Full Validation and Application to Clinical Research of a High-Performance Liquid Chromatography Method for the Assessment of Urinary 3-Indoxyl Sulfate in Pediatric Patients with Hematopoietic Stem Cell Transplant.

3-indoxyl sulfate (3-IS) results from a hepatic transformation of indole, a tryptophan degradation product produced by commensal gut bacteria. The metabolite has shown promise as a biomarker of dysbiosis and clinical outcomes following hematopoietic stem cell transplant (HSCT) in adults. Nonetheless, there is a paucity of data regarding microbiome health and outcomes in the pediatric HSCT setting. We developed and thoroughly validated an affordable high-performance liquid chromatography/fluorescence detector (HPLC-FLD) method to quantify 3-IS in urine for use in the pediatric setting. Chromatographic separation was achieved on a C18 column (250 × 4.6 mm × 5 µm) with a mobile phase consisting of pH 4.0 acetic acid-triethylamine buffer and acetonitrile (88:12, v/v), eluted isocratically at 1 mL/min. 3-IS fluorescence detection was set at excitation/emission of 280 and 375, respectively. The method was fully validated according to FDA-specified limits including selectivity, linearity (0.10 to 10.00 mg/L, r2 > 0.997), intra- and inter-day accuracy, and precision. 3-IS stability was confirmed after three freeze-thaw cycles, for short- and medium-term on a benchtop and at 4 °C and for long-term up to 60 days at -20 °C. The validated method was used to quantify 3-IS in urine samples from HSCT pediatric patients.

Comparison of SARS-CoV-2 viral load in asymptomatic and symptomatic children attended in a referral public pediatric hospital in Argentina / Comparación de la carga viral de SARS-CoV-2 en niños asintomáticos y sintomáticos atendidos en un hospital pediátrico público de referencia en Argentina

Abstract At present, different reports have shown that children reach similar SARS-CoV-2 viral load (VL) levels compared to adults; however, the impact of VL on children remains ambiguous when asymptomatic versus symptomatic cases are compared. Thus, the aim of this study was to assess VL at the time of diagnosis in asymptomatic and symptomatic SARS-CoV-2 infected children. VL analysis was retrospectively carried out from nasopharyngeal swabs on 82 SARS-CoV-2 infected children, from March to October 2020. Of the 82 children, 31 were asymptomatic. Symptomatic patients had significantly higher VL values compared to asymptomatic ones (median = 7.41 vs4.35 log10 copies/ml, respectively). Notwithstanding, 8 out of 31 asymptomatic children had high VL levels, overlapping levels observed above the first quartile in the symptomatic group. Analysis of different age groups revealed that median VL values were higher in the symptomatic groups, although there was only a significant difference in children younger than 5 years of age. On the other hand, there was no significant difference between the VL values from the 82 SARS-CoV-2 infected children according to age, sex, underlying disease, symptoms or severity of COVID-19 related disease. This study emphasizes the importance of VL analysis in SARS-CoV-2 infected children, who could contribute to viral spread in the community. This concern could be extended to healthcare workers, who are in contact with children.

Resumen Diferentes informes han demostrado que los ninos alcanzan niveles de carga viral (CV) de SARS-CoV-2 similares a los de los adultos, pero el impacto de la CV en los niños continua siendo incierto cuando se compara entre aquellos que son asintomáticos y sintomáticos. El objetivo de este estudio fue evaluar la CV al momento del diagnóstico en ninos asintomáticos y sintomáticos infectados por SARS-CoV-2. El análisis de CV se realizó retrospectivamente a partir de muestras de hisopados nasofaríngeos de 82 niños infectados por SARS-CoV-2 entre marzo y octubre de 2020. De ellos, 31 eran asintomáticos. Encontramos que el grupo sintomático tenía valores de CV significativamente más altos en comparación con el grupo asintomático (mediana = 7,41 vs. 4,35 log10 copias/ml, respectivamente). No obstante, 8 de los 31 ninos asintomáticos presentaron valores de CV elevados, equivalentes a los observados por encima del primer cuartil del grupo sintomático. El análisis por grupos de edad reveló que la mediana de CV fue más alta en los niños sintomáticos, aunque esta diferencia fue significativa solamente en los menores de 5 anos. A su vez, los valores de CV obtenidos a partir de los 82 niños infectados por SARS-CoV-2 no mostraron diferencias significativas según el grupo etario, el sexo, la enfermedad de base, los síntomas y la gravedad de la COVID-19. Este estudio enfatiza la necesidad del análisis de la CV en ninos infectados por SARS-CoV-2, quienes podrían contribuir a la propagación del virus en la comunidad. Esta preocupación podría extenderse a los trabajadores de la salud que están en contacto con los ninños.

Comparison of SARS-CoV-2 viral load in asymptomatic and symptomatic children attended in a referral public pediatric hospital in Argentina.

At present, different reports have shown that children reach similar SARS-CoV-2 viral load (VL) levels compared to adults; however, the impact of VL on children remains ambiguous when asymptomatic versus symptomatic cases are compared. Thus, the aim of this study was to assess VL at the time of diagnosis in asymptomatic and symptomatic SARS-CoV-2 infected children. VL analysis was retrospectively carried out from nasopharyngeal swabs on 82 SARS-CoV-2 infected children, from March to October 2020. Of the 82 children, 31 were asymptomatic. Symptomatic patients had significantly higher VL values compared to asymptomatic ones (median=7.41 vs 4.35log10 copies/ml, respectively). Notwithstanding, 8 out of 31 asymptomatic children had high VL levels, overlapping levels observed above the first quartile in the symptomatic group. Analysis of different age groups revealed that median VL values were higher in the symptomatic groups, although there was only a significant difference in children younger than 5 years of age. On the other hand, there was no significant difference between the VL values from the 82 SARS-CoV-2 infected children according to age, sex, underlying disease, symptoms or severity of COVID-19 related disease. This study emphasizes the importance of VL analysis in SARS-CoV-2 infected children, who could contribute to viral spread in the community. This concern could be extended to healthcare workers, who are in contact with children.

Analysis of COL7A1 pathogenic variants in a large cohort of dystrophic epidermolysis bullosa patients from Argentina reveals a new genotype-phenotype correlation.

Dystrophic epidermolysis bullosa (DEB) is a clinically heterogeneous heritable skin disorder, characterized by blistering of the skin and mucous membranes following minor trauma. Dominant (DDEB) and recessive (RDEB) forms are caused by pathogenic variants in COL7A1 gene. Argentina's population has a heterogeneous genetic background, and little is known about the molecular basis of DEB in our country or in native South American populations. In this study, we present the prevalence and geographical distribution of pathogenic variants found in 181 patients from 136 unrelated families (31 DDEB and 105 RDEB). We detected 95 different variants, 59 of them were previously reported in the literature and 36 were novel, nine of which were detected in more than one family. The most prevalent pathogenic variants were identified in exon 73 in DDEB patients and in exon 3 in RDEB patients. We also report a new phenotype-genotype correlation found in 10 unrelated families presenting mild blistering and severe mucosal involvement. Molecular studies in populations with an unexplored genetic background like ours revealed a diversity of pathogenic variants, and we hope that these findings will contribute to the definition of targets for new gene therapies.

Induction Versus Maintenance Immunosuppression After Intestinal Transplant: Determining Which Treatment Most Impacts Long-Term Patient And Graft Survival.

OBJECTIVES: Immunosuppressive strategies for intestinal transplant have changed over time. However, specific intestinal transplant-oriented protocols and reports on long-term maintenance regimens are scarce. Our objective was to evaluate the impact of 2 different initial immunosuppressive protocols based on thymoglobulin (group A) and basiliximab (anti-interleukin 2 antibody) (group B) and of changes to maintenance immunosuppression over long-term follow-up in intestinal transplant recipients. MATERIALS AND METHODS: We performed a retrospective analysis of a prospectively established protocol for intestinal transplant immunosuppression, conducted between May 2006 and December 2020. We analyzed 51 intestinal transplant recipients, with 6 patients excluded because of early death or graft loss. Acute cellular rejection frequency and grade, number of acute cellular rejection episodes, time to the first acute cellular rejection episode, response to treatment, number of patients who progressed to chronic allograft rejection, kidney function, infections, incidence of posttransplant lymphoproliferative disorder and graft-versus-host disease, and patient and graft survival were analyzed. RESULTS: In the study groups, there were 87 acute cellular rejection episodes in 45 patients (33 in group A and 54 in group B). We found degree of acute cellular rejection to be mild in 45 patients, moderate in 18, and severe in 24 (not significant between groups). Our comparison of induction therapy (thymoglobulin [group A] vs interleukin 2 antibody [group B]) did not show any statistical difference during clinical followup. Long-term review showed that all patients were on tacrolimus. Five-year patient and graft survival rates were 62% and 45% for group A and 54% and 46% for group B, respectively (not significant). CONCLUSIONS: Long-term patient and graft outcomes reflected the use of an individualized follow-up with adjustments and changes in immunosuppressive medications according to the patient's clinical course and complications rather than based on the induction immunosuppressive protocol used.

Case Report: Hyperinflammatory Status in an Immunocompromised Child With a Highly Sustained Viral Load of SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is spreading throughout the world. Limited data are available for the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load (VL) in immunocompromised pediatric patients. Here, we report the clinical characteristics and the dynamics of SARS-CoV-2 VL of a pediatric patient with acute myeloid leukemia who developed a hyperinflammatory status mimicked MIS-C. The clinical course was characterized by the late onset of fever, GI symptoms, rash, and respiratory distress, including oxygen requirement with sustained VL of SARS-CoV-2 around 7 log10 RNA copies/mL for 6 weeks. It is important to note that the hyperinflammatory status developed early at the third week of hospitalization-in a context of high VL and immunocompromised status. All these characteristics make this clinical case unique. On the other hand, while many reports have characterized the dynamics of SARS-CoV-2 VL in adults and immunocompetent hosts, it remains unreported in pediatrics-even less in immunosuppressed children.

Identification of novel molecular determinants of co-receptor usage in HIV-1 subtype F V3 envelope sequences.

HIV-1 determinants of coreceptor usage within the gp120 V3 loop have been broadly studied over the past years. This information has led to the development of state-of the-art bioinformatic tools that are useful to predict co-receptor usage based on the V3 loop sequence mainly of subtypes B, C and A. However, these methods show a poor performance for subtype F V3 loops, which are found in an increasing number of HIV-1 strains worldwide. In the present work we investigated determinants of viral tropisms in the understudied subtype F by looking at genotypic and structural information of coreceptor:V3 loop interactions in a novel group of 40 subtype F V3 loops obtained from HIV-1 strains phenotypically characterized either as syncytium inducing or non-syncytium inducing by the MT-2 assay. We provide novel information about estimated interactions energies between a set of V3 loops with known tropism in subtype F, that allowed us to improve predictions of the coreceptor usage for this subtype. Understanding genetic and structural features underlying HIV coreceptor usage across different subtypes is relevant for the rational design of preventive and therapeutic strategies aimed at limiting the HIV-1 epidemic worldwide.

Lupus eritematoso sistémico activo, síndrome deactivación macrofágica y sepsis / Active systemic lupus erythematosus, macrophage activation syndrome and sepsis

El síndrome de activación macrofágica (SAM) es una entidad poco frecuente y grave, caracterizadapor una excesiva activación y proliferación de macrófagos y linfocitos T. Los factoresdesencadenantes son las infecciones, drogas, enfermedades malignas y autoinmunes. Ellupus eritematoso sistémico frecuentemente se asocia al SAM. En la práctica clínica, eldiagnóstico diferencial entre lupus eritematoso sistémico activo, SAM e infección es ungran desafío para el médico internista. Esto se debe a que los signos, síntomas y datos delaboratorio de estas entidades se superponen. El propósito de nuestro trabajo es el reportarlos casos de 2 pacientes con lupus eritematoso sistémico activo, SAM y sepsis...

Macrophage activation syndrome (MAS) is a rare and severe entity characterized by excessive activation and proliferation of macrophages and T-lymphocytes. The usual triggers are infections, drugs, malignancy and autoimmune diseases. Systemic lupus erythematosus is frequently associated with MAS. In clinical practice, differential diagnosis between active systemic lupus erythematosus, MAS and an infection is a great challenge for the internist. This happens because signs, symptoms and laboratory data from these illnesses overlap to a large degree. The purpose of this paper is to present a report on two patients with active systemic lupus erythematosus, MAS, and sepsis...

[Tungiasis: a case report]. / Tungiasis: Presentación de un caso clínico.

Tungiasis, is a cutaneous parasitosis, native of America caused by Tunga penetrans. Infestations usually presents with black papular lesions, either single or multiple, most of them localized on the feet, mainly in the subungual and periungual areas. Diagnosis of tungiasis is based on the characteristic aspect of the lesions in a patient coming from an endemic area. Surgical removal of the flea and application of a topical antibiotic is the standard treatment. We describe a case of a 10-years-old girl, with multiple lesions localized on feet, who was succesfully treated with ivermectin and surgical removal of lesions.

Tungiasis: Presentación de un caso clínico / Tungiasis: a case report

La tungiasis es una parasitosis cutánea originaria de América causada por Tunga penetrans. Se caracteriza por lesiones papulares, negruzcas, únicas o múltiples, que suelen afectar los pies, principalmente en las zonas subungueales y periungueales. El diagnóstico de tungiasis se realiza por las características clínicas de las lesiones en un paciente proveniente de zonas endémicas. El tratamiento de elección es la extracción quirúrgica de la pulga y la aplicación de antibióticos tópicos. Presentamos un caso de tungiasis en una paciente de 10 años de edad con múltiples lesiones en ambos pies, que fue tratada satisfactoriamente con ivermectina y extracción quirúrgica.

Tungiasis, is a cutaneous parasitosis, native of America caused by Tunga penetrans. Infestations usually presents with black papular lesions, either single or multiple, most of them localized on the feet, mainly in the subungual and periungual areas. Diagnosis of tungiasis is based on the characteristic aspect of the lesions in a patient coming from an endemic area. Surgical removal of the fea and application of a topical antibiotic is the standard treatment. We describe a case of a 10-years-old girl, with multiple lesions localized on feet, who was succesfully treated with ivermectin and surgical removal of lesions.