Infections à BK virus en transplantation rénale

Treatment of BK virus with a stepwise immunosuppression reduction and intravenous immunoglobulin in pediatric kidney transplant

BACKGROUND

BKV and BKVN are common in pediatric kidney transplant, but there is limited data on treatment approaches. Our objective was to study the prevalence of BKV and BKVN utilizing only plasma qPCR and report treatment outcomes with stepwise IR and IVIG.

METHODS

A retrospective study of all pediatric kidney transplants from 2013 to 2020. Excluded patients >21 years at transplant and immediate graft failure. Surveillance was conducted using only plasma BK qPCR at 1, 3, 6, 9, 12, 18, and 24 months and annually. BKV defined as ≥250 copies/ml and resolution as <250 copies/ml. Presumed BKVN as >10 000 copies/ml despite IR; and BKVN if confirmed on histology.

RESULTS

Fifty-six patients were included in the study; 20 (35.7%) had BKV. BKV was associated with longer duration of stent, 40 vs. 33.5 days (p = .004). Two patients (3.5%) had confirmed, and 2(3.5%) had presumed BKVN. The first-line treatment was IR in 100% of patients. BKVN confirmed and presumed received IVIG every month for six doses. Viral resolution was achieved in 70%, and no difference was noted in estimated glomerular filtration rate between BKV and non-BKV group (p = .438). There were no rejection episodes, and graft survival was 100% over median follow-up of 3 years.

CONCLUSIONS

Plasma qPCR alone is adequate for screening and monitoring treatment of BKV and BKVN. A stepwise IR and IVIG resulted in BKV resolution in the majority of patients. Larger studies are required to study the role of IVIG in the treatment of BKVN.

Nefritis tubulointersticial aguda. Revisión bibliográfica

La nefritis tubulointersticial aguda hace referencia a un tipo de daño renal que afecta principalmente el intersticio y ocasiona la lesión renal aguda, potencialmente reversible. Su curso puede ser subclínico, con deterioro progresivo hasta evolucionar hacia la insuficiencia renal crónica. La nefritis tubulointersticial aguda tiene múltiples etiologías, las más frecuentes son los medicamentos, productos herbales, las infecciones y las enfermedades autoinmunes. Las principales manifestaciones clínicas son la poliuria, polaquiuria, nocturia, dolor lumbar, microhematuria y leucocituria, aunque puede ser totalmente asintomática. El tratamiento depende de la causa de base y los esteroides juegan un papel importante cuando la condición es de origen medicamentoso o autoinmune. El pronóstico generalmente es bueno, si el problema se identifica de forma oportuna y se trata adecuadamente.

Successful Treatment for BK Virus Nephropathy by Leflunomide in a Kidney Transplant Patient: A Case Report

INTRODUCTION

The immunosuppressant agents in kidney transplantation (KT) may lead to various complications such as opportunistic infections and malignancies. BK virus associated nephropathy is a significant complication following KT, and it can result in graft failure. BK virus causes tubulointerstitial nephritis, ureter stenosis, and even graft failure in KT recipients with impaired immune system. We described a 63-year-old woman, who was a hepatitis C carrier and on dialysis for 22 years before KT, who received cadaveric-donor KT 2 years previously. She reported decreasing urine output and general weakness. The serum creatinine level was slightly increased from 2.94 to 4.38 mg/dL.

METHODS

Immunosuppressant medications including prednisolone, everolimus, cyclosporin, and mycophenolate sodium were continued as maintenance therapy post KT. Kidney biopsy was performed due to deterioration of graft function.

RESULTS

The kidney biopsy showed consistent results with early-stage polyomavirus nephropathy, characterized by focal viral cytopathic changes with positive immunohistochemical signals and mesangial proliferative glomerulonephritis, immune-complex-mediated (Fig 1 and Fig 2). Negative C4d staining at peritubular capillary was reported. The dosage of mycophenolate sodium was tapered from 720 to 360 mg daily and that of everolimus increased from 0.5 to 1.0 mg daily due to BK viral infection with BK nephropathy. The serum creatinine level was 2.75 mg/dL after treatment.

CONCLUSION

Early detection of BK nephropathy and decreasing immunosuppressant agents are the mainstay of treatment. Substituting leflunomide for mycophenolate sodium and increasing dosage of everolimus has been proposed to solve BK nephropathy. We presented that the use of leflunomide in such situation is in a timely manner.

Prise en charge du transplanté rénal en réanimation

La transplantation rénale est la thérapeutique de choix de l’insuffisance rénale chronique au stade ultime, son usage est de plus en plus large. Les progrès réalisés dans les traitements immunosuppresseurs ont permis une amélioration de la durée de vie du greffon, mais au prix d’une augmentation des complications cardiovasculaires et infectieuses. Environ 5 % des transplantés rénaux présentent des complications sévères qui nécessitent une prise en charge intensive. Elles sont principalement de cause infectieuse et dominées par la défaillance respiratoire aiguë. L’insuffisance rénale aiguë est commune, elle affecte la fonction du greffon à court et long termes. La prise en charge en réanimation de ces complications doit prendre en compte le terrain particulier du transplanté rénal et les effets délétères de l’immunosuppression, condition nécessaire à une amélioration de la mortalité qui reste à plus de 30 %.

Polyomavirus Nephropathy: Ten-Year Experience

BACKGROUND

Polyomavirus nephropathy (BKVN) is an important cause of chronic allograft dysfunction (CAD). Recipient determinants (male sex, white race, and older age), deceased donation, high-dose immunosuppression, diabetes, delayed graft function (DGF), cytomegalovirus infection, and acute rejection (AR) are risk factors. Reducing immunosuppression is the best strategy in BKVN. The objective of our study was to evaluate CAD progression after therapeutic strategies in BKVN and risk factors for graft loss (GL).

METHODS

Retrospective analysis of 23 biopsies, from patients with CAD and histological evidence of BKVN, conducted over a period of 10 years. Glomerular filtration rate was <30 mL/min in 16 patients at the time of the BKVN diagnosis.

RESULTS

BKVN was histologically diagnosed in 23 recipients (19 men, 4 women). All patients were white, with age of 51.2 ± 12.1 years (6 patients, age >60 years), and 22 had a deceased donor. Diabetes affected 4 patients, DGF occurred in 3, cytomegalovirus infection in 2, and AR in 15. All patients were medicated with calcineurin inhibitors (CNI) (95.7% tacrolimus) and corticoids, and 16 also received an antimetabolite. One year after antimetabolite reduction/discontinuation and/or CNI reduction/switching and/or antiviral agents, graft function was decreased in 11 patients, increased/stabilized in 10, and unknown in 2. GL occurred in 9 patients. Older age (hazard ratio, 1.76; 95% confidence interval, 0.94-3.28) and DGF (hazard ratio, 2.60; 95% confidence interval, 0.54-12.64) were the main risk factors for GL. The lower GFR at the time of the BKVN diagnosis was associated with an increased risk of initiation of dialysis.

CONCLUSIONS

GL occurred in 39.1% of patients with BKVN and DGF; older age and lower GFR at the time of diagnosis were important risk factors. Early diagnosis of BKVN is essential to prevent GL.