Background: Polyomavirus nephropathy (PVAN) has a negative impact on renal allograft survival, and its treatment remains controversial. Therapy options include reduction of immunosuppressive drugs and antiviral drugs. Objective: To evaluate the effect of immunosuppression based on mTORi on the follow up of PVAN. Methods: Cross-sectional cohort of 27 renal transplant recipients, with a diagnosis of polyomavirus nephropathy. Initial immunosuppressive regimen based on MPA/tacrolimus was changed to mTOR/steroids at diagnosis, in presence of urine protein/creatinine ratio <0.5 g/l. Patients were monitored by urine cytology, qualitative PCR in peripheral blood, serum creatinine and urinary protein/creatinine ratio. Results: PVAN was suspected 14 ±8 months post transplant, based on the presence of decoy cells in serial urine cytology. At this point, serum creatinine was 1.5 ± 0.6 mg / dL, through levels of tacrolimus was 8.6 ± 3.5 ng/dL. Tacrolimus dose was reduced (through level 6.8 ± 2.8 ng/dL), but because of the persistence of viruria and progression of allograft dysfunction (serum creatinine 2.6 ± 0.8 mg/dL), a biopsy was performed 31 ± 22 months after transplant, with the final diagnosis of PVAN stage 2. Mycophenolate and tacrolimus were withdrawn and immunosuppressive therapy maintained with mTORi (sirolimus or everolimus) plus steroids. No rejection episodes occurred in this series. After a 5 year follow up, 10/27 (37%) grafts were lost due progression of PVAN. Risk factors for graft loss were graft dysfunction at first viruria (1.7 ± 0.7 versus 1.4 ± 0.4 mg / dl, p <0.05) or at biopsy (3.1 ± 0.6 versus 2.3 ± 0.7 mg / dl), compared to patients with a functioning graft after 5 years. In the latter group, renal function remained stable (serum creatinine of 2.0 ± 0.5 mg/dl after 70 months follow-up), with viruria clearance after 16 weeks post converting to mTORi. Conclusion: In this series, the change of immunosuppression to mTORi and prednisone was safe with cleared viruria on average 16 weeks after conversion. In patients with earlier renal biopsy and with better renal function, this strategy preserved the allograft function.
To cite this abstract in AMA style:Esteves A, Camargo L, Ulisses L, Rivelli G, Mazzali M. Therapy with mTOR Inhibitors in Polyomavirus Nephropathy: A Five Year Follow Up [abstract]. Am J Transplant. 2013; 13 (suppl 5). http://atcmeetingabstracts.com/abstract/therapy-with-mtor-inhibitors-in-polyomavirus-nephropathy-a-five-year-follow-up/. Accessed September 23, 2017.
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