Longitudinal Trends in HIV-1 Subtypes and Drug Resistance in Children from Argentina over a 15-Year Period (2006-2021).

Background: Human immunodeficiency virus (HIV) drug resistance is a major cause of treatment failure in children and adolescents infected with the virus. Objectives: The objectives of the study are to investigate HIV drug resistance (HIVDR) in patients who attended a referral care center in Argentina over a 15-year period and to compare mutational patterns between HIV-1 polsequences characterized as B or BF recombinants. Methods: Individual resistance-associated mutations (RAMs) (to protease and reverse transcriptase inhibitors) were identified according to IAS-USA guidelines in 374 HIV-1-infected children and adolescents. HIV-1 subtype was characterized by phylogenetic and recombination analysis using MEGA5.1 and Simplot. Poisson linear regression was used to model the dynamics of the RAMs over time. Results: The prevalence of RAMs to protease inhibitors (R2 = 0.52, p = 0.0012) and nucleoside reverse transcriptase inhibitors (R2 = 0.30, p = 0.0225) decreased over time. HIVDR to non-nucleoside reverse transcriptase inhibitors remained moderate to high, ranging between 33% and 76%. BF recombinants showed a higher frequency of thymidine analog mutation 1 RAMs profile and I54V mutation. Conclusion: In Argentina, HIVDR observed in children and adolescents has decreased over the past 15 years, regardless of the viral subtype. (REV INVEST CLIN. 2024;76(1):29-36).

Variable antiviral activity of islatravir against M184I/V mutant HIV-1 selected during antiretroviral therapy.

BACKGROUND: Islatravir is a new antiretroviral drug that inhibits the reverse transcriptase (RT) of HIV-1 through multiple mechanisms. It is proposed to be used in combination with doravirine, a new NNRTI. M184V/I mutations have been shown to reduce the in vitro antiviral activity of islatravir, but their effect when pre-selected during ART has not been investigated. METHODS: HIV-1 rt sequences were obtained from four individuals of the Garrahan HIV cohort prior to, or during virological failure to ART. HIV-1 infectious molecular clones were constructed on an NL4-3 backbone, and infectious viruses were produced by transfection of 293T cells. Fold-changes in IC50 were calculated for each mutant versus the NL4-3 WT. HIV-1 phenotypic drug resistance was tested in vitro against NRTIs and NNRTIs. RESULTS: In all the cases, M184I/V, either alone or in the presence of other mutations, was associated with reduced susceptibility to islatravir, abacavir and lamivudine. Viruses carrying M184V/I showed variable levels of resistance to islatravir (4.8 to 33.8-fold). The greatest reduction in susceptibility was observed for viruses carrying the mutations M184V + V106I (33.8-fold resistance) or M184V + I142V (25.2-fold resistance). For NNRTIs, the presence of V106I alone did not affect susceptibility to doravirine or etravirine, but showed a modest reduction in susceptibility to efavirenz (6-fold). Susceptibility to doravirine was slightly reduced only for one of the mutants carrying V106I in combination with Y181C and M184V. CONCLUSIONS: Mutations and polymorphisms selected in vivo together with M184V/I depend on the viral genetic context and on ART history, and could affect the efficacy of islatravir once available for use in the clinic.

COVID-19 in Pediatric Cancer Patients and Hematopoietic Stem Cell Transplant Recipients in a Tertiary Care Hospital in Argentina.

The outcome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in cancer pediatric patients was initially uncertain. The objective of this study was to describe the characteristics and outcome of cancer patients and hematopoietic stem cell transplant recipients from 0 to 19 years with detectable SARS-CoV-2 from April 23, 2020, to April 30, 2022, treated in a tertiary-level hospital in Argentina. A total of 348 cases were registered in 339 patients. The median age was 89.5 (3 to 224) months. The sex was predominantly male: 193 (55.5%). The most common malignant disease was leukemia (42.8%). One hundred four cases (29.9%) had comorbidities. Of the 346 cases with an available blood count, 17.6% had a lymphocyte count <300/mm 3 . Fever was the most common symptom. In most cases (93.1%) presented asymptomatic or mild disease. Twenty-one cases (6%) presented severe or critical status. Eleven of 24 admissions to the intensive care unit were due to COVID-19 (coronavirus disease 2019). Eight patients (2.3%) died. Two deaths were attributable to SARS-CoV-2 (0.6%). Being older, having fever, lymphopenia at diagnosis, and having received hematopoietic stem cell transplant were associated with a more severe disease. Around 90% of the children continued their cancer treatment without any change.

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.

COVID-19 in immunocompromised children: comparison of SARS-CoV-2 viral load dynamics between the first and third waves.

SARS-CoV-2 dynamics across different COVID-19 waves has been unclear in immunocompromised children. We aimed to compare the dynamics of SARS-CoV-2 RNA viral load (VL) during the first and third waves of COVID-19 in immunocompromised children. A retrospective and longitudinal cohort study was conducted in a pediatric referral hospital of Argentina. The study included 28 admitted immunocompromised children with laboratory confirmed SARS-CoV-2 infection. Thirteen acquired the infection during COVID-19 first wave (May to August 2020, group 1 (G1)) and fifteen in the third wave (January to March 2022, group 2 (G2)). RNA viral load measure and its dynamic reconstruction were performed in nasopharyngeal swabs by validated quantitative, real time RT-PCR, and linear mixed-effects model, respectively. Of the 28 children included, 54% were girls, most of them had hemato-oncological pathology (57%), and the median age was 8 years (interquartile range (IQR): 3-13). The dynamic of VL was similar in both groups (P = 0.148), starting from a level of 5.34 log10 copies/mL (95% confidence interval (CI): 4.47-6.21) in G1 and 5.79 log10 copies/mL (95% CI: 4.93-6.65) in G2. Then, VL decayed with a rate of 0.059 (95% CI: 0.038-0.080) and 0.088 (95% CI: 0.058-0.118) log10 copies/mL per day since diagnosis and fell below the limit of quantification at days 51 and 39 after diagnosis in G1 and G2, respectively. Our results evidenced a longer viral RNA persistence in immunocompromised pediatric patients and no difference in VL dynamic between COVID-19 first wave-attributed to ancestral infections-and third wave-attributed to Omicron infections.

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.

Dengue más allá del trópico: estudio de series temporales 2015-2016 versus 2019-2020 en un hospital pediátrico de la Ciudad de Buenos Aires / Dengue beyond the tropics: a time-series study comprising 2015-2016 versus 2019-2020 at a children's hospital in the City of Buenos Aires

Introducción. El dengue es un problema de salud pública a nivel mundial. Confinado en sus orígenes a las zonas tropicales y subtropicales, en la actualidad se presenta en otras regiones como Argentina. Desde el año 2008 se presenta con brotes epidémicos en la Ciudad Autónoma de Buenos Aires, con escasos reportes en niños. Objetivo. Analizar y comparar las características clínicas, epidemiológicas, de laboratorio y evolutivas de los dos últimos brotes de dengue fuera del área endémica. Población y métodos. Estudio de series temporales. Se incluyeron pacientes menores de 18 años con dengue probable o confirmado, evaluados en un hospital pediátrico de la Ciudad de Buenos Aires durante los períodos 2015-2016 y 2019-2020. Resultados. Se incluyeron 239 pacientes, 29 (12 %) con antecedente de viaje. La mediana de edad fue de 132 meses (rango intercuartílico: 102-156). Todos tuvieron fiebre. Otros síntomas fueron: cefalea en 170 (71 %), mialgias en 129 (54 %) y exantema en 122 (51 %). Cuarenta pacientes (17 %) tenían comorbilidades. Presentaron signos de alarma 79 pacientes (33 %) y 14 (6 %) tenían dengue grave. Requirieron internación 115 pacientes (45 %) y ninguno falleció. El serotipo DENV-1 fue el más frecuente. El antecedente de viaje y la necesidad de internación predominaron en el primer período; el dengue grave y la infección previa, en el segundo. Conclusiones. Ningún paciente falleció de dengue en los períodos estudiados. Se observaron diferencias estadísticamente significativas en la frecuencia de internación; el antecedente de viaje fue más frecuente en el período 2015-2016 y el dengue grave, en el 2019-2020.

Introduction. Dengue is a public health problem worldwide. It was originally confined to tropical and subtropical areas, but it is now present in other regions, such as Argentina. Epidemic outbreaks have been observed in the City of Buenos Aires since 2008, with few reports in children. Objective. To analyze and compare the clinical, epidemiological, laboratory, and evolutionary characteristics of the latest 2 dengue outbreaks outside the endemic area. Population and methods. Time-series study. Patients under 18 years of age with probable or confirmed dengue and evaluated in a children's hospital of the City of Buenos Aires during the periods 2015-2016 and 2019-2020 were included. Results. A total of 239 patients were included; 29 (12%) had a history of travel. Their median age was 132 months (interquartile range: 102156). All had a fever. Other symptoms included headache in 170 (71%), myalgia in 129 (54%), and rash in 122 (51%). Forty patients (17%) had comorbidities. Warning signs were observed in 79 patients (33%); 14 (6%) developed severe dengue; 115 (45%) were hospitalized; none died. DENV-1 was the most common serotype. A history of travel and hospitalization prevailed in the first period; severe dengue and prior infection, in the second period. Conclusions. No patient died due to dengue in either study period. Statistically significant differences were observed in the frequency of hospitalization; a history of travel was more common in the 2015-2016 period and severe dengue, in the 2019-2020 period.

Dengue beyond the tropics: a time-series study comprising 2015-2016 versus 2019-2020 at a children's hospital in the City of Buenos Aires. / Dengue más allá del trópico: estudio de series temporales 2015-2016 versus 2019-2020 en un hospital pediátrico de la Ciudad de Buenos Aires.

INTRODUCTION: Dengue is a public health problem worldwide. It was originally confined to tropical and subtropical areas, but it is now present in other regions, such as Argentina. Epidemic outbreaks have been observed in the City of Buenos Aires since 2008, with few reports in children. OBJECTIVE: To analyze and compare the clinical, epidemiological, laboratory, and evolutionary characteristics of the latest 2 dengue outbreaks outside the endemic area. POPULATION AND METHODS: Time-series study. Patients under 18 years of age with probable or confirmed dengue and evaluated in a children's hospital of the City of Buenos Aires during the periods 2015-2016 and 2019-2020 were included. RESULTS: A total of 239 patients were included; 29 (12%) had a history of travel. Their median age was 132 months (interquartile range: 102- 156). All had a fever. Other symptoms included headache in 170 (71%), myalgia in 129 (54%), and rash in 122 (51%). Forty patients (17%) had comorbidities. Warning signs were observed in 79 patients (33%); 14 (6%) developed severe dengue; 115 (45%) were hospitalized; none died. DENV-1 was the most common serotype. A history of travel and hospitalization prevailed in the first period; severe dengue and prior infection, in the second period. CONCLUSIONS: No patient died due to dengue in either study period. Statistically significant differences were observed in the frequency of hospitalization; a history of travel was more common in the 2015-2016 period and severe dengue, in the 2019-2020 period.

Introducción. El dengue es un problema de salud pública a nivel mundial. Confinado en sus orígenes a las zonas tropicales y subtropicales, en la actualidad se presenta en otras regiones como Argentina. Desde el año 2008 se presenta con brotes epidémicos en la Ciudad Autónoma de Buenos Aires, con escasos reportes en niños. OBJETIVO: Analizar y comparar las características clínicas, epidemiológicas, de laboratorio y evolutivas de los dos últimos brotes de dengue fuera del área endémica. Población y métodos. Estudio de series temporales. Se incluyeron pacientes menores de 18 años con dengue probable o confirmado, evaluados en un hospital pediátrico de la Ciudad de Buenos Aires durante los períodos 2015-2016 y 2019-2020. RESULTADOS: Se incluyeron 239 pacientes, 29 (12 %) con antecedente de viaje. La mediana de edad fue de 132 meses (rango intercuartílico: 102-156). Todos tuvieron fiebre. Otros síntomas fueron: cefalea en 170 (71 %), mialgias en 129 (54 %) y exantema en 122 (51 %). Cuarenta pacientes (17 %) tenían comorbilidades. Presentaron signos de alarma 79 pacientes (33 %) y 14 (6 %) tenían dengue grave. Requirieron internación 115 pacientes (45 %) y ninguno falleció. El serotipo DENV-1 fue el más frecuente. El antecedente de viaje y la necesidad de internación predominaron en el primer período; el dengue grave y la infección previa, en el segundo. CONCLUSIONES: Ningún paciente falleció de dengue en los períodos estudiados. Se observaron diferencias estadísticamente significativas en la frecuencia de internación; el antecedente de viaje fue más frecuente en el período 2015-2016 y el dengue grave, en el 2019-2020.

HIV-1 subtype F integrase polymorphisms external to the catalytic core domain contribute to severe loss of replication capacity in context of the integrase inhibitor resistance mutation Q148H.

BACKGROUND: In prior studies, HIV-1 BF recombinants with subtype F integrases failed to develop resistance to raltegravir through the Q148H mutational pathway. We aimed to determine the role of subtype-specific polymorphisms in integrase on drug susceptibility, viral replication and integration. METHODS: Integrase sequences were retrieved from the Los Alamos Database or obtained from the Garrahan HIV cohort. HIV-1 infectious molecular clones with or without Q148H (+ G140S) resistance mutations were constructed using integrases of subtype B (NL4-3) or F1(BF) ARMA159 and URTR23. Integrase chimeras were generated by reciprocal exchanges of a 200 bp fragment spanning amino acids 85-150 of the catalytic core domain (CCD) of NL4-3-Q148H and either ARMA159-Q148H or URTR23-Q148H. Viral infections were quantified by p24 ELISA and Alu-gag integration PCR assay. RESULTS: At least 18 different polymorphisms distinguish subtype B from F1(BF) recombinant integrases. In phenotypic experiments, p24 at Day 15 post-infection was high (105-106 pg/mL) for WT and NL4-3-Q148H; by contrast, it was low (102-104 pg/mL) for both F1(BF)-Q148H + G140S viruses, and undetectable for the Q148H mutants. Compared with WT viruses, integrated DNA was reduced by 5-fold for NL4-3-Q148H (P = 0.05), 9-fold for URTR23-Q148H (P = 0.01) and 16000-fold for ARMA159-Q148H (P = 0.01). Reciprocal exchange between B and F1(BF) of an integrase CCD region failed to rescue the replicative defect of F1(BF) integrase mutants. CONCLUSIONS: The functional impairment of Q148H in the context of subtype F integrases from BF recombinants explains the lack of selection of this pathway in vivo. Non-B polymorphisms external to the integrase CCD may influence the pathway to integrase strand transfer inhibitor resistance.

Making Visible HTLV Infection in a Non-endemic Area of Argentina.

In Argentina, the human T-cell lymphotropic virus type 1 (HTLV-1) infection has been documented mainly among blood banks with a prevalence of ~0.02-0.046% for Buenos Aires city, 0.8% for the northeast, and 1% for the northwest; both areas are considered endemic for HTLV-2 and 1, respectively. Policies and specific guidelines for testing blood donors for HTLV are included since 2005. Screening for antibodies is performed at blood banks and confirmatory testing is performed at reference laboratories. There are no specific recommendations for the assistance of communities and individuals affected, nor referral to specialized clinics on the HTLV infection. In 2016, as a strategy of intervention, we opened a specialized clinical attendance in a referral infectious diseases public hospital for the comprehensive approach to patients with HTLV, offering follow-up and counseling for patients and their families for the early diagnosis of HTLV-1/2 and related diseases. During the study, 124 patients with presumptive HTLV positive diagnosis from blood bank, symptomatic patients (SPs), relatives, and descendants visited the unit. A total of 46 patients were HTLV positive (38 HTLV-1 and 8 HTLV-2). There were nine SPs (2 adult T-cell leukemia/lymphoma [ATL] and 7 HTLV-1-associated myelopathy/tropical spastic paraparesis [HAM/TSP]). All patients with HTLV-1 and-2 were offered to study their relatives. Two out of 37 (5.4%) descendants tested were positive for HTLV-1. Sexual partners were studied; among 6 out of 11 couples (54.5%) were found positive (5 HTLV-1 and 1 HTLV-2). Other relatives, such as mothers (1/2) and siblings (1/6), were positive for HTLV-1. According to the place of birth among HTLV-1 carriers, 58% were born in an endemic area or in countries where HTLV infection is considered endemic while for HTLV-2 carriers, 12.5% were born in an endemic area of Argentina. The proviral load (pVL) was measured in all, patients with HTLV-1 being higher in symptomatic compared with asymptomatic carriers. In addition, two pregnant women were early diagnosed during their puerperium and breastmilk replacement by formula was indicated. Inhibition of lactation was also indicated. Our study provides tools for a multidisciplinary approach to the infection and reinforces the importance of having specialized clinical units in neglected diseases, such as HTLV for counseling, clinical and laboratory follow-up, and providing useful information for patients for self-care and that of their families.

HIV-1 pretreatment drug resistance in vertically infected children is associated with poor virological response to protease inhibitor (PI)-based first-line antiretroviral therapy (ART): results from a cohort study in Argentina.

BACKGROUND: Increasing evidence from adult cohorts suggests an important role of HIV-1 pretreatment drug resistance (PDR) in ART failure, in spite of treatment being fully active according to baseline genotyping tests. Whether this is also true for children is unknown. METHODS: Virological and immunological parameters were longitudinally assessed in a group of 39 HIV-1 vertically infected children starting first-line lopinavir/ritonavir-based ART at a median of 5.0 months (IQR = 3.0-9.0). Evolution of viral load (VL) over time was compared between children with and without baseline PDR, as defined by the WHO mutation list. RESULTS: Resistance-associated mutations (RAMs) in the HIV-1 pol gene were present in nine HIV-1-infected children (23%) before initiation of first-line ART (PDR group). Of them, six carried RAMs associated with NNRTIs (NNRTI-PDR subgroup). At 4-8 weeks after ART initiation, the proportion of children achieving ≥1 log VL reduction was 87% for the no-PDR group versus 33% and 16.7% for the PDR group and the NNRTI-PDR subgroup, respectively. During follow-up, children with no PDR reached virological suppression almost four times faster than children with PDR or NNRTI-PDR [no-PDR = 631 days and PDR = 2134 days (P = 0.1249) and NNRTI-PDR = 2134 days (P = 0.0447)]. CD4 T cells remained similar between the study groups over time. CONCLUSIONS: HIV-1 baseline genotyping at diagnosis in vertically infected children is important for improved personalized medicine. While the mechanism is unclear, cases with PDR (particularly to NNRTIs) require closer monitoring of their first-line ART regimens in order to avoid early virological failures and prevent further accumulation of resistance.

AmpR is a dual regulator in Stenotrophomonas maltophilia with a positive role in ß-lactam resistance and a negative role in virulence, biofilm and DSF production.

Stenotrophomonas maltophilia intrinsic resistance to ß-lactams is mediated by two chromosomal ß-lactamases, L1 and L2, whose induction depends on AmpR. Its quorum sensing (QS) signal, the diffusible signal factor (DSF), has a positive role in biofilm production, virulence and induction of ß-lactamases. We hypothesized that AmpR has a role in virulence, biofilm production and QS system. Studies were done on S. maltophilia K279a, K279a ampRFS (ampR deficient mutant) and K279aM11 (constitutively active AmpR mutant). K279a ampRFS showed the highest biofilm biomass, thickness and 3D organization. Conversely, K279aM11 was the least efficient biofilm former strain. qRT-PCR showed that spgM, related to biofilm formation and virulence, was upregulated in K279a ampRFS and downregulated in K279aM11. A constitutively active AmpR led to a reduction of DSF production, while K279a ampRFS was the highest producer. Consequently, qRT-PCR showed that AmpR negatively regulated rpfF expression. K279a ampRFS presented the highest oxidative stress resistance, overexpressed sodA gene and showed the highest virulence in the Galleria mellonella killing assay. This is the first evidence of the function of AmpR as a dual regulator in S. maltophilia with a positive role in ß-lactam resistance and a negative role in DSF production, biofilm formation, oxidative stress resistance and virulence.

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.

Causes of Microcephaly in the Zika Era in Argentina: A Retrospective Study.

There are gaps in understanding the causes and consequences of microcephaly. This paper describes the epidemiological characteristics, clinical presentations, and etiologies of children presenting microcephaly during the Zika outbreak in Argentina. This observational retrospective study conducted in the pediatric hospital of Juan P. Garrahan reviewed the medical records of 40 children presenting microcephaly between March 2017 and November 2019. The majority (60%) were males and born full-term. At first evaluation, microcephaly was defined as congenital (31/40, 77%) and associated with other features (68%) such as seizures, developmental delay, non-progressive chronic encephalopathy, and West Syndrome. It was found manifestations restricted to central nervous system (55%), ocular (8/40, 20%), and acoustic (9/40, 23%) defects, and abnormal neuroimaging findings (31/39, 79%). Non-infectious diseases were the primary cause of isolated microcephaly (21/37, 57%), largely related to genetic diseases (13/21, 62%). Only 3 were children were diagnosed with Congenital Zika infection (3/16, 7.5%).

Corrigendum to Antiviral effect of high-dose ivermectin in adults with COVID-19: A proof-of-concept randomized trial [EClinicalMedicine 37 (2021) 100,959]".

[This corrects the article DOI: 10.1016/j.eclinm.2021.100959.].

A new highly sensitive single-tube nested real-time PCR assay: Clinical utility in perinatal HIV-1 diagnosis.

Real time PCR is one of the major tools for molecular diagnosis, however not always reaches the required sensitivity, especially in detecting early infectious disease. To overcome this problem, nested PCR is commonly performed, since it is highly sensitive, but it is time-consuming, prone to cross-contamination and difficult to standardize. Therefore, we developed a sensitive and specific single-tube nested real-time PCR (STN-real-time PCR) assay and evaluated its clinical utility on early infant HIV-1 diagnosis (EID). The STN-real-time PCR enables the simultaneous amplification of four HIV-1 specific amplicons by the use of an internal and external pair of primers targeting ltr/gag region, and another one corresponding to human albumin as an internal control. Thermocycling had different annealing temperatures to favor the sequential use of each pair of primers, and included an initial touchdown step to broaden specificity and increase sensitivity. Finally, HIV-1 was detected by melting curve analysis. A total of 234 samples collected retrospectively and prospectively from HIV-1 exposed infants aged <18 months were used to evaluate the performance of the assay and compare it with a routine diagnostic nested-multiplex PCR. The developed assay had a limit of detection of 3 copies of HIV-1 DNA per reaction and had a sensitivity of 31 % more than routine diagnostic nested-multiplex PCR when testing samples near delivery. In conclusion, we developed a new assay by turning a conventional nested-PCR into a faster, more sensitive and feasible STN-real-time PCR assay for EID and potentially useful for detection of pathogens with variable genomes and present in low copy numbers.

Antiviral effect of high-dose ivermectin in adults with COVID-19: A proof-of-concept randomized trial.

BACKGROUND: There are limited antiviral options for the treatment of patients with COVID-19. Ivermectin (IVM), a macrocyclic lactone with a wide anti-parasitary spectrum, has shown potent activity against SARS-CoV-2 in vitro. This study aimed at assessing the antiviral effect of IVM on viral load of respiratory secretions and its relationship with drug concentrations in plasma. METHODS: Proof-of-concept, pilot, randomized, controlled, outcome-assessor blinded trial to evaluate antiviral activity of high-dose IVM in 45 COVID-19 hospitalized patients randomized in a 2:1 ratio to standard of care plus oral IVM at 0·6 mg/kg/day for 5 days versus standard of care in 4 hospitals in Argentina. Eligible patients were adults with RT-PCR confirmed SARS-CoV-2 infection within 5 days of symptoms onset. The primary endpoint was the difference in viral load in respiratory secretions between baseline and day-5, by quantitative RT-PCR. Concentrations of IVM in plasma were measured. Study registered at ClinicalTrials.gov: NCT04381884. FINDINGS: 45 participants were recruited (30 to IVM and 15 controls) between May 18 and September 9, 2020. There was no difference in viral load reduction between groups but a significant difference was found in patients with higher median plasma IVM levels (72% IQR 59-77) versus untreated controls (42% IQR 31-73) (p = 0·004). Mean ivermectin plasma concentration levels correlated with viral decay rate (r: 0·47, p = 0·02). Adverse events were similar between groups. No differences in clinical evolution at day-7 and day-30 between groups were observed. INTERPRETATION: A concentration dependent antiviral activity of oral high-dose IVM was identified at a dosing regimen that was well tolerated. Large trials with clinical endpoints are necessary to determine the clinical utility of IVM in COVID-19. FUNDING: This work was supported by grant IP-COVID-19-625, Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación, Argentina and Laboratorio ELEA/Phoenix, Argentina.

Unraveling HIV-1 diagnosis in special pediatric cases.

BACKGROUND: Early HIV-1 diagnosis and initiation of antiretroviral treatment is essential to prevent AIDS, and reduce mortality in children. HIV-1 molecular diagnosis in children before 18 months of age require, two independent samples to confirm a result. However, some patients have discordant virologic results in different samples, raising uncertainty for a conclusive diagnosis. We defined these patients as "special pediatric cases". OBJECTIVES: The aim of our study was to characterize the "special pediatric cases" among HIV-1 infected children diagnosed in a five-year period at our laboratory and evaluate the impact on the time to HIV-1 diagnosis. STUDY DESIGN: A total of 44 perinatally HIV-1 infected infants with molecular diagnostic performed at the Pediatric Garrahan Hospital were analyzed from 2013 to 2017. RESULTS: We identified eight "special pediatric cases". In the first samples, all of them had negative results by different DNA-PCR assays. Three infants had undetectable plasma viral load (pVL), four had low detectable pVL value, and one infant had no available pVL. All samples with detectable pVL, including those with low pVL (ie: 65copies/mL), had high pVL values at the end of the diagnosis. Considering the age of the HIV-1 infected children at the end of the diagnosis, five "special pediatric cases" (62 %) had a "late" positive diagnosis [mean (range) = 146 (89-268) days old]. CONCLUSIONS: These "special pediatric cases" are not as unusual as previously thought and are important diagnostic challenges. Also, this study add evidence to include the viral load assay in the molecular diagnostic algorithm for perinatal HIV-1 infection.

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.

Impact of genotypic diversity on selection of subtype-specific drug resistance profiles during raltegravir-based therapy in individuals infected with B and BF recombinant HIV-1 strains.

BACKGROUND: Current knowledge on HIV-1 resistance to integrase inhibitors (INIs) is based mostly on subtype B strains. This contrasts with the increasing use of INIs in low- and middle-income countries, where non-B subtypes predominate. MATERIALS AND METHODS: HIV-1 drug resistance genotyping was performed in 30 HIV-1-infected individuals undergoing virological failure to raltegravir. Drug resistance mutations (DRMs) and HIV-1 subtype were characterized using Stanford HIVdb and phylogenetic analyses. RESULTS: Of the 30 integrase (IN) sequences, 14 were characterized as subtype F (47%), 8 as subtype B (27%), 7 as BF recombinants (23%) and 1 as a putative CRF05_DF (3%). In 25 cases (83%), protease and reverse transcriptase (PR-RT) sequences from the same individuals confirmed the presence of different BF recombinants. Stanford HIVdb genotyping was concordant with phylogenetic inference in 70% of IN and 60% of PR-RT sequences. INI DRMs differed between B and F IN subtypes, with Q148K/R/H, G140S and E138K/A being more prevalent in subtype B (63% versus 0%, P = 0.0021; 50% versus 0%, P = 0.0096; and 50% versus 0%, P = 0.0096, respectively). These differences were independent of the time on raltegravir therapy or viral load at the time of genotyping. INI DRMs in subtype F IN genomes predicted a lower level of resistance to raltegravir and no cross-resistance to second-generation INIs. CONCLUSIONS: Alternative resistance pathways to raltegravir develop in subtypes B and F IN genomes, with implications for clinical practice. Evaluating the role of HIV-1 subtype in development and persistence of mutations that confer resistance to INIs will be important to improve algorithms for resistance testing and optimize the use of INIs.