Deep immunophenotyping reveals biomarkers of MIS-C in a Latin American cohort

Background

Multisystemic inflammatory syndrome in children (MIS-C) is a life-threatening disease that occurs 2-5 weeks after SARS-CoV-2 exposure and is characterized by severe multisystemic inflammation. Early recognition of MIS-C is key to prognosis, therefore establishing clinical and laboratory biomarkers that predict complications is urgently needed.

Objective

To characterize the immune response and clinical features of patients with acute MIS-C and determine biomarkers of disease in a cohort of 42 Latin American patients.

Methods

Immune characterization was performed using flow cytometry from peripheral mononuclear cells and SARS-CoV-2-specific humoral and cellular response was performed using flow cytometry, ELISPOT, ELISA and neutralizing antibody assays.

Results

MIS-C is characterized by robust T cell activation and cytokine storm. We uncovered that while CXCL9, IL-10, CXCL8, CXCL10, IL-6 and IL-18 are significantly elevated in patients with shock, while CCL5 was increased in milder disease. Monocyte dysregulation was specifically associated to Kawasaki-like MIS-C. Interestingly, MIS-C patients show an NK cell degranulation defect that is persistent after 6 months of disease presentation, suggesting it could underlie disease susceptibility. Most MIS-C had gastrointestinal involvement and higher levels of neopterin were identified in their stools, potentially representing a biomarker of intestinal inflammation in MIS-C. SARS-CoV2-specific cellular response and neutralizing antibodies were identifiable in convalescent MIS-C patients suggesting sustained immunity.

Conclusion

Clinical characterization and comprehensive immunophenotyping of Chilean MIS-C cohort provide valuable insights in understanding immune dysregulation in MIS-C and identify relevant biomarkers of disease that could be used to predict severity and organ involvement.

CLINICAL IMPLICATIONS STATEMENT

MIS-C is distinguished by cytokine storm and decreased NK cell degranulation that is persistent after 6 months. Distinct biomarkers were identified for severe and mild forms of disease.

[Recommendations for the suspected diagnosis and management of Multisystemic Inflammatory Syndrome (MIS-C) in the context of a SARS-CoV-2 pandemic. April 2021]

Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) is a post-infectious complication described in children and adolescents with previous exposure to SARS-CoV-2. Because of its potential to evolve to severe disease -including cardiovascular impairment and multiple organ failure it requires a prompt diagnosis and appropriate management, including intensive care for most cases. These guidelines compile recent information from scientific literature, from our local clinical experiences during the past pandemic year, and have been discussed by experts. The recommendations provided are meant to help the clinical work of health teams attending the pediatric population.

Hematologic parameters and biomarkers predictors of severity in Multisystem Inflammatory Syndrome in children associated with SARS-CoV-2

INTRODUCTION

The multisystem inflammatory syndrome in children associated with SARS-CoV-2 (MIS-C) is cha racterized by a hyperinflammatory state resulting from a cytokine storm, evidenced by alterations in laboratory blood testing and acute-phase proteins.

OBJECTIVE

to describe the clinical and labora tory characteristics of patients hospitalized due to MIS-C and identify predictive markers of severity.

PATIENTS AND METHOD

Retrospective study of 32 patients. The group was divided into critical and non-critical according to clinical presentation and therapy used. Clinical and laboratory aspects were studied, including complete blood count, coagulation tests, and biomarkers.

RESULTS

18/32 were males, with a median age of 6.8 years. The most frequent manifestations were cardiovascular (84.3%), digestive (84%), and mucocutaneous (59%). The group of critical patients included 15 patients, 12 were males with a median age of 8.9 years, and the non-critical group included 17 patients, 6 were males with a median age of 5.4 years. The laboratory parameters at the admission in the global group showed increased C-reactive protein, D-dimer, leukocytes, neutrophils, ferritin, and fibrinogen. In contrast, albumin and blood sodium levels were decreased. At admission, the critical group was cha racterized by presenting thrombocytopenia, hypoalbuminemia, prolonged prothrombin time, and elevated ferritin. At the time of deterioration, there was an intensification of thrombocytopenia, in creased C-reactive protein together with increased neutrophils level.

CONCLUSION

The blood count, C-reactive protein, and albuminemia at admission proved to be significantly important in the identi fication of patients at risk of clinical deterioration.

[Clinical manifestations of SARS-CoV-2 infection in children in the middle of pandemic season in a pediatric tertiary center. Report of local COVID Clinical Committee, Hospital de Niños Roberto del Río, Santiago Chile]

BACKGROUND

SARS-CoV-2 virus infection responsible for de pandemic in course, is a new clinical and physiopathological entity, whose control is still uncertain till we can provide an effective and universal vaccine. In the beginning it was described as a respiratory disease which affects mainly adults, children can have the disease too and in this group the disease can be different than the adult disease. Acute infection in children is mostly mild and when it requires hospital assistance it resolves with support therapy and without complications most of the time. However, in the Pediatric Inflammatory Multisystemic Syndrome is vital the early clinical suspect and refers to a tertiary center to bring support and properly treatment.

AIM

To describe the clinical spectrum of SARS-CoV-2 virus disease in a pediatric referral center with the pandemic still in development.

METHOD

A case series of 537 patients with SARS-CoV-2 infection treated between March 1 and July 15, 2020 is presented with a description of those who were hospitalized.

RESULTS

127 (23%) of them were hospitalized and of these 69% were symptomatic. Twenty-six patients (20%) of those hospitalized presented PIMS, only one died for complications of his chronic diseases.

A comparison of mosquito densities, weather and infection rates of Aedes aegypti during the first epidemics of Chikungunya (2014) and Zika (2016) in areas with and without vector control in Puerto Rico

In Puerto Rico, the first records of the transmission of Chikungunya (CHIKV) and Zika (ZIKV) viruses were confirmed in May 2014 and December 2015, respectively. Transmission of CHIKV peaked in September 2014, whereas that of ZIKV peaked in August 2016. The emergence of these mosquito-transmitted arboviruses in the context of a lack of human population immunity allowed observations of whether the outbreaks were associated with Aedes aegypti (Diptera: Culicidae) densities and weather. Mosquito density was monitored weekly in four communities using sentinel autocidal gravid ovitraps (AGO traps) during 2016 in order to provide data to be compared with the findings of a previous study carried out during the 2014 CHIKV epidemic. Findings in two communities protected against Ae. aegypti using mass AGO trapping (three traps per house in most houses) were compared with those in two nearby communities without vector control. Mosquito pools were collected to detect viral RNA of ZIKV, CHIKV and dengue virus. In areas without vector control, mosquito densities and rates of ZIKV detection in 2016 were significantly higher, similarly to those observed for CHIKV in 2014. The density of Ae. aegypti in treated sites was less than two females/trap/week, which is similar to the putative adult female threshold for CHIKV transmission. No significant differences in mosquito density or infection rates with ZIKV and CHIKV at the same sites between years were observed. Although 2016 was significantly wetter, mosquito densities were similar.

X-ray diffraction and Raman spectroscopy study of white decorations on tricolored ceramics from Northwestern Argentina

White virgules, commas, and dot designs on tricolored ceramics are sporadically found in different archaeological sites located in Northwestern Argentina area, as Puna and Quebrada de Humahuaca. This decorating style has been reported in several articles, but few previous archaeometric studies have been carried out on the pigment composition. Fragments from Puna and Quebrada archaeological sites, belonging to Regional Development Period (900-1430 AD), were analyzed by X-ray diffraction and Raman spectroscopy in order to characterize the pigments employed. Red and black pigments are based on iron and manganese oxides, as it has been extensively reported for the NW Argentina area. White pigments from white virgules, comma, and dot designs have shown different composition. Hydroxyapatite was found in samples from Doncellas site (North Puna region), and calcium and calcium-magnesium containing compounds, as vaterite and dolomite, along with titanium containing compounds were detected on samples from Abralaite (Central Puna region) and Gasoducto (Quebrada de Humahuaca region). It has been concluded that pigment composition is not characteristic of a unique region.

First Report of Squash vein yellowing virus Affecting Watermelon and Bitter Gourd in Puerto Rico

In 2005, symptoms of watermelon vine decline (WVD) were observed on a 200-acre watermelon farm in Santa Isabel, on the south central coast of Puerto Rico. WVD symptoms included leaf curling, mosaics, and internode necrosis. In early growth stages of WVD, reduced vigor and plant stunting occurred. At flowering, symptoms progressed to necrosis and wilting of vines. A 2006 to 2007 survey demonstrated that fungal pathogens were not associated with the presence of WVD symptoms (3,4). By 2006, other watermelon fields were also affected. Field trials in 2007 and 2008 with insect-proof cages and insecticides suggested a role of whiteflies (Bemisia tabaci) in the transmission of a virus (3,4). Here, we report that watermelon and pumpkin plants were successfully infected in Puerto Rico by mechanical inoculation and through B. tabaci transmission assays, similarly to transmissions previously conducted in Florida with Squash vein yellowing virus (SqVYV) (1). In addition, plants of Cucurbita moschata exhibited vein clearing symptoms typical of SqVYV after mechanical inoculation with extracts from watermelon plants with WVD symptoms. In 2011, eight watermelon samples from plants exhibiting WVD syndrome were collected in Guánica, Santa Isabel, Juana Díaz, and Mayagüez, and two Momordica charantia samples were collected from Mayagüez. RNA was extracted from all 10 original samples, as well as from plants that were used in mechanical and vector transmission assays, using RNeasy Plant Mini Kit (Qiagen, Valencia, California), and all samples were found positive for SqVYV by reverse transcription-PCR, using previously described primers and methods (1,2). In all cases, a single ~1-kb PCR fragment was revealed, and PCR fragments from four samples were selected for direct sequencing. All sequences showed high levels (>99%) of nucleotide identity with SqVYV sequences from Florida (JF897989, JF897985, and JF897984). Sequences of the SqVYV CP gene from Puerto Rico were deposited in GenBank under accession numbers KC713961 to KC713964. To our knowledge, this is the first report of SqVYV in Puerto Rico associated with WVD syndrome in cucurbits, and thus has implications for management of viral diseases of watermelon in the Caribbean. This is also the first detection of SqVYV outside of the continental United States in both watermelon and a wild species, M. charantia (bitter gourd). References: (1) S. Adkins et al. Phytopathology 97:145, 2007. (2) S. Adkins et al. Plant Dis. 92:1119, 2008. (3) C. Estévez de Jensen et al. Phytopathology 98:S52, 2008. (4) L. Polanco-Florián. El marchitamiento súbito de la sandía [Citrullus lanatus (Thumb.) Matsum & Nakai]. M.S. thesis, University of Puerto Rico, Mayagüez, PR, 2009.

Mosquito vectors of West Nile virus during an epizootic outbreak in Puerto Rico

The purpose of this investigation was to identify the mosquito (Diptera: Culicidae) vectors of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) during an epizootic WNV outbreak in eastern Puerto Rico in 2007. In June 2006, 12 sentinel chicken pens with five chickens per pen were deployed in six types of habitats: herbaceous wetlands, mangrove forests, deciduous forests, evergreen forests, rural areas, and urban areas. Once WNV seroconversion in chickens was detected in June 2007, we began trapping mosquitoes using Centers for Disease Control and Prevention (CDC) miniature (light/CO2-baited) traps, CMT-20 collapsible mosquito (CO2- and ISCA SkinLure-baited) traps, and CDC gravid (hay infusion-baited) traps. We placed the CDC miniature traps both 2-4 m and >30 m from the chicken pens, the collapsible traps 2-4 m from the pens, and the gravid traps in backyards of houses with sentinel chicken pens and in a wetland adjacent to an urban area. We found numerous blood-engorged mosquitoes in the traps nearest to the sentinel chickens and reasoned that any such mosquitoes with a disseminated WNV infection likely served as vectors for the transmission of WNV to the sentinels. We used reverse transcriptase-polymerase chain reaction and isolation (C636) on pools of heads, thoraxes/ abdomens, and legs of collected blood-engorged mosquitoes to determine whether the mosquitoes carried WNV. We detected WNV-disseminated infections in and obtained WNV isolates from Culex nigripalpus Theo (minimum infection rate [MIR] 1.1-9.7/1,000), Culex bahamensis Dyar and Knab (MIR 1.8-6.0/1,000), and Aedes taeniorhynchus (Wied.) (MIR 0.34-0.36/1,000). WNV was also identified in and isolated from the pool of thoraxes and abdomens of Culex quinquefasciatus Say (4.17/1,000) and identified in one pool of thoraxes and abdomens of Culex habilitator Dyar and Knab (13.39/1,000). Accumulated evidence since 2002 suggests that WNV has not become endemic in Puerto Rico.

Intravenous Amiodarone for Incessant Tachyarrhythmias in Children

Background— Intravenous (IV) amiodarone has proven efficacy in adults. However, its use in children is based on limited retrospective data.

Methods and Results— A double-blind, randomized, multicenter, dose-response study of the safety and efficacy of IV amiodarone was conducted in 61 children (30 days to 14.9 years; median, 1.6 years). Children with incessant tachyarrhythmias (supraventricular arrhythmias [n=26], junctional ectopic tachycardia [JET, n=31], or ventricular arrhythmias [n=4]) were randomized to 1 of 3 dosing regimens (low, medium, or high: load plus 47-hour maintenance) with up to 5 open-label rescue doses. The primary efficacy end point was time to success. Of 229 patients screened, 61 were enrolled during 13 months by 27 of 48 centers in 7 countries. Median time to success was significantly related to dose (28.2, 2.6, and 2.1 hours for the low-, medium-, and high-dose groups, respectively; P =0.028). There was no significant association with dose for any arrhythmia subgroup, including JET, but the subgroups were too small for an accurate assessment. Adverse events (AEs) were common (87%), leading to withdrawal of 10 patients. There were 5 deaths in the 30-day follow-up period (2 possibly related to the study drug). Dose-related AEs included hypotension (36%), vomiting (20%), bradycardia (20%), atrioventricular block (15%) and nausea (10%).

Conclusions— In children, the overall efficacy of IV amiodarone, as measured by time to success, was dose related but not significantly for any arrhythmia subgroup. AEs were common and appeared to be dose related. Although efficacious for critically ill patients, the dose-related risks of IV amiodarone should be taken into account when treating children with incessant arrhythmias. Prospective, placebo-controlled trials would be helpful in assessing antiarrhythmic drug efficacy in children, because their results may differ from retrospective series and adult studies.

Preterm infants with paroxysmal supraventricular tachycardia: presentation, response to therapy, and outcome

OBJECTIVES

We investigated the clinical course of preterm infants with paroxysmal supraventricular tachycardia in comparison to their term counterparts.

BACKGROUND

Paroxysmal supraventricular tachycardia (PSVT) is the most common arrhythmia in childhood. It is known to cause significant morbidity and rarely mortality, most commonly in infants. Yet, there is minimal information in the literature on preterm infants with PSVT.

METHODS

Retrospective review of 40 infants, 26 term and 14 preterm, less than three months of age who presented with PSVT from January 1990 to January 1999. We compared the severity of first clinical presentation, in-hospital response to long-term medications, and outcome after discharge.

RESULTS

Symptomatic severity on presentation was not different between preterm and term infants. Preterm infants required fewer medication trials (p=0.01) and had no recurrences after discharge in contrast with 43 % recurrence in the term infants (p<0.0001). No preterm infants had Wolff-Parkinson-White syndrome (WPW) in contrast to 42 % of term infants (p=0.003). Term infants with WPW were more symptomatic (p=0.01), required more medications (p=0.004), but had a similar recurrence frequency as terms infants without WPW (p=0.95). Excluding infants with WPW, preterm infants were more severely symptomatic (p=0.02), yet no longer was there a difference in response to first medication trial (p=0.30).

CONCLUSIONS

We found that preterm infants with PSVT are as severely symptomatic on presentation, require fewer medications for adequate in-hospital control, and have fewer recurrences than their term counterparts. Unexpectedly, preterm infants did not present with WPW. The presence of WPW only in the term infants may account for differences in the clinical course between preterm and term infants.

Comparison of three transport systems (Starplex StarSwab II, the new Copan Vi-Pak Amies Agar Gel collection and transport swabs, and BBL Port-A-Cul) for maintenance of anaerobic and fastidious aerobic organisms

Of utmost importance in evaluations of clinical samples for infectious agents is proper specimen transport to the clinical laboratory. In the present study we compared three transport systems (the new Starplex StarSwab II, the new Copan Vi-Pak Amies Agar Gel collection and transport swabs, and the BBL Port-A-Cul) for survival of anaerobic and fastidious aerobic bacteria. The new Copan Vi-Pak system has been modified by nitrogen gas flushing to keep an ideal low E(h) condition and to prevent oxidation of the transport medium. The Copan Vi-Pak system outperformed the other two swabs evaluated by maintaining the viabilities of both anaerobic and fastidious aerobic bacteria for 24 h for the majority of the organisms evaluated. This time period should be sufficient for transport of specimens to the clinical microbiology laboratory without compromising organism recovery.

[Radiofrequency fulguration for supraventricular tachycardia in pediatrics]

Supraventricular tachycardias (SVT) are the most frequent cause of tachycardia in children. Its pharmacological treatment has adverse effects, is not curative, and is not always effective. During the last few years radiofrequency ablation (RF-A) has changed the treatment. The purpose of this study is to evaluate our experience in RF-A in children with SVT. Between 1990 and 1995, 92 patients (1 month to 17 years old) underwent electrophysiological study after the diagnosis of SVT. RF-A was attempted in 55 patients with accessory pathways (AP), slow-pathway of the atrioventricular node, or ectopic focus. The site of ablation was decided according to the electrical signals and the catheter position. The success of the RF-A was confirmed by the interruption of the tachycardia, the change in the sequence of activation of the intracardiac signals, the regression of the preexcitation, and the inability to reinduce tachycardia. RF-A was successful in 81% of the patients; 88% in those with a left AP, 56% in those with a right AP, and 100% in those with nodal reentry. Complications were seen in 7% of the patients: 3 with arterial obstruction, one with a minimal pneumothorax, and one with cardiac tamponade. During a follow up of 16.6 months there was no relapse nor late complications. We conclude that RF-A is a safe and effective procedure in pediatric patients with SVT.

Experimental vaccine protection against homologous and heterologous strains of feline immunodeficiency virus

More than 90% of cats immunized with inactivated whole infected-cell or cell-free feline immunodeficiency virus (FIV) vaccines were protected against intraperitoneal infection with 10 50% animal infectious doses of either homologous FIV Petaluma (28 of 30 cats) or heterologous FIV Dixon strain (27 of 28 cats). All 15 control cats were readily infected with either strain of FIV. Protection appears to correlate with antiviral envelope antibody levels by a mechanism yet to be determined.