. This image reminds us that bilateral renal infiltrative disease could not completely exclude the possibility of XPGN, in which the inhomogeneity of the infiltration pattern on CT/MRI may be a clue.

Tacrolimus Blood Level Fluctuation Predisposes to Coexisting BK Virus Nephropathy and Acute Allograft Rejection.

BK virus nephropathy (BKVN) and allograft rejection are two distinct disease entities which occur at opposite ends of the immune spectrum. However, they coexist in renal transplant recipients. Predisposing factors for this coexistence remain elusive. We identified nine biopsy-proven BKVN patients with coexisting acute rejection, and 21 patients with BKVN alone. We retrospectively analyzed the dosage and blood concentrations of immunosuppressants during the 3-month period prior to the renal biopsy between the two patient groups. Compared to the BKVN alone group, renal function was noticeably worse in the coexistence group (p = 0.030). Regarding the dose and average drug level of immunosuppressants, there was no difference between the two groups. Interestingly, the coefficient of variance of tacrolimus trough blood level was noticeably higher during the 3-month period prior to the renal biopsy in the coexistence group (p = 0.010). Our novel findings suggest that a higher variability of tacrolimus trough level may be associated with the coexistence of BKVN and acute rejection. Since the prognosis is poor and the treatment is challenging in patients with coexisting BKVN and acute rejection, transplant clinicians should strive to avoid fluctuations in immunosuppressant drug levels in patients with either one of these two disease entities.

Non-traumatic ocular and periocular hemorrhages in a hypertensive patient under continuous ambulatory peritoneal dialysis and warfarin therapy.

We herein present the first reported case of severe proptosis caused by ocular and periocular hemorrhages in a continuous ambulatory peritoneal dilaysis patient without previous history of trauma. The bleeding tendency caused by uremia and the use of warfarin during uncontrolled high blood pressure were most likely responsible for her ocular and periocular hemorrhages. Appropriate control of blood pressure and adequate self-care education are important for the prevention and treatment of any bleeding complications in uremic patients receiving both maintenance anticoagulation therapy and peritoneal dialysis.