Caracterización clínica de la Nefropatía por Poliomavirus BK en pacientes trasplantados renales / Clinical characterization of Polyomavirus BK nephropathy in kidney transplanted patients

INTRODUCCIÓN. La nefropatía por poliomavirus BK resulta un problema emergente en el trasplante renal, pues contribuye a la pérdida temprana de los injertos renales. OBJETIVO. Caracterizar clínicamente a los pacientes trasplantados renales con nefropatía por poliomavirus BK. MATERIALES Y MÉTODOS. Estudio observacional, descriptivo, realizado en el Hospital de Especialidades Carlos Andrade Marín en el período 2013-2022, se obtuvo una base de datos anonimizada, 479 pacientes trasplantados renales, de estos se identificaron 37 pacientes que corresponde a un 7,7% con nefropatía por poliomavirus BK, se realizó un análisis con el programa estadístico SPSS v26®. RESULTADOS. La población estuvo caracterizada por pacientes del sexo masculino (56,8%), con una edad media de 48,2 años, el donante cadavérico fue el más frecuente (94,5%), la mayor parte del tratamiento de la nefropatía por poliomavirus BK consistió en cambio de micofenolato sódico a everolimus y se mantuvo con 50% de Tacrolimus y Prednisona (40,5%); al valorar el cambio de los valores de creatinina, los niveles más elevados fueros a los 12 meses cuando la pérdida renal fue temprana (p: 0,042), y de la misma manera a los 12 meses, fueron más elevados los niveles de creatinina cuando el diagnóstico histopatológico fue Nefropatía por Poliomavirus Clase 3 (p: 0,01). DISCUSIÓN. La prevalencia de la nefropatía se mantuvo por debajo del 10% reportado a nivel global, la creatinina empeoró en pacientes con pérdida temprana del injerto renal y con una clase patológica avanzada, hecho reportado en la fisiopatología de la enfermedad. CONCLUSIÓN. La pérdida del injerto renal temprano presentó una creatinina más alta que la tardía. Es recomendable un tamizaje adecuado para la detección temprana del virus BK siendo crucial para prevenir el deterioro de la función renal y limitar la posterior pérdida del injerto.

INTRODUCTION: BK polyomavirus nephropathy is emerging as a significant concern in kidney transplantation, as it contributes to the early loss of renal grafts. OBJECTIVE: The aim of this study was to clinically characterize renal transplant recipients with BK polyomavirus nephropathy. MATERIALS AND METHODS: An observational and descriptive study was conducted at Carlos Andrade Marín Specialties Hospital during the period of 2013 to 2022. An anonymized database comprising 479 renal transplant patients was utilized. Among these, 37 patients, constituting 7.7%, were identified with BK polyomavirus nephropathy. Data analysis was performed using the statistical program SPSS v26®. RESULTS: The study population was predominantly composed of male patients (56.8%) with a mean age of 48.2 years. Deceased donors accounted for the majority (94.5%) of cases. The primary approach for managing BK polyomavirus nephropathy involved transitioning from mycophenolate sodium to everolimus, alongside maintaining a regimen of 50% tacrolimus and 40.5% prednisone. When assessing changes in creatinine values, the highest levels were observed at 12 months, coinciding with early renal loss (p: 0.042). Similarly, at the 12-month mark, elevated creatinine levels were associated with a histopathological diagnosis of Polyomavirus nephropathy Class 3 (p: 0.01). DISCUSSION: The prevalence of nephropathy remained below the globally reported threshold of 10%. Creatinine levels worsened in patients experiencing early graft loss and an advanced pathological classification, aligning with established disease pathophysiology. CONCLUSION: Early renal graft loss was associated with higher creatinine levels compared to delayed loss. Adequate screening for early detection of BK virus is recommended, as it plays a crucial role in preventing renal function deterioration and limiting subsequent graft loss.

JCV viruria associates with suboptimal recovery of kidney function three years after living kidney donation / Virúria por JCV se associa a recuperação subótima da função renal três anos após doação renal de doador vivo

Abstract Introduction: Few studies have investigated pre-donation factors that could affect renal recovery after living kidney donation (LKD). We retrospectively investigated the role of John Cunningham virus (JCV) infection and other pre-donation factors on the magnitude of kidney function decline after LKD. Methods: Urine JCV viral loads, glomerular filtration rate, and blood pressure were evaluated in 60 consecutive LK donors before donation. Suboptimal compensatory hypertrophy was defined as an eGFR <60% of the pre-donation eGFR. Results: LKD (40% JCV infected) were followed for 3.2±1.6 years. No association was found between age, gender, and baseline hypertension with 1st, 2nd, 3rd, and 4th years post-donation eGFR <60% of the pre-donation eGFR. Mean eGFR recovery at the 3rd year after donation was lower in JCV infected donors vs non-infected donors (61.8% vs 71.0%, p=0.006). Conclusion: We hypothesized that JCV could shift glomeruli into a hyperfiltration state before nephrectomy, modulating the magnitude of compensatory hypertrophy after donation. Conversely, JCV might curtail the ability of the remaining kidney to promote hyperfiltration. Longer follow up is needed to determine whether JCV viruria ultimately leads to lower eGFR over time or if it is a protective factor for the remaining kidney.

Resumo Introdução Poucos estudos investigaram fatores anteriores à doação que poderiam afetar a recuperação renal após doação renal de doador vivo (LKD, do inglês Living Kidney Donation). Investigamos retrospectivamente o papel da infecção pelo vírus John Cunningham (JCV) e outros fatores de risco pré-doação na magnitude do declínio da função renal após LKD. Métodos: Cargas virais de JCV na urina, taxa de filtração glomerular e pressão arterial foram avaliadas consecutivamente em 60 doadores renais vivos antes da doação. Hipertrofia compensatória subótima foi definida como uma TFGe <60% da TFGe pré-doação. Resultados: LKD (40% infectados pelo JCV) foram acompanhados por 3,2±1,6 anos. Não foi encontrada nenhuma associação entre idade, sexo e hipertensão basal com a TFGe pós-doação no 1º, 2º, 3º e 4º anos <60% da TFGe pré-doação. A recuperação média da TFGe no 3º ano após a doação foi menor em doadores infectados pelo JCV vs doadores não infectados (61,8% vs 71,0%, p=0,006). Conclusão: Levantamos a hipótese de que o JCV pode levar os glomérulos a um estado de hiperfiltração antes da nefrectomia, modulando a magnitude da hipertrofia compensatória após a doação. Por outro lado, o JCV pode limitar a capacidade do rim remanescente de promover a hiperfiltração. É necessário um acompanhamento mais longo para determinar se a virúria por JCV leva, em última instância, a uma menor TFGe ao longo do tempo ou se é um fator de proteção para o rim remanescente.

BK virus nephropathy in a heart transplant recipient / Nefropatia pelo vírus BK em um receptor de transplante cardíaco

Abstract BK virus nephropathy in kidney transplantation is widely recognized as an important cause of graft dysfunction and loss. In the case of transplants of organs other than kidney, BK virus nephropathy in native kidneys has been recognized as a cause of chronic kidney disease, which is related with immunosuppression; however, the diagnosis is usually late because the renal dysfunction is attributed to other causes, such as toxicity by anticalcineurinic drugs, interstitial nephritis due to medications, hemodynamic changes, diabetes, hypertension, etc. We report a case of BK virus nephropathy in a patient who underwent heart transplantation due to peripartum cardiomyopathy. The kidney biopsy reported active chronic tubulointerstitial nephritis associated with late stage polyomavirus nephritis and the blood viral load for BK virus was positive (logarithm 4.5). The immunosuppressive treatment was reduced, and after two years of follow-up, the patient had stable renal function with a serum creatinine of 2.5 mg/dL (GFR of 23.4 mL/min/1.73m2). We recommend that the BK virus be considered as a cause of renal dysfunction in heart transplant recipients, with the aim of detecting its replication in time to reduce immunosuppressive therapy before irreversible compromise of renal function may manifest.

Resumo A nefropatia pelo vírus BK no transplante renal é amplamente reconhecida como uma importante causa de disfunção e perda do enxerto. No caso de transplantes de órgãos que não sejam rins, a nefropatia pelo vírus BK em rins nativos tem sido reconhecida como uma causa de doença renal crônica, que está relacionada com imunossupressão; entretanto, o diagnóstico é geralmente tardio porque a disfunção renal é atribuída a outras causas, tais como toxicidade por drogas anticalcineurínicas, nefrite intersticial devido a medicamentos, alterações hemodinâmicas, diabetes, hipertensão, etc. Relatamos um caso de nefropatia pelo vírus BK em um paciente que foi submetido a transplante cardíaco devido à cardiomiopatia periparto. A biópsia renal relatou nefrite túbulo-intersticial crônica ativa associada à nefrite por poliomavírus em estágio avançado e a carga viral sanguínea para o vírus BK foi positiva (logaritmo 4,5). O tratamento imunossupressor foi reduzido, e após dois anos de acompanhamento, o paciente apresentava função renal estável com creatinina sérica de 2,5 mg/dL (TFG de 23,4 mL/min/1,73m2). Recomendamos que o vírus BK seja considerado como uma causa de disfunção renal em receptores de transplante cardíaco, com o objetivo de detectar sua replicação a tempo de reduzir a terapia imunossupressora antes que um comprometimento irreversível da função renal possa se manifestar.

Cistitis hemorrágica por infección viral en receptores de trasplante hematopoyético haploidéntico: reporte de dos casos / Hemorrhagic cystitis due to viral infection in patients who received hematopoietic haploidentical transplantation: two case reports

Introducción: Las infecciones por virus o la reactivación de virus en estado latente son frecuentes durante el estado de inmunosupresión que sigue al trasplante de progenitores hematopoyéticos, y constituyen una causa importante de complicaciones, como la cistitis hemorrágica, que se caracteriza por disuria, polaquiuria, dolor abdominal y hematuria. La aparición precoz se asocia a la administración de citostáticos como la ciclofosfamida, y el comienzo tardío a la primoinfección o reactivación de virus como citomegalovirus, los adenovirus o los poliomavirus como el BK y el JC. Objetivo: Describir las características clínicas, la evolución y el manejo de la cistitis hemorrágica postrasplante. Casos clínicos: Se presentan dos pacientes con leucemia mieloide aguda que desarrollaron cistitis hemorrágica asociada a infección viral por virus BK y citomegalovirus después del trasplante haploidéntico con ciclofosfamida postrasplante. La cistitis hemorrágica de causa viral después del trasplante hematopoyético en estos pacientes estuvo asociada a una severa inmunosupresión, por lo que constituyó una complicación potencialmente letal. Los dos pacientes presentaron cistitis hemorrágica grado IV y fallecieron a pesar del tratamiento. Conclusiones: El trasplante haploidéntico con la administración de ciclofosfamida postrasplante incrementa la posibilidad de donantes de progenitores hematopoyéticos para los pacientes sin un hermano HLA idéntico pero el mayor nivel de inmunosupresión podría aumentar la incidencia de cistitis hemorrágica de causa viral(AU)

Introduction: Viral infections or latent-virus reactivation are frequent during the immunosuppressed cincition that follows hematopoietic stem-cell transplantation, and an important cause of complications, such as hemorrhagic cystitis, characterized by dysuria, urinary frequency, abdominal pain, and hematuria. The early appearance is associated with the administration of cytostatic drugs such as cyclophosphamide, and the late onset is associated with primary infection or reactivation of viruses such as cytomegalovirus, adenoviruses, or polyomaviruses such as BK and JC. Objective: To describe the clinical characteristics, evolution and management of post-transplant hemorrhagic cystitis. Clinical cases: The cases are presented of two patients with acute myeloid leukemia who developed hemorrhagic cystitis associated with viral infection by BK virus and cytomegalovirus after haploidentical transplantation with post-transplant cyclophosphamide. Viral hemorrhagic cystitis after hematopoietic transplantation in these patients was associated with severe immunosuppression, making it a potentially lethal complication. Both patients presented grade IV hemorrhagic cystitis and died despite treatment. Conclusions: Haploidentical transplantation with the of post-transplant cyclophosphamide administration increases the possibility for donors of hematopoietic progenitor cells to patients without an identical HLA match, but the higher level of immunosuppression could increase the incidence of viral hemorrhagic cystitis(AU)

Human polyomavirus infection: Cytological and molecular diagnosis / Infecção pelo poliomavírus humano: diagnóstico citológico e molecular

Summary Few studies directly compare urinary cytology with molecular methods for detecting BK and JC polyomaviruses. Reactivation of BKV infection is the main risk factor for the development of nephropathy in immunocompromised individuals. The limitation of the cytological method can be attributed to the stage where the infected cell does not have specific and sufficient morphological characteristics for a conclusive diagnosis and can be easily interpreted as degenerative alteration. Moreover, morphologically, it is not possible to differentiate the two types of viruses. Polymerase chain reaction (PCR), not only is a sensitive method, but also allows differentiation of viral types without quantification, and therefore is not indicative of nephropathy. According to the American Society of Nephrology, real-time PCR would be the gold standard to indicate nephropathy because it allows quantifying the number of viral copies.

Resumo Poucos estudos comparam diretamente a citologia urinária com métodos moleculares para detecção de poliomavírus BK e JC. A reativação da infecção por BKV é o principal fator de risco para o desenvolvimento de nefropatia em indivíduos imunocomprometidos. A limitação do método citológico pode ser atribuída ao estágio em que a célula infectada não possui características morfológicas específicas e suficientes para um diagnóstico conclusivo, podendo ser facilmente interpretada como alteração degenerativa. Além do mais, morfologicamente, não é possível diferenciar os dois tipos virais. A reação em cadeia pela polimerase (PCR), além de ser um método sensível, permite diferenciar os tipos virais sem quantificá-los, não sendo, portanto, indicativa de nefropatia. Segundo a American Society of Nephrology, a PCR em tempo real seria o padrão-ouro para indicar nefropatia, pois permite quantificar o número de cópias virais.

Poliomavirus en sistema nervioso central, una aproximación imagenológica / Polyomaviruses and central nervous system disease

The polyomavirus are a family of opportunistic virus, which belongs to the JC virus whose primary manifestation is the Progressive Multifocal Leukoencephalopathy and neuronopathy of granulosa cells. Recently given the use of PCR for BK virus in transplant patients have also been described CNS pathologies in relation to this, and most frequent encephalitis and leukoencephalopathy. Each entity has a compatible clinical and genetic testing have allowed a diagnosis of high specificity, however the RNM is the great diagnostic pillar in these pathologies, allowing differentiate the different entities, the progression of lesions and response to treatment, especially in cases where it is indicated antiretroviral therapy, as gadolinium enhancement and mass effect may suggest Syndrome Immune and worse prognosis.

Los Poliomavirus son una familia de virus oportunistas, al cual pertenece el virus JC cuya principal manifestación es la Leucoencefalopatía Multifocal Progresiva y la Neuronopatía de Células Granulosas. Recientemente, dada la utilización de PCR para virus BK en LCR en pacientes trasplantados, también se han descrito patologías de SNC en relación a éste, siendo lo más frecuente la Encefalitis y la Leucoencefalopatía. Cada entidad tiene un contexto clínico compatible y las pruebas genéticas han permitido un diagnóstico de alta especificidad, sin embargo, la RNM es el gran pilar diagnóstico en estas patologías, permitiendo diferenciar las distintas entidades, la progresión de las lesiones y la respuesta a tratamiento, especialmente en los casos en que está indicado la terapia antirretroviral, pues la captación de gadolinio y el efecto de masa pueden sugerir un Síndrome de Reconstitución Inmune y peor pronóstico.

Screening for BK virus nephropathy in kidney transplant recipients: comparison of diagnostic tests / Desempenho de métodos diagnósticos no rastreio de nefropatia pelo vírus BK em pacientes transplantados renais

Abstract Urine cytology and qPCR in blood and urine are commonly used to screen renal transplant recipients for polyomavirus-associated nephropathy (PVAN). Few studies, however, have directly compared these two diagnostic tests, in terms of their performance to predict PVAN. This was a systematic review in which adult (≥ 18 years old) renal transplant recipients were studied. A structured Pubmed search was used to identify studies comparing urine cytology and/or qPCR in urine and plasma samples for detecting PVAN with renal biopsy as the gold standard for diagnosis. From 707 potential papers, there were only twelve articles that matched the inclusion criteria and were analyzed in detail. Among 1694 renal transplant recipients that were included in the review, there were 115 (6.8%) patients with presumptive PVAN and 57 (3.4%) PVAN confirmed. In this systematic review, the qPCR in plasma had better performance for PVAN compared to urine cytopathology.

Resumo A citologia urinária e a reação da cadeia da polimerase em tempo real (qPCR) em amostras de sangue e/ou urina são comumente utilizados para rastrear nefropatia associada ao polyomavirus (PVAN), em pacientes transplantados renais. Entretanto, poucos estudos comparam diretamente esses testes diagnósticos quanto ao desempenho para predizer esta complicação. Aqui realizamos uma revisão sistemática na qual foram estudados pacientes transplantados renais adultos (≥ 18 anos). Uma pesquisa estruturada Pubmed foi utilizada para identificar estudos comparando citologia urinária e/ou qPCR em amostras de urina e plasma para detectar PVAN, utilizando a biópsia renal como padrão-ouro para o diagnóstico. Dentre os 707 artigos em potencial, apenas 12 atendiam aos critérios de inclusão e foram analisados em maior detalhe. Foram incluídos 1694 pacientes transplantados renais, entre os quais 115 (6,8%) classificados com PVAN presuntivo e 57 (3,4%) PVAN confirmado. Nessa revisão sistemática, o qPCR no plasma tive melhor desempenho para PVAN em comparação com citopatologia urinária.

Detección de polyomavirus BK y JC en extractos leucocitarios de sangre periférica de pacientes con infección por VIH del área norte de Santiago / BK and JC polyomavirus detection in leukocyte extracts of peripheral blood samples of HIV+ patients from the north area of Santiago

Introducción: Polyomavirus BK (BKPyV) y JC (JCPyV) son patógenos persistentes con capacidad de reactivación en inmunocomprometidos, afectando principalmente el sistema urinario y el sistema nervioso central, respectivamente. No existen estudios chilenos en población infectada por VIH. Objetivo: Detectar la presencia de BKPyV y JCPyV en muestras de sangre de pacientes adultos, chilenos, con infección por VIH y correlacionar los resultados con variables clínicas. Materiales y Métodos: Analizamos 96 muestras de extractos leucocitarios de pacientes del área norte de Santiago. El genoma viral se detectó mediante RPC en tiempo real. Para el análisis estadístico se utilizó las pruebas chi-cuadrado de Pearson y Mann-Whitney, considerando significativo un valor de p < 0,05. Resultados: 33% de las muestras resultaron positivas para BKPyV y se encontró una correlación significativa entre la presencia de genoma de BKPyV y la ausencia de carga viral de VIH. Se evidenció la necesidad de considerar más de un blanco de amplificación del genoma de BKPyV. Todas las muestras fueron negativas para JCPyV. Discusión: La prevalencia de BKPyV en pacientes chilenos con infección por VIH es superior a la informada en la mayoría de los reportes internacionales. Se requiere estudios que evalúen la interacción entre ambos virus. Estos pacientes deberían ser sometidos a controles urológicos y nefrológicos periódicos.

Introduction: Polyomavirus BK (BKPyV) and JC (JCPyV) are persistent pathogens able to reactivate in im-munocompromised patients, involving mostly urinary and central nervous system. There are no Chilean studies in HIV positive patients. Objective: To detect BKPyV and JCPyV in blood of Chilean HIV positive adult patients and to correlate these results with clinical-related variables. Materials and Methods: 96 stored blood samples from HIV patients belonging to the north area of Santiago were analyzed. Viral genomes of both viruses were detected by real-time PCR. For statistical analysis, chi-square (Pearson) and Mann-Whitney tests were used and p-values < 0.05 were considered significant. Results: 33% of the samples were positive for BKPyV and a significant correlation was found between the presence of BKPyV genome and the absence of detectable HIV viral load. We demonstrated the need to consider more than one amplification target to detect the BKPyV genome. All the samples were negative for JCPyV genome. Discussion: BKPyV prevalence in Chilean HIV patients is higher than most of international studies. New studies regarding the interaction between both viruses are required. These patients should undergo periodic evaluations by urologist and nephrologist.

Neuropatía por virus BK post trasplante renal diagnostico y seguimiento por PCR en tiempo real / BK virus nephropathy after renal transplantation: Diagnosis and prognosis by real time PCR

La nefropatía producida por el virus BK puede llevar a la pérdida del trasplante renal. El diagnóstico etiológico es importante debido a que la clínica no permite diferenciar entre nefropatía por virus BK y rechazo agudo, en donde los tratamientos de estas dos entidades son diametralmente opuestos. El desarrollo reciente de métodos moleculares muy sensibles y específicos como PCR y PCR en tiempo real para virus BK permiten un diagnóstico de certeza en forma rápida y cuantificar la carga viral presente. El diagnóstico de nefropatía por virus BK se realiza por inmunohistoquímica en una biopsia renal, pero dada la naturaleza multifocal de las lesiones, la sensibilidad no siempre es del 100%. Los nuevos métodos de PCR para detectar virus BK en sangre y orina contribuyen al diagnóstico de nefropatía de una manera más normatizada y menos invasiva. Más aún, la cuantificación del virus BK en sangre por PCR en tiempo real, ha demostrado ser útil en el diagnóstico y monitoreo de esta enfermedad. En este trabajo se presenta el caso de una paciente transplantada renal con nefropatía por virus BK y el desarrollo de un método de PCR en tiempo real para la detección de virus BK en sangre y orina. Esta nueva metodología confirmó el diagnóstico de nefropatía por virus BK lo que permitió un cambio en el esquema de inmunosupresión y la instauración de un tratamiento que pudo ser monitorizado utilizando la carga viral.

BK virus nephropathy may lead to kidney transplant failure. BK infection and acute rejection are clinically undistinguishable, therefore diagnosis of these entities is critical to establish the correct treatment. The new molecular methods using PCR and real time PCR have significantly contributed to the rapid and sensitive diagnosis of BK virus. Furthermore, viral load determination in plasma has significantly been associated with BK virus nephropathy. Definite diagnosis of nephropathy requires renal biopsy, although due to the multifocal nature of the disease sensitivity may be less than 100%. BK detection in blood and urine by PCR has contributed to the diagnosis of nephropathy in a more standardized and less invasive way. Recently, quantification of BK virus in plasma has been used for the diagnosis and monitoring of this disease. In the present study, we describe the validation of a real time PCR method for BK virus detection in plasma and urine and its application for diagnosis and monitoring in a renal transplant patient with nephropathy.

Self-quenched Probe Fluorescent Quantitative PCR Detective Method for Polyoma virus BK:Its Development and Clinical Application / 中华医院感染学杂志

OBJECTIVE To develop a new rapid method of real time fluorescence quantitative Polymerase chain reaction(PCR) to detect Polyoma virus BK(BKV) with high sensitivity,specificity,stability and lower price using the self-quenched probe.METHODS DNA segment of BKV was cloned into the vector pGEM-11Zf.The recombinant vector pGEM-11Zf-BK was used as standard template.The self quenched probe was designed according to the cloned gene sequence.The PCR reaction system was optimized and the method established was evaluated.RESULTS Restriction maps showed that the structure of recombinant plasmid pGEM-11Zf-BK was the same as expected.Methodology analysis suggested that self-quenched probe fluorescent quantitative PCR detective method of BKV be successfully established with high sensitivity,specificity and accuracy.CONCLUSIONS The self-quenched probe fluorescence quantitative PCR detective method for BKV has been developed successfully with high sensitivity,specificity and accuracy.