Tricodisplasia espinulosa asociada a leucemia linfoblástica aguda en edad pediátrica: revisión de la literatura a propósito de un caso / Trichodysplasia spinulosa associated with acute lymphoblastic leukemia in pediatric age: review of the literature regarding a case

La tricodisplasia espinulosa es una patología viral infrecuente causada por un tipo de poliomavirus, el cual se da siempre en contexto de inmunosupresión. Existen reportes que estiman una seroprevalencia en adultos de 70%, y hasta 90% en inmu-nocomprometidos. El cuadro clínico se caracteriza por pápulas color piel hiperqueratósicas en zonas centro faciales, orejas y tronco, asintomáticas o con prurito escaso. Existen métodos de confirmación diagnóstica como PCR o test de Elisa, que no se encuentran disponibles en Chile. Por lo tanto, en nuestro contexto el estudio histopatológico es fun-damental, dada su accesibilidad y que los hallazgos de la biopsia son característicos. El manejo debe siempre considerar, de ser posible, disminuir la in-munosupresión del paciente. Otras medidas son: extracción manual de las lesiones y aplicación de cidofovir o valganciclovir tópicos

Trichodysplasia spinulosa is an infrequent viral pathology caused by a type of polyomavirus, which always occurs in context of immunosuppression. There are reports that estimate sero-prevalence in adults of 70%, and 90% in immunocompromised. Patients have numerous, mildly pruritic, folliculocentric, flesh-colored to pink papules with central keratinaceous spines. There are methods of diagnostic confirmation such as PCR or Elisa test, not available in Chile. The-refore, in our context the histopathological study is fundamental because biopsy findings are cha-racteristic. Management should always consider, if possible, decrease the immunosuppression of the patient. Other measures consist of manual extraction and cidofovir or topical valganciclovir.

Virus polioma en carcinoma de células de Merkel / Polyoma virus in Merkel cell carcinoma

Introducción: El carcinoma de células de Merkel (MCC) es un tumor cutáneo maligno agresivo y de mal pronóstico. La incidencia es mayor en adultos hombres, caucásicos, con edad promedio de 70 años. Feng et al, lograron aislar un nuevo virus en muestras de este tumor, que denominaron virus polioma de células de Merkel (MCPyV). Se ha intentado establecer una relación causal entre el virus y MCC. El virus está integrado al genoma y produciría mutaciones específicas. En muestras de MCC, se ha detectado expresión de oncoproteinas virales (antígenos T) que promueven la replicación viral y tumorogénesis

Introduction: Merkel cell carcinoma (MCC) is an aggressive malignant cutaneous tumor with poor prognosis. Most cases affect elder patient with an average of 70 years of age. Feng et al isolated a new virus, the Merkel cell carcinoma polyoma virus (MCPyV). A causal relationship between MCPyV y MCC has been established. The virus is integrated in the genome and pro-duces specific mutations. MCC samples show ex-pression of viral oncoproteins (T antigens) that promote viral replication and tumorogenesis.

Evaluation of the predisposition and clinical impact of BK virus replication in kidney transplant patients

ABSTRACT The BK virus (BKV) produces a subclinical kidney infection in immunocompetent individuals. However, viremia may occur in kidney transplant patients with ongoing immunosuppression. BKV-associated nephropathy (BKVN) has no specific treatment and is a leading cause of organ transplant loss. In this study, we evaluated the predisposition and the clinical impact of BKV replication in kidney transplant patients during post-transplant monitoring in a reference institution in Brazil. Demographic, clinical and laboratory data generated during routine outpatient follow-up were retrospectively collected. BK viremia was investigated using real-time polymerase chain reaction. Of the 553 participants, 7.4% (n = 41) presented BKV replication. Of these, 16 (39%) lost their kidney graft and interstitial nephritis was identified on kidney biopsy in 50% of the cases. Among the evaluated variables, only the use of the immunosuppressant mycophenolate sodium was identified as a risk factor for viremia (OR 7.96; 95% CI 2.35 to 26.98). The graft survival estimate in BKV-positive patients was significantly reduced (24.8% vs. 85.6%) after 10 years of transplantation. We concluded that defining predisposing factors remains an important challenge for the prevention and control of BKV activity following kidney transplantation, especially considering the development of BKVN and its strong effect on graft maintenance.

JC polyomavirus infection in candidates for kidney transplantation living in the Brazilian Amazon Region

This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a 173 bp region of the gene encoding the T antigen of the BKV and JCV. JCV and BKV infections were differentiated based on the enzymatic digestion of the amplified products using BamHI endonuclease. The results indicated that none of the patients in either group was infected with the BKV, whereas 11.1% (11/99) of the control group subjects and 4% (4/100) of the kidney patients were infected with the JCV. High levels of urea in the excreted urine, low urinary cellularity, reduced bladder washout and a delay in analysing the samples may have contributed to the low prevalence of infection. The results indicate that there is a need to increase the sensitivity of assays used to detect viruses in patients with CDK, especially given that polyomavirus infections, especially BKV, can lead to a loss of kidney function following transplantation.

Atrofia cerebelosa por el virus JC en un paciente con SIDA / Cerebellar atrophy by the JC virus in a patient with AIDS

The progressive multifocal leukoencephalopathy (PML) is a demyelinating CNS disease, characterized by lysis of injected oligodendrocytes by JC virus (JCV). Immunodeficiency is a predisposing factor for acquiring the disease and at least 5 percent of AIDS patients may develop PML. Among patients infected with HIV has also been described the lysis of the granullar cells of the cerebellum and cerebellar atrophy, attributed to a variant of the JCV. We present 37 years old HIV infected men, with postural dizziness, followed by gait disturbances, and a cerebellar syndrome, scanned speech, hyperreflexia, pendular reflexes, Babinski sign and mild cognitive impairment were present. Brain MRI showed hyperintense areas of the white matter in the cerebral hemispheres, thalamus and brainstem, associated with incipient atrophy of the cerebellum. The CSF was normal except for the PCR positive for the JCV. The patient received antiretroviral therapy. A second MRI, eight months later, showed a slightly increase in lesions of the cerebral hemispheres, and the left cerebellar hemisphere, but had developed a marked cerebellar atrophy. After two years, the patient remained with a serious cerebellar syndrome. That in association with the slow course of the disease and the particular cerebellar lesions, are suggestive of a mixed JCV infection of both, the typical and mutant type, in this patient. This is the first case of cerebellar atrophy by the JCV reported in the Chilean literature.

La leucoencefalopatía multifocal progresiva es un proceso desmielinizante del SNC, que se caracteriza por la lisis de los oligodendrocitos infectados por el virus JC. La inmunodeficiencia es un factor predisponente para adquirir la enfermedad y al menos el 5 por ciento de los pacientes con SIDA pueden desarrollar una LMP. Entre pacientes infectados con VIH también se ha descrito una lisis de las células granulosas del cerebelo y atrofia cerebelosa, atribuida a una variante del virus JC. Se presenta un hombre de 37 años portador de VIH, que consulta por vértigos posturales, seguidos de alteraciones de la marcha y un síndrome cerebeloso, palabra escandida, hiperreflexia, reflejos pendulares, Babinski y un leve deterioro cognitivo. La RM cerebral mostró áreas de hiperintensidad en T2 de la substancia blanca en los hemisferios cerebrales, en los tálamos y en estructuras bulbo-protuberanciales, asociadas a una atrofia incipiente del cerebelo. El LCR era normal, salvo la PCR positiva para el VJC. El paciente estaba con terapia antiretroviral que se mantuvo. Una segunda RM, ocho meses después, mostró leve aumento de las lesiones de los hemisferios cerebrales, de la protuberancia y del hemisferio cerebeloso izquierdo, pero se había incrementado la atrofia de la corteza cerebelosa. Después de dos años, el paciente ha mantenido el síndrome cerebeloso, que unido a la detención clínica de la enfermedad y a la atrofia del cerebelo, sugieren que este paciente pudiera tener una doble infección por VJC tanto de la variedad típica como de la mutante. Este sería el primer caso de atrofia cerebelosa por el VJC pesquisado en Chile.

Polyomavirus (BK Virus) Nephropathy in Kidney Transplant Patients: A Pathologic Perspective

Reactivation of polyoma virus (BK virus) is a significant cause of morbidity in kidney transplant patients. This seemingly insignificant viral infection that affects the majority of population at a young age, once reactivated by immunosuppression, is a major factor contributing to graft loss. Screening techniques have been developed for early prediction of BK virus reactivation. These include plasma and urine assays for detection of BK virus DNA by PCR, urine cytology for detection of "decoy cells" and electron microscopy. Combining urine cytology and serology screening can be more effective for early detection of BK virus reactivation. Immunohistochemistry can be utilized as an additional tool to support the diagnosis. Once screening tests reveal a suspicious BK virus reactivation, tissue biopsy should be performed to confirm the diagnosis, rule out acute cellular rejection and plan treatment approaches. Treatment normally includes decreasing immunosuppression and the use of antiviral drug therapy. Unfortunately, disease outcome is often unfavorable and can culminate with eventual graft loss. Renal retransplantation has been performed with mixed results. As new data emerges, we will gain a better understanding of the disease caused by BK virus and respond with improved early diagnosis and treatment to preserve graft function.