Is Your Kid Actin Out? A Series of Six Patients With Inherited Actin-Related Protein 2/3 Complex Subunit 1B Deficiency and Review of the Literature.

BACKGROUND: Hereditary actin-related protein 2/3 complex subunit 1B deficiency is characterized clinically by ear, skin, and lung infections, bleeding, eczema, food allergy, asthma, skin vasculitis, colitis, arthritis, short stature, and lymphadenopathy. OBJECTIVE: We aimed to describe the clinical, laboratory, and genetic features of six patients from four Mexican families. METHODS: We performed exome sequencing in patients of four families with suspected actinopathy, collected their data from medical records, and reviewed the literature for reports of other patients with actin-related protein 2/3 complex subunit 1B deficiency. RESULTS: Six patients from four families were included. All had recurrent infections, mainly bacterial pneumonia, and cellulitis. A total of 67% had eczema whereas 50% had food allergies, failure to thrive, hepatomegaly, and bleeding. Eosinophilia was found in all; 84% had thrombocytopenia, 67% had abnormal-size platelets and anemia. Serum levels of IgG, IgA, and IgE were highly increased in most; IgM was normal or low. T cells were decreased in 67% of patients, whereas B and NK cells were increased in half of patients. Two of the four probands had compound heterozygous variants. One patient was successfully transplanted. We identified 28 other patients whose most prevalent features were eczema, recurrent infections, failure to thrive, bleeding, diarrhea, allergies, vasculitis, eosinophilia, platelet abnormalities, high IgE/IgA, low T cells, and high B cells. CONCLUSION: Actin-related protein 2/3 complex subunit 1B deficiency has a variable and heterogeneous clinical spectrum, expanded by these cases to include keloid scars and Epstein-Barr virus chronic hepatitis. A novel deletion in exon 8 was shared by three unrelated families and might be the result of a founder effect.

Cytomegalovirus infection and disease in pediatric liver transplantation: Burden of disease under a preemptive therapy approach.

BACKGROUND: CMV remains a frequent complication after liver transplantation. Few studies exist in children reporting the epidemiology and outcomes of CMV after LT with current prevention strategies. Our goal is to report the incidence of CMV infection and disease in pediatric LT recipients under preemptive therapy, identify risk factors, complications, and adverse reactions to treatment. METHODS: All pediatric LT recipients from a single center (1998-2018) were included. Antigenemia pp65 (1998-2003) and QNAT or both were used to inform preemptive therapy. Cutoff value for starting treatment was Agpp65 > 10 + cells/200 000 or QNAT >1500 copies/ml or any value in high-risk recipients (D+/R-). RESULTS: One hundred eighteen LT were analyzed. CMV infection was detected in 67% of patients, only 44 (37%) required treatment, and 5 (4%) developed CMV disease. All patients responded well to treatment, and no graft or patients were lost to CMV effects. There were no differences in mortality, CMV indirect effects, or other complications between those who required treatment and those who did not. Thirty-two percent of the patients who received antivirals developed an adverse hematological reaction. Risk factors associated with CMV infection requiring treatment were D+/R- (OR 13.9, p = .01) and fulminant hepatitis (OR 4.8, p = .02). CONCLUSIONS: Preemptive therapy for CMV in children is safe and effective, yields low CMV infection rates that require treatment, and minimal rates of CMV disease, without increasing CMV-related complications. Using this strategy, 63% of our patients did not receive treatment. Therefore, drug exposure, adverse reactions, and resistance risk were minimized.

Mutational spectrum of Mexican patients with tyrosinemia type 1: In silico modeling and predicted pathogenic effect of a novel missense FAH variant.

BACKGROUND: Tyrosinemia type 1 (HT1, MIM#276700) is caused by a deficiency in fumarylacetoacetate hydrolase (FAH) and it is associated with severe liver and renal disfunction. At present, the mutational FAH (15q25.1, MIM*613871) spectrum underlying HT1 in the Mexican population is unknown. The objective of this study was to determine the FAH genotypes in eight nonrelated Mexican patients with HT1, who were diagnosed clinically. METHODS: Sequencing of FAH and their exon-intron boundaries and in silico protein modeling based on the crystallographic structure of mouse FAH. RESULTS: We identified pathogenic variants in 15/16 studied alleles (93.8%). Nine different variants were found. The most commonly detected HT1-causing allele was NM_000137.2(FAH):c.3G > A or p.(?) [rs766882348] (25%, n = 4/16). We also identified a novel missense variant NM_000137.2(FAH):c.36C > A or p.(Phe12Leu) in a homozygous patient with an early and fatal acute form. The latter was classified as a likely pathogenic variant and in silico protein modeling showed that Phe-12 residue substitution for Leu, produces a repulsion in all possible Leu rotamers, which in turn would lead to a destabilization of the protein structure and possible loss-of-function. CONCLUSION: HT1 patients had a heterogeneous mutational and clinical spectrum and no genotype-phenotype correlation could be established.

Simultaneous Detection of Beta and Gamma Human Herpesviruses by Multiplex qPCR Reveals Simple Infection and Coinfection Episodes Increasing Risk for Graft Rejection in Solid Organ Transplantation.

Herpesviruses are common components of the human microbiome that become clinically relevant when a competent immunosurveillance is compromised, such as in transplantation. Members of the beta and gamma subfamilies are associated with a wide diversity of pathologies, including end-organ disease and cancer. In this study, we developed a multiplex qPCR technique with high specificity, sensitivity, efficiency and predictability that allowed the simultaneous detection and quantification of beta and gamma human herpesviruses. The technique was tested in a cohort of 34 kidney- or liver-transplanted pediatric patients followed up for up to 12 months post-transplant. Viral load was determined in 495 leukocyte-plasma paired samples collected bi-weekly or monthly. Human herpesvirus (HHV) 7 was the herpesvirus most frequently found in positive samples (39%), followed by Epstein-Barr virus (EBV) (20%). Also, EBV and HHV7 were present in the majority of coinfection episodes (62%). The share of positive samples exclusively detected either in leukocytes or plasma was 85%, suggesting that these herpesviruses tended to take a latent or lytic path in an exclusive manner. Infection by human cytomegalovirus (HCMV) and HHV6, as well as coinfection by EBV/HHV7 and EBV/HHV6/HHV7, were associated with graft rejection (RR = 40.33 (p = 0.0013), 5.60 (p = 0.03), 5.60 (p = 0.03) and 17.64 (p = 0.0003), respectively). The routine monitoring of beta and gamma herpesviruses should be mandatory in transplant centers to implement preventive strategies.

Pediatric transplantation case conference: Update on cytomegalovirus.

The prevention and management of cytomegalovirus (CMV) remain challenging in children who have undergone solid organ transplantation, despite the availability of effective antiviral medications and sensitive diagnostic assays. The primary objective of this invited commentary is to provide an updated and multidisciplinary approach to persistently challenging CMV cases that commonly occur in pediatric transplantation candidates and recipients, including cases for which published data are frequently lacking.

A Novel c.91dupG JAG1 Gene Mutation Is Associated with Early Onset and Severe Alagille Syndrome.

Alagille syndrome (MIM 118450) is an autosomal dominant disorder characterized by paucity of intrahepatic bile ducts, chronic cholestasis, pulmonary stenosis, butterfly-like vertebrae, posterior embryotoxon, and dysmorphic facial features. Most cases are caused by JAG1 gene mutations. We report the case of a 2-year-old Mexican mestizo patient with Alagille syndrome, having exhibited jaundice and cholestatic syndrome as of three weeks of age. Sequencing analysis of the JAG1 gene revealed the novel heterozygous mutation c.91dupG that originates a truncated protein and therefore a possibly diminished activation of the Notch signaling pathway. The latter may explain the severe phenotype of the patient. Since the mutation was not identified in the parents, it was considered a de novo event, highlighting the importance of molecular diagnosis and genetic counseling. In conclusion, this report widens the spectrum of JAG1 gene mutations associated with Alagille syndrome.

Consensus, Dilemmas, and Challenges in Living Donor Liver Transplantation in Latin America.

We reviewed the history, volume, outcomes, uniqueness, and challenges of living donor liver transplantation (LDLT) in Latin America. We used the data from the Latin American and Caribbean Transplant Society, local transplant societies, and opinions from local transplant experts. There are more than 160 active liver transplant teams in Latin America, but only 30 centers have used LDLT in the past 2 years. In 2014, 226 LDLTs were done in the region (8.5% of liver transplant activities). Living donor liver transplantation is mainly restricted to pediatric patients. Adult-to-adult LDLT activities decreased after the implementation of the model for end-stage liver disease score and a concomitant increase on the rate of deceased donors per million population. Posttransplant outcome analysis is not mandatory, transparent or regulated in most countries. More experienced teams have outcomes comparable to international expert centers, but donor and recipient morbidity might be underreported. Latin America lags behind in terms of the number of adult LDLT and the rate of living donor utilization in comparison with other continents with similar donation rates. Local alliances and collaborations with major transplant centers in the developed world will contribute to the development of LDLT in Latin America.

Pediatric liver transplantation in Latin America: Where do we stand?

LT started in LA in 1968, and pediatric LT records are available starting in the 1990s. Currently, eight countries perform pediatric LT in LA. Registries by national organizations fail to report robust data on pediatric LT. The aim of this paper was to report on the pediatric LT activity in LA. Data were gathered retrospectively through information available in the national registries websites and from local centers. Of the eight countries that report pediatric LT activity, Brazil, Argentina, Mexico, and Colombia have adequate registries of the numbers of LT performed. These countries concentrate most of the activity for pediatric LT. A total of 4593 pediatric LT were reported in LA. Websites for national organizations do not provide open data on post-transplant survival rates or waiting list mortality. The information herein is based on reports by local centers. Overall, survival from select centers is similar to that reported on North American and European registries, between 80 and 90% in the first year post-transplant. In conclusion, pediatric LT activity is growing in LA, especially in Brazil and Argentina. However, the lack of an appropriate LA registry restricts the assessment of quality and therefore restricts interventions aimed at quality improvements in different regions.

Correlation between viral load of cytomegalovirus and tacrolimus and sirolimus levels in transplanted pediatric patients / Correlación entre la carga viral de citomegalovirus y los niveles de tacrolimus y sirolimus en pacientes pediátricos trasplantados

Abstract: Introduction: Survival of transplant patients and grafts depends largely on the use of immunosuppressive drugs. However, a balance remains to be established among immunosuppression, transplant rejection and cytomegalovirus (CMV) infection, which results in a high rate of morbidity and mortality. The aim of this study was to define a better strategy for monitoring transplanted patients based on the analysis of the blood concentration of sirolimus and tacrolimus and the burden of CMV. Methods: Fifty five post-transplant (kidney and liver) pediatric patients, nine treated with sirolimus and 46 treated with tacrolimus, were included. A total of 541 measurements were obtained. In each measurement the concentration of immunosuppressant in whole blood and CMV viral load in plasma and whole blood was quantified by real-time PCR. Pearson correlation coefficient (r) was estimated. Results: Values of r ≤ 0.0747 were found for the relationship between dose and concentration of immunosuppressant; r = 0.9406 for the relationship between viral load in whole blood and plasma, and r ≤ 0.4616 for the relationship between concentration of immunosuppressant and viral load. Conclusions: These data support that the doses of immunosuppressive drugs do not correlate with the levels of the same in whole blood. Therefore, systemic levels of immunosuppressant should be constantly monitored together with CMV load. Meanwhile, a high correlation between viral load measured in whole blood and plasma was found.

Resumen: Introducción: La supervivencia de pacientes trasplantados y de los injertos depende en gran medida del uso de fármacos inmunosupresores. Sin embargo, aún no se ha logrado establecer un balance entre la inmunosupresión, el rechazo al trasplante y la infección por citomegalovirus (CMV), lo cual deriva en una alta tasa de morbilidad y mortalidad. El objetivo de este trabajo fue definir una mejor estrategia de seguimiento de los pacientes trasplantados a partir del análisis de la concentración en sangre de sirolimus y tacrolimus y la carga de CMV. Métodos: Se incluyeron 55 pacientes pediátricos post-trasplante (riñón e hígado), nueve en tratamiento con sirolimus y 46 en tratamiento con tacrolimus. Se obtuvieron 541 mediciones en total. En cada medición se cuantificó la concentración de inmunosupresor en sangre total y la carga viral de CMV en plasma y sangre total mediante PCR en tiempo real. Se calculó el coeficiente de correlación de Pearson (r). Resultados: Se encontraron valores de r ≤ 0.0747 para la relación entre dosis y concentración del inmunosupresor; de r = 0.9406 para la relación de la carga viral entre suero y sangre total y de r ≤ 0.4616 para la relación entre concentración de inmunosupresor y carga viral. Conclusiones: Estos datos apoyan que la dosis de los fármacos inmunosupresores no correlaciona con los niveles de los mismos en sangre total. Por ello, deben ser constantemente monitoreados junto con la carga viral. Por su parte, se encontró alta correlación entre la carga viral medida en sangre total y plasma.

Correlation between viral load of cytomegalovirus and tacrolimus and sirolimus levels in transplanted pediatric patients.

INTRODUCTION: Survival of transplant patients and grafts depends largely on the use of immunosuppressive drugs. However, a balance remains to be established among immunosuppression, transplant rejection and cytomegalovirus (CMV) infection, which results in a high rate of morbidity and mortality. The aim of this study was to define a better strategy for monitoring transplanted patients based on the analysis of the blood concentration of sirolimus and tacrolimus and the burden of CMV. METHODS: Fifty five post-transplant (kidney and liver) pediatric patients, nine treated with sirolimus and 46 treated with tacrolimus, were included. A total of 541 measurements were obtained. In each measurement the concentration of immunosuppressant in whole blood and CMV viral load in plasma and whole blood was quantified by real-time PCR. Pearson correlation coefficient (r) was estimated. RESULTS: Values of r ≤0.0747 were found for the relationship between dose and concentration of immunosuppressant; r = 0.9406 for the relationship between viral load in whole blood and plasma, and r ≤0.4616 for the relationship between concentration of immunosuppressant and viral load. CONCLUSIONS: These data support that the doses of immunosuppressive drugs do not correlate with the levels of the same in whole blood. Therefore, systemic levels of immunosuppressant should be constantly monitored together with CMV load. Meanwhile, a high correlation between viral load measured in whole blood and plasma was found.

Polymorphism analysis and new JAG1 gene mutations of Alagille syndrome in Mexican population.

Alagille syndrome is a multisystem disorder with an autosomic dominant pattern of inheritance that affects the liver, heart, eyes, kidneys, skeletal system and presents characteristic facial features. Mutations of the JAG1 gene have been identified in 20-89% of the patients with Alagille syndrome, this gene encodes for a ligand that activates the Notch signaling pathway. In the present study we analyzed 9 Mexican patients with Alagille syndrome who presented the clinical criteria for the classical presentation of the disease. By using the denaturing high performance liquid chromatography mutation analysis we were able to identify different mutations in 7 of the patients (77.77%), importantly, we found 5 novel mutations in JAG1 gene. The allelic frequency distribution of 13 polymorphisms in Mexican population is also reported. The overall results demonstrated an expanding mutational spectrum of JAG1 gene in the Mexican population.

Guidelines for the diagnosis and treatment of extrahepatic portal vein obstruction (EHPVO) in children.

INTRODUCTION: Extrahepatic portal vein obstruction is an important cause of portal hypertension among children. The etiology is heterogeneous and there are few evidences related to the optimal treatment. AIM AND METHODS: To establish guidelines for the diagnosis and treatment of EHPVO in children, a group of gastroenterologists and pediatric surgery experts reviewed and analyzed data reported in the literature and issued evidence-based recommendations. RESULTS: Pediatric EHPVO is idiopathic in most of the cases. Digestive hemorrhage and/or hypersplenism are the main symptoms. Doppler ultrasound is a non-invasive technique with a high degree of accuracy for the diagnosis. Morbidity is related to variceal bleeding, recurrent thrombosis, portal biliopathy and hypersplenism. Endoscopic therapy is effective in controlling acute variceal hemorrhage and it seems that vasoactive drug therapy can be helpful. For primary prophylaxis of variceal bleeding, there are insufficient data for the use of beta blockers or endoscopic therapy. For secondary prophylaxis, sclerotherapy or variceal band ligation is effective; there is scare evidence to recommend beta-blockers. Surgery shunt is indicated in children with variceal bleeding who fail endoscopic therapy and for symptomatic hypersplenism; spleno-renal or meso-ilio-cava shunting is the alternative when Mesorex bypass is not feasible due to anatomic problems or in centers with no experience. CONCLUSIONS: Prospective control studies are required for a better knowledge of the natural history of EHPVO, etiology identification including prothrombotic states, efficacy of beta-blockers and comparison with endoscopic therapy on primary and secondary prophylaxis.

Liver exhibits thermal variations according to the stage of fibrosis progression: A novel use of modulated-differential scanning calorimetry for research in hepatology.

AIM: Liver fibrosis results in a disproportion of the hepatic composition and architecture, characterized by a progressive accumulation of fibrillar proteins at the liver parenchyma. Modulated-differential scanning calorimetry (mDSC) is an experimental methodology able to determine the specific thermal signature from any biological substance, based on the variation in heat flow and heat capacity. As these physicochemical properties are directly influenced by compositional and structural changes, we decided to study the thermal behavior of the liver during fibrosis using mDSC. METHODS: Liver fibrosis was induced in rats by bile duct ligation or carbon tetrachloride administration. Degree of liver fibrosis was determined by histological examination using the Masson-trichrome stain, accompanied by hepatic expression of α-smooth muscle actin. The thermal analysis was performed in a modulated-differential scanning calorimeter using 20 mg of fresh liver mass. RESULTS: The liver showed a characteristic thermal signature in control animals, which progressively differed among mild (F1), moderate (F2) and advanced (F3-F4) liver fibrosis. For heat flow, the hepatic thermal signature from F3-F4 rats exhibited significant differences when compared with F1, F2 and controls. In terms of heat capacity, liver specimens provided a specific thermal signature for each stage of disease, characterized by a transition temperature onset at 95°C for controls, whereas in F1, F2 and F3-F4 animals this temperature significantly decreased to 93°C, 84°C and 75°C, respectively. CONCLUSION: Because the liver shows a differential thermal signature according to the degree of fibrosis, mDSC could be a novel tool in the study of liver fibrosis progression.

[Pediatric liver transplant program at Hospital Infantil de Mexico Federico Gomez]. / Programa de trasplante hepático pediátrico en el Hospital Infantil de México Federico Gómez.

This article reports the experience of the largest pediatric liver transplant (LT) program in México. Between June 1998 and May 2011, 76 LT were performed in 74 recipients, including 80% cadaveric-whole organ grafts and 20% segmental grafts, 12% of those coming from live donors and 8% from cadaver reduced donors. The most common indication for LT was biliary atresia (43%), followed by metabolic disorders (13%) and fulminant hepatitis (12%). Most of the recipients were infants or toddlers weighing <15 kg (age range 0.7-17.2 years, weight range 6.5-66 kg), 73% had moderate to severe malnutrition and 72% had multiples surgeries previous to LT. There were 9 cases of hepatic artery thrombosis (11.8%) and 2 portal vein thrombosis (2.6%), however, 8 of these 10 grafts were rescued with early thrombectomy and reanastomosis. All biliary complications (19 cases, 25%) were solved with medical or surgical interventions and did not cause any graft loss. Acute cellular rejection (30 cases, 39%) required thymoglobulin in only 3 cases and chronic rejection (4 cases, 5%) has been retransplanted in 2 cases. CMV infection or reactivation occurred in 30% of cases and easily responded to preemptive therapy. Nine recipients developed postLT neoplasias (7 post-transplant lymphoproliferative disorders, one multivisceral Kaposi sarcoma and one systemic smooth muscle tumor). Five of them responded to decreasing or discontinuing immunosuppression, and 2 are completely tolerant to the graft. The one and five-year patient survival for those LT performed during 2001-2011 was 85 and 75%. The first successful live donor LT in the country was performed in 2001 at this program, as was the first simultaneous liver-kidney transplant in a child. This is the largest and most successful pediatric LT series in the country. Our results demonstrate that pediatric LT is a feasible undertaking in Mexico, with survival rates similar to those of foreign centers.

Cellular senescence in livers from children with end stage liver disease.

BACKGROUND: Senescent cells occur in adults with cirrhotic livers independent of the etiology. AIM: Investigate the presence rate of cellular senescence and expression of cell cycle check points in livers from children with end stage disease. METHODOLOGY/PRINCIPAL FINDINGS: Livers of five children aged three years or less undergoing liver transplantation due to tyrosinemia (n = 1), biliary atresia (n = 2), or fulminant hepatitis (n = 2) were analyzed for senescence associated beta-galactosidase (SA-betagal) activity and p16INK4a, p21cip1 and p53. All livers displayed positive cellular staining for SA-betagal in the canals of Hering and interlobular biliary ducts. In the presence of cirrhosis (3/5 cases) SA-betagal was found at the cholangioles and hepatocytes surrounding the regenerative nodules. Children with fulminant hepatic failure without cirrhosis had significant ductular transformation with intense SA-betagal activity. No SA-betagal activity was evident in the fibrous septa. Staining for p53 had a similar distribution to that observed for SA-betagal. Staining for p16(INK4a) and p21(cip1) was positive in the explanted liver of the patient with tyrosinemia, in the hepatocytes, the canals of Hering, cholangioles and interlobular bile ducts. In the livers with fulminant hepatitis, p21(cip1) staining occurred in the areas of ductular transformation and in the interlobular bile ducts. CONCLUSIONS/SIGNIFICANCE: Cellular senescence in livers of children with end stage disease is associated with damage rather than corresponding to an age dependent phenomenon. Further studies are needed to support the hypothesis that these senescence markers correlate with disease progression.

Alteraciones de la vena porta en pacientes con atresia de vías biliares extrahepáticas / Portal vein alterations in patients with extrahepatic biliary atresia

Introducción. Las lesiones vasculares del hígado son diversas y pueden observarse en varias condiciones. En la atresia de vías biliares extrahepáticas (AVBE) se han descrito lesiones arteriales; sin embargo, hasta donde sabemos, alteraciones en las venas portales no han sido descritas con anterioridad. El propósito de este trabajo es el de informar de algunas lesiones peculiares de la vena porta observadas en un grupo de pacientes con AVBE. Métodos. Estudio retrospectivo, descriptivo de 62 biopsias consecutivas de pacientes con AVBE a los que se les practicó cirugía derivativa. Se estudiaron los vasos del hilio hepático con tinciones de hematoxilina eosina, Masson, fibras elásticas, mucicarmín, azul alciano, PAS, hierro coloidal, CD20, CD3, CD68, y actina. Se evaluó: proliferación fibrosa o celular subendotelial, daño a la elástica, edema, calcificación, trombosis y depósito de glicosaminoglicanes. La extensión del daño se graduó como leve (menos de 25% de la circunferencia), moderado (26 a 50%), o extenso (más de 50%). De acuerdo a su diámetro, los vasos fueron clasificados como de tamaño medio o grande; se evaluaron la vena portal o sus ramas mayores. Los explantes hepáticos (n =20) de pacientes sin AVBE se utilizaron como testigos, y los datos clínicos y demográficos se obtuvieron de los expedientes. Resultados. La edad promedio fue de 3 meses; 45 fueron niñas. En 24 casos se obtuvo vena porta o sus ramas principales. Se encontraron alteraciones vasculares en 35 casos: arteriales en 13, venosas en 10, y daño en ambas en 12. Los cambios arteriales principales fueron: ruptura de la capa elástica (n =19) y proliferación celular subendotelial (n =20); todos los cambios fueron de leves a moderados. Los cambios venosos principales fueron: depósito de glicosaminoglicanes (n =7), proliferación fibrosa subendotelial (n =8) y ruptura de las fibras elásticas (n =9); todos fueron cambios leves. La proliferación subendotelial estuvo compuesta por macrófagos, linfocitos CD20 y CD3 y miofibroblastos. Las alteraciones se observaron desde edades tempranas y no estuvieron presentes en los testigos. Conclusión. Las alteraciones vasculares fueron comúnmente observadas en la AVBE, los cambios en la vena porta que se observaron en un tercio de nuestros casos, parecen ser parte del proceso y no una condición adquirida; podrían explicar algunas complicaciones quirúrgicas del trasplante hepático y apoyar las teorías vascular y autoinmune sobre el origen de la AVBE.

Introduction. Vascular lesions of the liver are varied and may be observed in different conditions; arterial lesions have been observed in extrahepatic biliary atresia (EBA). To our knowledge, alterations of the portal vein or its main branches have not been described previously. The aim of this article is to inform peculiar portal vein lesions found in a group of patients with EBA. Methods. This is a descriptive, retrospective study of 62 consecutive biopsies of patients with EBA who underwent portoenteral anastomosis over a 10 year period. Vessels from the hepatic hilium were studied with hematoxylin & eosin, Masson's trichrome, elastic fibers, mucicarmine, alcian blue, PAS, coloidal iron, CD20, CD3, CD68, and actin stains. Cellular or fibrous subendothelial proliferation, tunica elastica damage, edema, calcification, thrombosis, and glycosaminoglycan deposits were searched; the extension of damage was graded as mild (less than 25% of circumference), moderate (26 to 50%), or severe (over 50%). Vessels were classified according to their circumference as medium sized (less than 300 microns) and large; when possible the portal vein and/or its larger branches were evaluated. Hepatic explants (n =20) of patients without EBA were used as controls. Demographic data were obtained from clinical charts. Results. Age averaged 3 months; 45 patients were female. In 24 cases, portal vein or its larger branches were present. Vascular alterations were observed in 35 cases: arterial changes in 13, vein lesions in 10, and both types of damage in 12. The main arterial changes found were: elastic rupture (n =19), glycosaminoglycans deposits (n =19), and subendothelial cellular proliferation (n =20); all changes were mild to moderate. On the other hand, glycosaminoglycans deposits (n =7), sub-endothelial fibrous proliferation (n =8), and elastic fibers rupture (n =9) were the main alterations observed in the portal vein or its branches; these changes were mild. Subendothelial cellular proliferation was composed of macrophages, B and T lymphocytes, and myofibroblasts. These alterations were present since early ages and not observed in control subjects. Conclusions. Vascular alterations were commonly observed in EBA. Portal vein changes were present at least in one third of cases studied, and they appear to be part of the process and not an acquired condition. These changes may explain some vascular complications of liver transplantation of patients with EBA as well as support vascular and/or autoimmune theories on EBA origin; likewise, they may provide data for future insights on EBA pathogenesis.

Aplasia adquirida de la serie roja por infección por parvovirus B19 en una adolescente con trasplante renal / Pure red cell aplasia caused by parvovirus B19 infection in a female adolescent after renal transplantation

Introducción. El parvovirus B19 ha sido identificado como el agente etiológico del eritema infeccioso o quinta enfermedad, de las crisis aplásicas transitorias en niños con enfermedades hemolíticas, y de la aplasia adquirida de la serie roja en pacientes inmunocomprometidos, incluyendo los pacientes que reciben un trasplante de un órgano sólido o de médula ósea. Caso clínico. Adolescente femenina de 15 años de edad con insuficiencia renal crónica terminal de causa desconocida, quien recibió trasplante renal de donador cadavérico. Dos meses después del trasplante presentó anemia grave arregenerativa que requirió transfusiones de sangre, sin responder a la suspensión del tratamiento con mofetil micofenolato. Aunque la investigación de anticuerpos IgM e IgG contra el parvovirus B19 fue negativa, se encontró positividad en la investigación del DNA viral por medio de la prueba de reacción en cadena de la polimerasa. El estudio de la médula ósea mostró el patrón característico de pronormoblastos con cambios megaloblásticos y vacuolas en el citoplasma y detención en la maduración a nivel de los normoblastos. El tratamiento con inmunoglobulina intravenosa por 10 días se acompañó de respuesta reticulocitaria adecuada y corrección de la anemia. Conclusiones. En los pacientes con trasplante renal y anemia grave arregenerativa debe investigarse la presencia de parvovirus B19, preferentemente a través de la prueba de reacción en cadena de la polimerasa. El tratamiento con inmunoglobulina intravenosa es el más adecuado para eliminar la infección y corregir el cuadro anémico.

Introduction. Parvovirus B19 can present in children as erythema infectious rash, aplastic anemia in patients with hemolytic diseases and pure red cell aplasia in immunocompromised patients, such as in bone marrow and solid organ transplant recipients. Case report. A 15-year-old female with end stage renal disease of unknown origin received a renal transplant from a cadaveric donor. Two months after the transplant, she presented severe arregenerative anemia despite mofetil micofenolate withdrawal and required blood transfusions. IgM and IgG titers for parvovirus B19 were negative, but DNA polymerase chain reaction was positive. Bone marrow showed the characteristic pattern of pronormoblasts with megaloblastic changes and cytoplasmic vaculations, with maturation arrest at normoblast level. The patient was treated with intravenous immunoglobulin for 10 days with adequate reticulocyte response and resolution of her anemia. Conclusions. Parvovirus B19 should be investigated in renal transplant patients with severe arregenerative anemia; DNA polymerase reaction test is the diagnostic test of choice. Treatment with intravenous immunoglobulin is the recommended therapy for the control and elimination of the infection and anemia resolution.

Trasplante renal en pediatría / Renal transplantation in children

Despite being considered a high risk procedure, renal transplantation has been recognized for more than 20 years as the best therapeutic option for children with end-stage renal disease since it is superior than any available dialytic procedure in improving the neuropsychological development and the quality of life. Today pediatric patients have similar graft survival than adults, and 10 year-old children or less have better outcome than any other age group. These remarking results are due to the development of specialized pediatric transplant centers and research programs, improvement in the selection and preparation of donors and recipients, refinement of the surgical technique and the use of new immunossupressive drugs.

El trasplante pediátrico fue considerado durante mucho tiempo de alto riesgo, ya que la sobrevida del injerto no era tan buena como la reportada en pacientes adultos, aún así desde hace 20 años es el tratamiento óptimo para los niños urémicos porque mejora el desarrollo neurológico, psicológico y la calidad de vida en forma muy superior a los procedimientos dialíticos disponibles. Actualmente, gracias al desarrollo de centros de trasplante e investigación especializados en la atención pediátrica, a la mejoría en la preparación y selección de donadores y receptores, en la técnica quirúrgica y a nuevos esquemas inmunosupresores los pacientes pediátricos tienen una sobrevida del injerto similar a la reportada en adultos, de hecho los niños menores de 10 años han logrado tener la mejor sobrevida del trasplante renal de todos los grupos etáreos.

Trasplante hepático en niños / Pediatric liver transplantation

Pediatric liver transplantation has evolved over the last two decades into an effective and widely accepted therapy for infants and children. Currently, these high-risk patients achieve 85 to 90% one-year patient survival and an excellent quality of life. This paper reviews the special features of the pediatric recipient, the surgical innovations developed to be able to offer them a transplant (reduced size, live donor, split, and auxiliary partial transplantation), the most significant issues in anesthetic, immunosuppressive and postoperative care in children, as well as a global picture of the results. Additionally, the experience of the Hospital Infantil de México Federico Gómez is presented, as the largest and most successful series of pediatric liver transplantation in the country, where the first successful live donor liver transplantation and the first simultaneous liver-kidney transplantation in a child were performed.

El trasplante hepático pediátrico ha evolucionado durante las últimas dos décadas, hasta convertirse en una terapia efectiva y ampliamente aceptada para tratar lactantes y niños. Estos pacientes, considerados de alto riesgo, actualmente logran tasas de sobrevida actuarial al año cercanas a 85-90%, con una excelente calidad de vida después del trasplante. Este artículo revisa las particularidades del receptor pediátrico, las innovaciones quirúrgicas que se desarrollaron para poderles ofrecer un trasplante (trasplante reducido, de donador vivo, dividido o "split" y auxiliar parcial), los puntos más importantes del manejo anestésico, inmunosupresión y cuidados postrasplante en niños, y un panorama de los resultados actuales a nivel mundial. Se presenta además la experiencia del Hospital Infantil de México Federico Gómez, que cuenta con la serie de trasplante hepático en niños más grande y con mejores resultados del país, el primer trasplante de hígado de donador vivo con éxito y el primer trasplante hepático-renal simultáneo en un niño en México.

[Renal transplantation in children]. / Trasplante renal en pediatría.

Despite being considered a high risk procedure, renal transplantation has been recognized for more than 20 years as the best therapeutic option for children with end-stage renal disease since it is superior than any available dialytic procedure in improving the neuropsychological development and the quality of life. Today pediatric patients have similar graft survival than adults, and 10 year-old children or less have better outcome than any other age group. These remarking results are due to the development of specialized pediatric transplant centers and research programs, improvement in the selection and preparation of donors and recipients, refinement of the surgical technique and the use of new immunossupressive drugs.