Pandemic (H1N1) 2009 virus and Down syndrome patients

Choroid plexus defects in Down syndrome brain organoids enhance neurotropism of SARS-CoV-2

Why individuals with Down syndrome (DS) are more susceptible to SARS-CoV-2-induced neuropathology remains elusive. Choroid plexus (ChP) plays critical roles in barrier function and immune response modulation and expresses the ACE2 receptor and the chromosome 21-encoded TMPRSS2 protease, suggesting its substantial role in establishing SARS-CoV-2 infection in the brain. To explore this, we established brain organoids from DS and isogenic euploid iPSC that consist of a core of functional cortical neurons surrounded by a functional ChP-like epithelium (ChPCOs). DS-ChPCOs recapitulated abnormal DS cortical development and revealed defects in ciliogenesis and epithelial cell polarity in ChP-like epithelium. We then demonstrated that the ChP-like epithelium facilitates infection and replication of SARS-CoV-2 in cortical neurons and that this is increased in DS. Inhibiting TMPRSS2 and furin activity reduced viral replication in DS-ChPCOs to euploid levels. This model enables dissection of the role of ChP in neurotropic virus infection and euploid forebrain development and permits screening of therapeutics for SARS-CoV-2-induced neuropathogenesis.

Altered peripheral blood leukocyte subpopulations, function, and gene expression in children with Down syndrome: implications for respiratory tract infection

OBJECTIVES

We tested the hypothesis that aberrant expression of Hsa21-encoded interferon genes in peripheral blood immune cells would correlate to immune cell dysfunction in children with Down syndrome (DS).

STUDY DESIGN

We performed flow cytometry to quantify peripheral blood leukocyte subtypes and measured their ability to migrate and phagocytose. In matched samples, we measured gene expression levels for constituents of interferon signaling pathways. We screened 49 children, of which 29 were individuals with DS.

RESULTS

We show that the percentages of two peripheral blood myeloid cell subtypes (alternatively-activated macrophages and low-density granulocytes) in children with DS differed significantly from typical children, children with DS circulate a very different pattern of cytokines vs. typical individuals, and higher expression levels of type III interferon receptor Interleukin-10Rb in individuals with DS correlated with reduced migratory and phagocytic capacity of macrophages.

CONCLUSIONS

Increased susceptibility to severe and chronic infection in children with DS may result from inappropriate numbers and subtypes of immune cells that are phenotypically and functionally altered due to trisomy 21 associated interferonopathy.

The immune system in Down Syndrome: Autoimmunity and severe infections

Over 200,000 individuals in the United States alone live with Down Syndrome (DS), the most common genetic disorder associated with intellectual disability. DS has a constellation of features across the body, including dysregulation of the immune system. Individuals with DS have both a higher frequency of autoimmunity and more severe infections than the general population, highlighting the importance of understanding the immune system in this population. Individuals with DS present with dysregulation of both the innate and adaptive immune systems. Elevated cytokine levels, increased type I and type II IFN signaling, a shift toward memory phenotypes in T cells, and a decrease in the size of the B-cell compartment are observed in individuals with DS, which contribute to both autoinflammation and severe infections. Herein, we discuss the current knowledge of the immune system in individuals with Down Syndrome as well as ideas of necessary further investigations to decipher the mechanisms by which trisomy 21 leads to immune dysregulation, with the ultimate goal of identifying clinical targets to improve treatment.

Clinical profile of influenza virus-related hospitalizations in children aged 1-59 months: A five-year retrospective study from south India

BACKGROUND

Influenza is a seasonal acute respiratory tract infection with different strains in circulation at different time periods with varying spectrum of clinical presentation.

OBJECTIVES

To study the clinical presentation, morbidity, and mortality patterns associated with different strains of influenza virus, to identify the predominant strains related to hospitalization, and to identify the seasonal trend in hospitalization and risk factors for mortality in children aged 1-59 months hospitalized with influenza.

MATERIALS AND METHODS

The records of children hospitalized with influenza were analyzed retrospectively (June 2013 to June 2018). Anonymized data from the Medical Records Department of our Institute, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), were used for the study and waiver of consent was obtained from the Institute Ethics Committee for Human Studies (JIPMER), which also approved the study. The data from the medical records were extracted as per the proforma and entered into Microsoft excel and summary statistics was obtained. Categorical data were expressed as proportion and analyzed using chi square test. Association was tested using odds ratio.

RESULTS

Of the 693 children tested for influenza during the study period, 91 were found to be positive for influenza infection and out of which 68 (74.7%) were hospitalized. Infection was seen during both the summer and winter months. The predominant strain being A (H1N1) pdm09 (63.2%). The other strains found were A (H3N2) and Influenza B. The predominant diagnosis was pneumonia. The need for mechanical ventilation was more common with influenza B infection (p = 0.035). No significant risk factors for mortality could be found in our study.

CONCLUSION

An absence of seasonal predilection for the disease was noted with influenza A (H1N1) pdm09 being the predominant strain with influenza B seen as an emerging strain and an important contributor towards morbidity.

Incidence and clinical outcomes of pneumonia in persons with down syndrome in the United States

BACKGROUND

Persons with Down syndrome (DS) experience an increased risk of pneumonia. We determined the incidence and outcomes of pneumonia and relationship to underlying comorbidities in persons with and without DS in the United States.

METHODS

This retrospective matched cohort study used de-identified administrative claims data from Optum. Persons with DS were matched 1:4 to persons without DS on age, sex, and race/ethnicity. Pneumonia episodes were analyzed for incidence, rate ratios and 95 % confidence intervals, clinical outcomes, and comorbidities.

RESULTS

During 1-year follow-up among 33796 persons with and 135184 without DS, the incidence of all-cause pneumonia (pneumonia) was substantially higher among people with DS than those without DS (12427 vs. 2531 episodes/100000 person-years; 4.7-5.7 fold increase). Persons with DS and pneumonia were more likely to be hospitalized (39.4 % vs. 13.9 %) or admitted to the ICU (16.8 % vs. 4.8 %). Mortality was higher 1 year after first pneumonia (5.7 % vs. 2.4 %; P < 0.0001). Results were similar for episodes of pneumococcal pneumonia. Specific comorbidities were associated with pneumonia, particularly heart disease in children and neurologic disease in adults, which only partially mediated the effect of DS on pneumonia.

CONCLUSIONS

Among persons with DS, incidence of pneumonia and associated hospitalizations were increased; mortality among those with pneumonia was comparable at 30 days, but higher at 1 year. DS should be considered an independent risk condition for pneumonia.

Seasonal influenza vaccine uptake among adults with disabilities in Korea

BACKGROUND

Previous research on vaccination among people with disabilities has focused on children or adolescents.

OBJECTIVE

To examine variations in seasonal influenza vaccination (SIV) uptake according to disability type and age group and explore the vulnerable groups and risk factors of non-vaccination to identify areas of policy support in Korea.

METHODS

This pooled cross-sectional study included adults who participated in the 2011, 2014, and 2017 National Survey of Persons with Disabilities. The dependent variable was SIV uptake. Age-stratified multivariate logistic regression was conducted to assess its relationship with disability characteristics.

RESULTS

Among 18,069 adults with disabilities, the overall SIV uptake rate increased with age (33.8%, 50.1%, and 85.3% in 20-49, 50-65, and ≥65 years, respectively). In the multivariate analyses (reporting the adjusted odds ratio and 95% confidence interval), severe disability was associated with lower and higher SIV uptake rates in older adults and younger age-groups (0.88, 0.76-1.01; 1.62, 1.42-1.86; and 1.54, 1.24-1.92 in those aged ≥65; 50-64; and 20-49 years), respectively. Health behaviors (regular doctor visits, general health examinations, and non-smoking) were significantly associated with higher odds of SIV uptake. After adjusting for covariates (age, medical conditions, functional ability, and behavioral factors), individuals with brain, epileptic, and psychiatric disabilities showed lower odds of SIV uptake compared to those with internal organ disabilities across all age groups.

CONCLUSIONS

Policy initiatives that can improve the health behaviors of people with disabilities (especially the elderly and people with intellectual, brain, epilepsy, and psychiatric disabilities) to promote SIV uptake are needed.

Excessive negative regulation of type I interferon disrupts viral control in individuals with Down syndrome

Down syndrome (DS) is typically caused by triplication of chromosome 21. Phenotypically, DS presents with developmental, neurocognitive, and immune features. Epidemiologically, individuals with DS have less frequent viral infection, but when present, these infections lead to more severe disease. The potent antiviral cytokine type I Interferon (IFN-I) receptor subunits IFNAR1 and IFNAR2 are located on chromosome 21. While increased IFNAR1/2 expression initially caused hypersensitivity to IFN-I, it triggered excessive negative feedback. This led to a hypo-response to subsequent IFN-I stimuli and an ensuing viral susceptibility in DS compared to control cells. Upregulation of IFNAR2 expression phenocopied the DS IFN-I dynamics independent of trisomy 21. CD14+ monocytes from individuals with DS exhibited markers of prior IFN-I exposure and had muted responsiveness to ex vivo IFN-I stimulation. Our findings unveil oscillations of hyper- and hypo-response to IFN-I in DS, predisposing individuals to both lower incidence of viral disease and increased infection-related morbidity and mortality.

COVID-19 hospitalization with later long COVID in a person with Down syndrome

Viruses that induce pulmonary difficulties and auto-inflammation are more common in people with Down syndrome. They also have a higher number of comorbidities associated with a worse prognosis than the overall population. Adult patients with acute COVID-19 are increasingly being diagnosed with Long COVID. However, patients with Down syndrome with later long COVID-19 are the first example documented in Bangladesh.

Pandemics, past and present: The role of biological anthropology in interdisciplinary pandemic studies

Biological anthropologists are ideally suited for the study of pandemics given their strengths in human biology, health, culture, and behavior, yet pandemics have historically not been a major focus of research. The COVID‐19 pandemic has reinforced the need to understand pandemic causes and unequal consequences at multiple levels. Insights from past pandemics can strengthen the knowledge base and inform the study of current and future pandemics through an anthropological lens. In this paper, we discuss the distinctive social and epidemiological features of pandemics, as well as the ways in which biological anthropologists have previously studied infectious diseases, epidemics, and pandemics. We then review interdisciplinary research on three pandemics–1918 influenza, 2009 influenza, and COVID‐19–focusing on persistent social inequalities in morbidity and mortality related to sex and gender; race, ethnicity, and Indigeneity; and pre‐existing health and disability. Following this review of the current state of pandemic research on these topics, we conclude with a discussion of ways biological anthropologists can contribute to this field moving forward. Biological anthropologists can add rich historical and cross‐cultural depth to the study of pandemics, provide insights into the biosocial complexities of pandemics using the theory of syndemics, investigate the social and health impacts of stress and stigma, and address important methodological and ethical issues. As COVID‐19 is unlikely to be the last global pandemic, stronger involvement of biological anthropology in pandemic studies and public health policy and research is vital.

Adults with Trisomy 21 Have Differential Antibody Responses to Influenza A

Down syndrome is caused by an extra copy of chromosome 21. In the past two decades, the life expectancy of individuals with Down syndrome has significantly increased from early 20s to early 60s, creating a population of individuals of which little is known about how well they are protected against infectious disease. The goal of this work is to better understand if adults with Down syndrome are well protected against influenza following vaccination. We obtained plasma samples from 18 adults (average age = 31yo) with Down syndrome and 17 age/gender-matched disomic individuals, all vaccinated against influenza. Antibody concentration to influenza A was measured using ELISA and antibody titers were measured using a hemagglutinin inhibition assay. Statistical analysis was performed using Stata Statistical Software. Adults with Down syndrome had a significantly increased concentration of antibodies to a mixture of influenza A viral proteins; however, they had a significantly decreased titer to the Influenza A/Hong Kong compared to disomic controls. These findings suggest that more vigorous studies of B- and T-cell function in adults with Down syndrome with respect to influenza vaccination are warranted, and that this population may benefit from a high-dose influenza vaccine.

Beyond amyloid: Immune, cerebrovascular, and metabolic contributions to Alzheimer disease in people with Down syndrome

People with Down syndrome (DS) have increased risk of Alzheimer disease (AD), presumably conferred through genetic predispositions arising from trisomy 21. These predispositions necessarily include triplication of the amyloid precursor protein (APP), but also other Ch21 genes that confer risk directly or through interactions with genes on other chromosomes. We discuss evidence that multiple genes on chromosome 21 are associated with metabolic dysfunction in DS. The resulting dysregulated pathways involve the immune system, leading to chronic inflammation; the cerebrovascular system, leading to disruption of the blood brain barrier (BBB); and cellular energy metabolism, promoting increased oxidative stress. In combination, these disruptions may produce a precarious biological milieu that, in the presence of accumulating amyloid, drives the pathophysiological cascade of AD in people with DS. Critically, mechanistic drivers of this dysfunction may be targetable in future clinical trials of pharmaceutical and/or lifestyle interventions.

Down Syndrome: A Review of Key Perioperative Implications

Down syndrome (DS) is the most common chromosomal abnormality in humans that is compatible with life. This syndrome occurs when there is an extra copy of the 21st chromosome. Down syndrome is associated with numerous comorbidities that can pose challenges for the perioperative nurse caring for a patient with DS undergoing surgery. These challenges can affect the patient assessment, communication with the patient, and patient safety (eg, preventing complications). As the life expectancy of people with DS has increased, so too have the chances that perioperative nurses will care for a patient with this disorder. This article reviews the pathophysiology of DS, discusses common comorbidities that may directly affect perioperative care, and reviews an exemplar case study that demonstrates how personnel with knowledge of DS can positively influence surgical team decision making for these patients in the perioperative setting.

Clinical characteristics and comorbidities of COVID-19 in unvaccinated patients with Down syndrome: first year report in Brazil

Patients with Down syndrome (DS) are more affected by the Coronavirus Disease (COVID)-19 pandemic when compared with other populations. Therefore, the primary aim of our study was to report the death (case fatality rate) from SARS-CoV-2 infection in Brazilian hospitalized patients with DS from 03 January 2020 to 04 April 2021. The secondary objectives were (i) to compare the features of patients with DS and positive for COVID-19 (G1) to those with DS and with a severe acute respiratory infection (SARI) from other etiological factors (G2) to tease apart the unique influence of COVID-19, and (ii) to compare the features of patients with DS and positive for COVID-19 to those without DS, but positive for COVID-19 (G3) to tease apart the unique influence of DS. We obtained the markers for demographic profile, clinical symptoms, comorbidities, and the clinical features for SARI evolution during hospitalization in the first year of the COVID-19 pandemic in Brazil from a Brazilian open-access database. The data were compared between (i) G1 [1619 (0.4%) patients] and G2 [1431 (0.4%) patients]; and between (ii) G1 and G3 [222,181 (64.8%) patients]. The case fatality rate was higher in patients with DS and COVID-19 (G1: 39.2%), followed by individuals from G2 (18.1%) and G3 (14.0%). Patients from G1, when compared to G2, were older (≥ 25 years of age), presented more clinical symptoms related to severe illness and comorbidities, needed intensive care unit (ICU) treatment and non-invasive mechanical ventilation (MV) more frequently, and presented a nearly two fold-increased chance of death (OR = 2.92 [95% CI 2.44–3.50]). Patients from G1, when compared to G3, were younger (< 24 years of age), more prone to nosocomial infection, presented an increased chance for clinical symptoms related to a more severe illness; frequently needed ICU treatment, and invasive and non-invasive MV, and raised almost a three fold-increased chance of death (OR = 3.96 [95% CI 3.60–4.41]). The high case fatality rate in G1 was associated with older age (≥ 25 years of age), presence of clinical symptoms, and comorbidities, such as obesity, related to a more severe clinical condition. Unvaccinated patients with DS affected by COVID-19 had a high case fatality rate, and these patients had a different profile for comorbidities, clinical symptoms, and treatment (such as the need for ICU and MV) when compared with other study populations.

Upregulated Proteasome Subunits in COVID-19 Patients: A Link with Hypoxemia, Lymphopenia and Inflammation

Severe COVID-19 disease leads to hypoxemia, inflammation and lymphopenia. Viral infection induces cellular stress and causes the activation of the innate immune response. The ubiquitin-proteasome system (UPS) is highly implicated in viral immune response regulation. The main function of the proteasome is protein degradation in its active form, which recognises and binds to ubiquitylated proteins. Some proteasome subunits have been reported to be upregulated under hypoxic and hyperinflammatory conditions. Here, we conducted a prospective cohort study of COVID-19 patients (n = 44) and age-and sex-matched controls (n = 20). In this study, we suggested that hypoxia could induce the overexpression of certain genes encoding for subunits from the α and β core of the 20S proteasome and from regulatory particles (19S and 11S) in COVID-19 patients. Furthermore, the gene expression of proteasome subunits was associated with lymphocyte count reduction and positively correlated with inflammatory molecular and clinical markers. Given the importance of the proteasome in maintaining cellular homeostasis, including the regulation of the apoptotic and pyroptotic pathways, these results provide a potential link between COVID-19 complications and proteasome gene expression.

Specific Susceptibility to COVID-19 in Adults with Down Syndrome

The current SARS-CoV-2 outbreak, which causes COVID-19, is particularly devastating for individuals with chronic medical conditions, in particular those with Down Syndrome (DS) who often exhibit a higher prevalence of respiratory tract infections, immune dysregulation and potential complications. The incidence of Alzheimer's disease (AD) is much higher in DS than in the general population, possibly increasing further the risk of COVID-19 infection and its complications. Here we provide a biological overview with regard to specific susceptibility of individuals with DS to SARS-CoV-2 infection as well as data from a recent survey on the prevalence of COVID-19 among them. We see an urgent need to protect people with DS, especially those with AD, from COVID-19 and future pandemics and focus on developing protective measures, which also include interventions by health systems worldwide for reducing the negative social effects of long-term isolation and increased periods of hospitalization.

Multiple Organ Failure Associated with SARS-CoV-2 Infection in a Child with Down Syndrome: Is Trisomy 21 Associated with an Unfavourable Clinical Course?

Introduction

Down syndrome (DS) is one of the most frequent genomic disorders around the globe (∼1:700 births). During the COVID-19 pandemic, it has been recognized that children with DS are patients with a greater risk of presenting SARS-CoV-2 infection-related poor outcomes. Nonetheless, a few cases with DS and SARS-CoV-2 infection have been reported. Our aim is to describe the unfavorable clinical course of a child with DS infected with SARS-CoV-2 virus.

Case

Female, 2 years old, karyotype 47,XX,+21[30], previously diagnosed with a cyanotic congenital heart disease (tricuspid atresia and infundibular pulmonary stenosis, type Ib) who started with diarrhea, developed shortness of breath, and cyanosis and was admitted to the hospital presenting low-oxygen saturation (33%) requiring invasive mechanical ventilation support. The patient tested positive for SARS-CoV-2 infection. During hospitalization, the patient presented hypotension, anuria, retarded capillary filling, and metabolic acidosis; management with vasoactive drugs was needed. Nonetheless, the patient developed respiratory and cardiac failure, acute renal injury (AKIN-III), and septic shock. After 24 days of hospitalization, the patient died.

Conclusions

Multiple organ failure observed in the patient presented could be related to the triple gene dose of four interferon receptors (IFNAR1, IFNAR2, IFNGR2, and IL10RB) located at 21q22.11. Additionally, overexpression of TMPRSS2 at the pulmonary level, located also at 21q22.3, could be related with an increased susceptibility for the development of SARS-CoV-2 infection in DS patients.

Atypical Inflammatory Syndrome Triggered by SARS-CoV-2 in Infants with Down Syndrome

While adults with Down syndrome (DS) are at increased risk of severe COVID-19 pneumonia, little is known about COVID-19 in children with DS. In children without DS, SARS-CoV-2 can rarely cause severe COVID-19 pneumonia, or an even rarer and more typically pediatric condition, multisystem inflammatory syndrome in children (MIS-C). Although the underlying mechanisms are still unknown, MIS-C is thought to be primarily immune-mediated. Here, we describe an atypical, severe form of MIS-C in two infant girls with DS who were hospitalized for over 4 months. Immunological evaluation revealed pronounced neutrophilia, B cell depletion, increased circulating IL-6 and IL-8, and elevated markers of immune activation ICAM1 and FcɣRI. Importantly, uninfected children with DS presented with similar but less stark immune features at steady state, possibly explaining risk of further uncontrolled inflammation following SARS-CoV-2 infection. Overall, a severe, atypical form of MIS-C may occur in children with DS.

Comparison of COVID-19 and Non-COVID-19 Pneumonia in Down Syndrome

Whether the increased risk for coronavirus disease 2019 (COVID-19) hospitalization and death observed in Down syndrome (DS) are disease specific or also occur in individuals with DS and non-COVID-19 pneumonias is unknown. This retrospective cohort study compared COVID-19 cases in persons with DS hospitalized in Spain reported to the Trisomy 21 Research Society COVID-19 survey (n = 86) with admissions for non-COVID-19 pneumonias from a retrospective clinical database of the Spanish Ministry of Health (n = 2832 patients). In-hospital mortality rates were significantly higher for COVID-19 patients (26.7% vs. 9.4%), especially among individuals over 40 and patients with obesity, dementia, and/or epilepsy. The mean length of stay of deceased patients with COVID-19 was significantly shorter than in those with non-COVID-19 pneumonias. The rate of admission to an ICU in patients with DS and COVID-19 (4.3%) was significantly lower than that reported for the general population with COVID-19. Our findings confirm that acute SARS-CoV-2 infection leads to higher mortality than non-COVID-19 pneumonias in individuals with DS, especially among adults over 40 and those with specific comorbidities. However, differences in access to respiratory support might also account for some of the heightened mortality of individuals with DS with COVID-19.

COVID-19, Acute Lymphoblastic Leukemia, and Down Syndrome: A Short Review and a Case Report

SARS-CoV-2 which causes COVID-19 has been a great challenge to treat and deal with; despite strict measures that had been implemented by governments and organizations, worrying rates of morbidity and mortality are still being reported. Although available data have expressed that moderate or even mild forms of the disease are expected amongst most pediatrics cases, minimal data are available on the prognosis and the disease's complications on the immunocompromised, especially oncology patients. We report a case of relapsed precursor B-cell acute lymphoblastic leukemia of a child with Down syndrome and COVID-19 and outline the treatment regimen that we used.

Immune Dysregulation and the Increased Risk of Complications and Mortality Following Respiratory Tract Infections in Adults With Down Syndrome

The risk of severe outcomes following respiratory tract infections is significantly increased in individuals over 60 years, especially in those with chronic medical conditions, i.e., hypertension, diabetes, cardiovascular disease, dementia, chronic respiratory disease, and cancer. Down Syndrome (DS), the most prevalent intellectual disability, is caused by trisomy-21 in ~1:750 live births worldwide. Over the past few decades, a substantial body of evidence has accumulated, pointing at the occurrence of alterations, impairments, and subsequently dysfunction of the various components of the immune system in individuals with DS. This associates with increased vulnerability to respiratory tract infections in this population, such as the influenza virus, respiratory syncytial virus, SARS-CoV-2 (COVID-19), and bacterial pneumonias. To emphasize this link, here we comprehensively review the immunobiology of DS and its contribution to higher susceptibility to severe illness and mortality from respiratory tract infections.

Down syndrome and type I interferon: not so simple

Down syndrome (DS) is characterized by a collection of clinical features including intellectual disability, congenital malformations, and susceptibility to infections and autoimmune diseases. While the presence of an extra chromosome 21 is known to cause DS, the precise genetic annotation linked to specific clinical features is largely missing. However, there is growing evidence that two genes located on chromosome 21, IFNAR1 and IFNAR2, play an important role in disease pathogenesis. These genes encode the two subunits of the receptor for type I interferons (IFN-I), a group of potent antiviral and pro-inflammatory cytokines. Human monogenic diseases caused by uncontrolled IFN-I production and response have been well characterized, and they clinically overlap with DS but also have notable differences. Herein, we review the literature characterizing the role of IFN-I in DS and compare and contrast DS to other IFN-mediated conditions. The existing IFN-I literature serves as a rich resource for testable hypotheses to elucidate disease mechanisms in DS and is likely to open novel therapeutic avenues.

Are patients with Down syndrome vulnerable to life-threatening COVID-19?

Patients with Down syndrome are at increased risk of respiratory syncytial virus- and H1N1-related death. Literature on COVID-19 in Down syndrome patients is unavailable thus far. We describe the clinical course of 4 patients with Down syndrome during an outbreak of COVID-19. In all four patients, disease course was severe, warranting hospital care in three patients, with fatal outcome in one patient. Another patient receives supportive care in our institution. Our case series is the first report on probable increased risk of life-threatening disease course of COVID-19 in patients with Down syndrome. Proper surveillance, the adherence of social distancing, and the use of personal protective equipment will be essential in reducing morbidity and mortality in our patients.

Medical vulnerability of individuals with Down syndrome to severe COVID-19-data from the Trisomy 21 Research Society and the UK ISARIC4C survey

BACKGROUND

Health conditions, immune dysfunction, and premature aging associated with trisomy 21 (Down syndrome, DS) may impact the clinical course of COVID-19.

METHODS

The T21RS COVID-19 Initiative launched an international survey for clinicians or caregivers on patients with COVID-19 and DS. Data collected between April and October 2020 (N=1046) were analysed and compared with the UK ISARIC4C survey of hospitalized COVID-19 patients with and without DS.

FINDINGS

The mean age of COVID-19 patients with DS in the T21RS survey was 29 years (SD = 18). Similar to the general population, the most frequent signs and symptoms of COVID-19 were fever, cough, and shortness of breath. Joint/muscle pain and vomiting or nausea were less frequent (p < 0.01), whereas altered consciousness/confusion were more frequent (p < 0.01). Risk factors for hospitalization and mortality were similar to the general population with the addition of congenital heart defects as a risk factor for hospitalization. Mortality rates showed a rapid increase from age 40 and were higher in patients with DS (T21RS DS versus non-DS patients: risk ratio (RR) = 3.5 (95%-CI=2.6;4.4), ISARIC4C DS versus non-DS patients: RR = 2.9 (95%-CI=2.1;3.8)) even after adjusting for known risk factors for COVID-19 mortality.

INTERPRETATION

Leading signs/symptoms of COVID-19 and risk factors for severe disease course are similar to the general population. However, individuals with DS present significantly higher rates of medical complications and mortality, especially from age 40.

FUNDING

Down Syndrome Affiliates in Action, DSMIG-USA, GiGi's Playhouse, Jerome Lejeune Foundation, LuMind IDSC Foundation, The Matthew Foundation, NDSS, National Task Group on Intellectual Disabilities and Dementia Practices.

COVID-19 in patients with Down syndrome

PURPOSE

The aim of the current study was to determine whether COVID-19 is associated with a different presenting clinical picture or a more severe course of illness in people with Down syndrome (DS).

METHODS

All consecutive patients who were admitted at healthcare facilities anywhere in Fars province (located in the south of Iran with a population of 4,851,000 people) from 19 February 2020 to 20 November 2020 were included. For every patient with DS, three age- and sex-matched patients with COVID-19 and without any underlying medical conditions were selected as controls.

RESULTS

During the study period, 37,968 patients were hospitalized with a diagnosis of COVID-19. Eighteen patients had DS. Patients with DS were significantly more likely to be intubated [7 patients (39%)] compared with those without DS [3 patients (6%)]; p = 0.002. Patients with DS significantly more often died of COVID-19 compared with the controls [8 (44.4%) vs. 1 (1.9%); odds ratio: 24.37; 95% confidence interval 2.39-247.94; p = 0.007].

CONCLUSION

Patients with DS are among the high-risk populations with respect to severe COVID-19 and should receive the vaccine as soon as possible. Furthermore, they should receive more intensive care if they get hospitalized with the illness.

Network analysis of Down syndrome and SARS-CoV-2 identifies risk and protective factors for COVID-19

SARS-CoV-2 infection has spread uncontrollably worldwide while it remains unknown how vulnerable populations, such as Down syndrome (DS) individuals are affected by the COVID-19 pandemic. Individuals with DS have more risk of infections with respiratory complications and present signs of auto-inflammation. They also present with multiple comorbidities that are associated with poorer COVID-19 prognosis in the general population. All this might place DS individuals at higher risk of SARS-CoV-2 infection or poorer clinical outcomes. In order to get insight into the interplay between DS genes and SARS-cov2 infection and pathogenesis we identified the genes associated with the molecular pathways involved in COVID-19 and the host proteins interacting with viral proteins from SARS-CoV-2. We then analyzed the overlaps of these genes with HSA21 genes, HSA21 interactors and other genes consistently differentially expressed in DS (using public transcriptomic datasets) and created a DS-SARS-CoV-2 network. We detected COVID-19 protective and risk factors among HSA21 genes and interactors and/or DS deregulated genes that might affect the susceptibility of individuals with DS both at the infection stage and in the progression to acute respiratory distress syndrome. Our analysis suggests that at the infection stage DS individuals might be more susceptible to infection due to triplication of TMPRSS2, that primes the viral S protein for entry in the host cells. However, as the anti-viral interferon I signaling is also upregulated in DS, this might increase the initial anti-viral response, inhibiting viral genome release, viral replication and viral assembly. In the second pro-inflammatory immunopathogenic phase of the infection, the prognosis for DS patients might worsen due to upregulation of inflammatory genes that might favor the typical cytokine storm of COVID-19. We also detected strong downregulation of the NLRP3 gene, critical for maintenance of homeostasis against pathogenic infections, possibly leading to bacterial infection complications.

JAK1 Inhibition Blocks Lethal Immune Hypersensitivity in a Mouse Model of Down Syndrome

Individuals with Down syndrome (DS; trisomy 21) display hyperactivation of interferon (IFN) signaling and chronic inflammation, which could potentially be explained by the extra copy of four IFN receptor (IFNR) genes encoded on chromosome 21. However, the clinical effects of IFN hyperactivity in DS remain undefined. Here, we report that a commonly used mouse model of DS overexpresses IFNR genes and shows hypersensitivity to IFN ligands in diverse immune cell types. When treated repeatedly with a TLR3 agonist to induce chronic inflammation, these animals overexpress key IFN-stimulated genes, induce cytokine production, exhibit liver pathology, and undergo rapid weight loss. Importantly, the lethal immune hypersensitivity and cytokine production and the ensuing pathology are ameliorated by JAK1 inhibition. These results indicate that individuals with DS may experience harmful hyperinflammation upon IFN-inducing immune stimuli, as observed during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, pointing to JAK1 inhibition as a strategy to restore immune homeostasis in DS.

Trisomy 21 as a Risk Factor for Severe Illness in COVID-19: Report of two Cases

COVID-19 leads to mild symptoms within the majority of infected patients, but can cause severe multiple organ failure and death. There is only limited information regarding the consequences of this new emerging infection with congenital disorders. According to the previous studies, many people with Down syndrome are considered high risk for complications related to respiratory diseases. We report two trisomy 21 patients who suffered from COVID-19 and summarize the early experience with COVID-19 and Down syndrome. The course of the disease was severe in these two cases, and our concern is close monitoring of the patients with Down syndrome for early signs of COVID-19.

Down Syndrome patients with COVID-19 pneumonia: A high-risk category for unfavourable outcome

We report two cases of Corona Virus Disease-19 (COVID-19) in patients with Down Syndrome (DS) and describe the identification, diagnosis, clinical course and management of the infection. Down Syndrome, which is caused by trisomy 21, is characterized by immune dysregulation, anatomical differences in the upper respiratory tract and higher rate of comorbidities. All these risk factors can contribute to more severe clinical presentations of COVID-19 in this population. It is essential to raise awareness of the clinical relevance of SARS-COV-2 infection in DS patients, as well as in other most vulnerable patients, in order to improve their management and treatment and to encourage vaccinating these individuals early, once a vaccination is available.

Down's syndrome and COVID-19: risk or protection factor against infection? A molecular and genetic approach

Down syndrome (DS) is the most common genetic cause of learning difficulties and intellectual disabilities. DS patients often present with several congenital defects and chronic diseases, including immunity disorders. Elevated levels of pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) have been seen, which appear to vary with age. At birth, patients present with combined immunodeficiency, with frequent infections that decrease with age. Furthermore, high levels of IL-4 and IL-10 with anti-inflammatory properties and low levels of IL-6 and TNF-α are described in children. The immune system is believed to play an essential role in SARS-CoV-2 pathogenesis, and it has been associated with elevated levels of pro-inflammatory cytokines and an exaggerated cytokine release syndrome (CRS) that may eventually trigger a severe situation called cytokine storm. On the other hand, genetic features seem to be involved in the predisposition to illness and its severity. Overexpression of DSCR1 and ZAKI-4 inhibits the translocation of activated T lymphocyte nuclear factor (NF-AT) to the nucleus, a main step in the inflammatory responsiveness. We discuss here the possible role of immunology and genetic features of DS in the infection and prognosis in COVID-19.

An international survey on the impact of COVID-19 in individuals with Down syndrome

BACKGROUND

Health conditions and immune dysfunction associated with trisomy 21 (Down syndrome, DS) may impact the clinical course of COVID-19 once infected by SARS-CoV-2.

METHODS

The T21RS COVID-19 Initiative launched an international survey for clinicians or caregivers/family members on patients with COVID-19 and DS (N=1046). De-identified survey data collected between April and October 2020 were analysed and compared with the UK ISARIC4C survey of hospitalized COVID-19 patients with and without DS. COVID-19 patients with DS from the ISARIC4C survey (ISARIC4C DS cases=100) were matched to a random set of patients without DS (ISARIC4C controls=400) and hospitalized DS cases in the T21RS survey (T21RS DS cases=100) based on age, gender, and ethnicity.

FINDING

The mean age in the T21RS survey was 29 years (SD=18), 73% lived with their family. Similar to the general population, the most frequent signs and symptoms of COVID-19 were fever, cough, and shortness of breath. Pain and nausea were reported less frequently (p<0.01), whereas altered consciousness/confusion were reported more frequently (p<0.01). Risk factors for hospitalization and mortality were similar to the general population (age, male gender, diabetes, obesity, dementia) with the addition of congenital heart defects as a risk factor for hospitalization. Mortality rates showed a rapid increase from age 40 and were higher than for controls (T21RS DS versus controls: risk ratio (RR)=3.5 (95%-CI=2.6;4.4), ISARIC4C DS versus controls: RR=2.9 (95%-CI=2.1;3.8)) even after adjusting for known risk factors for COVID-19 mortality.

INTERPRETATION

Leading signs/symptoms of COVID-19 and risk factors for severe disease course are similar to the general population. However, individuals with DS present significantly higher rates of mortality, especially from age 40.

FUNDING

Down Syndrome Affiliates in Action, Down Syndrome Medical Interest Group-USA, GiGi's Playhouse, Jerome Lejeune Foundation, LuMind IDSC Foundation, Matthews Foundation, National Down Syndrome Society, National Task Group on Intellectual Disabilities and Dementia Practices.

Pneumonia and respiratory infections in Down syndrome: A scoping review of the literature

Pneumonia and respiratory infections impact infants and children with Down syndrome; pneumonia is a leading cause of mortality in adults with Down syndrome. We aimed to review the literature to evaluate gaps and address key questions. A series of key questions were formulated a priori to inform the search strategy and review process; addressed prevalence, severity, etiology, risk factors, preventive methods, screening, and financial costs, potential benefits or harms of screening. Using the National Library of Medicine database, PubMed, detailed literature searches on pneumonia and respiratory infections in Down syndrome were performed. Previously identified review articles were also assessed. The quality of available evidence was then evaluated and knowledge gaps were identified. Forty-two relevant original articles were identified which addressed at least one key question. Study details including research design, internal validity, external validity, and relevant results are presented. Pneumonia and respiratory infections are more prevalent and more severe in individuals with Down syndrome compared to healthy controls through literature review, yet there are gaps in the literature regarding the etiology of pneumonia, the infectious organism, risk factors for infection, and to guide options for prevention and screening. There is urgent need for additional research studies in Down syndrome, especially in the time of the current COVID-19 pandemic.

Individuals with Down syndrome hospitalized with COVID-19 have more severe disease

PURPOSE

Rare genetic conditions like Down syndrome (DS) are historically understudied. Infection is a leading cause of mortality in DS, along with cardiac anomalies. Currently, it is unknown how the COVID-19 pandemic affects individuals with DS. Herein, we report an analysis of individuals with DS who were hospitalized with COVID-19 in New York, New York, USA.

METHODS

In this retrospective, dual-center study of 7246 patients hospitalized with COVID-19, we analyzed all patients with DS admitted in the Mount Sinai Health System and Columbia University Irving Medical Center. We assessed hospitalization rates, clinical characteristics, and outcomes.

RESULTS

We identified 12 patients with DS. Hospitalized individuals with DS are on average ten years younger than patients without DS. Patients with DS have more severe disease than controls, particularly an increased incidence of sepsis and mechanical ventilation.

CONCLUSION

We demonstrate that individuals with DS who are hospitalized with COVID-19 are younger than their non-DS counterparts, and that they have more severe disease than age-matched controls. We conclude that particular care should be considered for both the prevention and treatment of COVID-19 in these patients.

Impact of Coronavirus Disease 2019 (COVID-19) on Patients With Congenital Heart Disease Across the Lifespan: The Experience of an Academic Congenital Heart Disease Center in New York City

Background We sought to assess the impact and predictors of coronavirus disease 2019 (COVID-19) infection and severity in a cohort of patients with congenital heart disease (CHD) at a large CHD center in New York City. Methods and Results We performed a retrospective review of all individuals with CHD followed at Columbia University Irving Medical Center who were diagnosed with COVID-19 between March 1, 2020 and July 1, 2020. The primary end point was moderate/severe response to COVID-19 infection defined as (1) death during COVID-19 infection; or (2) need for hospitalization and/or respiratory support secondary to COVID-19 infection. Among 53 COVID-19-positive patients with CHD, 10 (19%) were <18 years of age (median age 34 years of age). Thirty-one (58%) had complex congenital anatomy including 10 (19%) with a Fontan repair. Eight (15%) had a genetic syndrome, 6 (11%) had pulmonary hypertension, and 9 (17%) were obese. Among adults, 18 (41%) were physiologic class C or D. For the entire cohort, 9 (17%) had a moderate/severe infection, including 3 deaths (6%). After correcting for multiple comparisons, the presence of a genetic syndrome (odds ratio [OR], 35.82; P=0.0002), and in adults, physiological Stage C or D (OR, 19.38; P=0.002) were significantly associated with moderate/severe infection. Conclusions At our CHD center, the number of symptomatic patients with COVID-19 was relatively low. Patients with CHD with a genetic syndrome and adults at advanced physiological stage were at highest risk for moderate/severe infection.

Down Syndrome and COVID-19: A Perfect Storm?

People with Down syndrome show signs of chronic immune dysregulation, including a higher prevalence of autoimmune disorders, increased rates of hospitalization during respiratory viral infections, and higher mortality rates from pneumonia and sepsis. At the molecular and cellular levels, they show markers of chronic autoinflammation, including interferon hyperactivity, elevated levels of many inflammatory cytokines and chemokines, and changes in diverse immune cell types reminiscent of inflammatory conditions observed in the general population. However, the impact of this immune dysregulation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and CoV disease of 2019 (COVID-19) remains unknown. This Perspective outlines why individuals with Down syndrome should be considered an at-risk population for severe COVID-19. Specifically, the immune dysregulation caused by trisomy 21 may result in an exacerbated cytokine release syndrome relative to that observed in the euploid population, thus justifying additional monitoring and specialized care for this vulnerable population.

Inflammation as a Modulator of Host Susceptibility to Pulmonary Influenza, Pneumococcal, and Co-Infections

Bacterial and viral pathogens are predominant causes of pulmonary infections and complications. Morbidity and mortality from these infections is increased in populations that include the elderly, infants, and individuals with genetic disorders such as Down syndrome. Immune senescence, concurrent infections, and other immune alterations occur in these susceptible populations, but the underlying mechanisms that dictate increased susceptibility to lung infections are not fully defined. Here, we review unique features of the lung as a mucosal epithelial tissue and aspects of inflammatory and immune responses in model pulmonary infections and co-infections by influenza virus and Streptococcus pneumoniae. In these models, lung inflammatory responses are a double-edged sword: recruitment of immune effectors is essential to eliminate bacteria and virus-infected cells, but inflammatory cytokines drive changes in the lung conducive to increased pathogen replication. Excessive accumulation of inflammatory cells also hinders lung function, possibly causing death of the host. Some animal studies have found that targeting host modulators of lung inflammatory responses has therapeutic or prophylactic effects in these infection and co-infection models. However, conflicting results from other studies suggest microbiota, sequence of colonization, or other unappreciated aspects of lung biology also play important roles in the outcome of infections. Regardless, a predisposition to excessive or aberrant inflammatory responses occurs in susceptible human populations. Hence, in appropriate contexts, modulation of inflammatory responses may prove effective for reducing the frequency or severity of pulmonary infections. However, there remain limitations in our understanding of how this might best be achieved—particularly in diverse human populations.

Clinical implications of immune-mediated diseases in children with Down syndrome

Children with Down syndrome have changes in their innate and adaptive immunity, which contribute to increased rates of infections, autoimmune diseases, and haematological malignancies. While improved care for congenital heart disease has decreased mortality and morbidity, complications related to immune-mediated diseases continue to limit the life expectancy in Down syndrome. Infectious diseases are common and have a significant effect on development, behaviour and quality of life. Infection frequency and severity are influenced by various anatomical and physiological alterations in addition to immunological changes in Down syndrome. Thus, prevention of respiratory tract infections requires a multifactorial approach. This could include additional active and/or passive immunizations, prophylactic antibiotics, immunoglobulin replacement and ear, nose and throat surgical interventions. Autoimmune conditions like coeliac disease, type I diabetes mellitus and thyroid disease are classically mentioned in the context of Down syndrome. However, autoinflammatory conditions are more prevalent as well. Screening for autoimmune diseases is required and immunosuppression has to be used with caution. Future studies should address optimal screening programmes for immune-mediated diseases in individuals with Down syndrome, as well as the effect of immune modulation, to further decrease morbidity and mortality, and improve the quality of life of individuals with Down syndrome.

Vaccination in people with disability: a review

People with disabilities are vulnerable to complications from vaccine-preventable diseases, and every effort should be made to ensure equitable access to immunization for this population. This paper aims to summarize the research on immunizations in people with disabilities, in order to ensure a comprehensive understanding of knowledge in this area and direct further research. The literature is weighted towards coverage data that is difficult to synthesize because of the different definitions of disability, and the variety of settings, vaccinations and age groups across the studies. In-depth qualitative data and data from a variety of health-care providers and people with disability is notably lacking. This is vital to redress in order to develop effective immunization interventions in this population.

Palivizumab use in infants with Down syndrome-report from the German Synagis™ Registry 2009-2016

Infants with Down syndrome (DS) face an increased risk of respiratory tract infections. Recent studies describe DS as independent risk factor for a complicated clinical course in infants with respiratory syncytial virus (RSV) infection. The prospective observational German Synagis™ Registry comprises data from 249 children below 25 months of age with DS and palivizumab prophylaxis 2009-2016 (1191 administrations; mean 4.8 per patient and season). The median gestational age and the birth weight in patients without and with DS were 31 versus 37 weeks (P < 0.001) and 1590 versus 2750 g, respectively (P < 0.001). Patients with DS significantly more often had congenital heart disease (CHD), siblings in kindergarten or school, treatment with oxygen at home, immunodeficiency, and neuromuscular impairment. The RSV-related hospitalization rate in patients with DS was 1.20%; the hospitalization rate in patients without DS was 0.71%.

CONCLUSION

Data from 249 children with DS receiving palivizumab prophylaxis in seven consecutive RSV seasons (2009-2016) in Germany reveal important differences between patients with and without DS concerning the main indication for palivizumab use and additional risk factors. Bearing in mind the limitations of an uncontrolled postmarketing observational study, the results confirm the field effectiveness of palivizumab prophylaxis in this special population. What is Known: • Recent studies describe the Down syndrome as independent risk factor for a complicated clinical course in infants with RSV infection. What is New: • Compared with other infants receiving palivizumab prophylaxis, patients with Down syndrome significantly more often had congenital heart disease, siblings in kindergarten or school, treatment with oxygen at home, immunodeficiency, and neuromuscular impairment. • In infants with palivizumab prophylaxis breakthrough, RSV-related hospitalization rates were not significantly higher in those with Down syndrome.

Low titers of serum antibodies inhibiting hemagglutination predict fatal fulminant influenza A(H1N1) 2009 infection

RATIONALE

The biology of fatal pandemic influenza infection remains undefined.

OBJECTIVES

To characterize the virologic and immune parameters associated with severity or death in patients who required mechanical ventilation for A(H1N1) 2009 pneumonia of various degrees of severity during the two waves of the 2009-2011 pandemic in Paris, France.

METHODS

This multicenter study included 34 unvaccinated patients with very severe or fatal confirmed influenza A(H1N1) infections. It analyzed plasma A(H1N1) 2009 reverse-transcriptase polymerase chain reaction, hemagglutinin 222G viral mutation, and humoral and cellular immune responses to the virus, assessed in hemagglutination inhibition (HI), microneutralization, ELISA, lymphoproliferative, ELISpot IFN-γ, and cytokine and chemokine assays.

MEASUREMENTS AND MAIN RESULTS

The patients' median age was 35 years. Influenza A(H1N1) 2009 viremia was detected in 4 of 34 cases, and a 222G hemagglutinin mutation in 7 of 17 cases, all of them with sequential organ failure assessment greater than or equal to 8. HI antibodies were detectable in 19 of 26 survivors and undetectable in all six fatal fulminant cases. ELISA and microneutralization titers were concordant. B-cell immunophenotyping and plasma levels of immunoglobulin classes did not differ between patients who survived and died. After immune complex dissociation, influenza ELISA serology became strongly positive in the bronchoalveolar lavage of the two fatal cases tested. H1N1-specific T-cell responses in lymphoproliferative and IFN-γ assays were detectable in survivors' peripheral blood, and lymphoproliferative assays were negative in the three fatal cases tested. Plasma levels of IL-6 and IL-10 were high in fatal cases and correlated with severity. Finally, a negative HI serology 4 days after the onset of influenza symptoms predicted death from fulminant influenza (P = 0.04).

CONCLUSIONS

Early negative A(H1N1) 2009 HI serology can predict death from influenza. This negative serology in fatal cases in young adults reflects the trapping of anti-H1N1 antibodies in immune complexes in the lungs, associated with poor specific helper T-cell response. Clinical trial registered with www.clinicaltrials.gov (NCT 01089400).

Pathogenic potential of interferon αβ in acute influenza infection

Influenza symptoms vary from mild disease to death; however, determinants of severity are unclear. Type I interferons (IFNαβ) are recognized as key antiviral cytokines. Here we show that, surprisingly, influenza-infected 129 mice have increased lung damage, morbidity and mortality, yet higher levels of IFNαβ, than C57BL/6 mice. Consistently, IFNα treatment of influenza-infected C57BL/6 mice increases morbidity. IFNαβ receptor deficiency in 129 mice decreases morbidity, lung damage, proinflammatory cytokines and lung-infiltrating inflammatory cells, and reduces expression of the death-inducing receptor DR5 on lung epithelia and its ligand TRAIL on inflammatory monocytes. Depletion of PDCA-1+ cells or interruption of TRAIL-DR5 interaction protects infected 129 mice. Selective lack of IFNαβ signalling in stromal cells abolishes epithelial DR5 upregulation and apoptosis, reducing host susceptibility. Hence, excessive IFNαβ signalling in response to acute influenza infection can result in uncontrolled inflammation and TRAIL-DR5-mediated epithelial cell death, which may explain morbidity and has important implications for treatment of severe disease.

Increased production of interleukin-10 in children with Down syndrome upon ex vivo stimulation with Streptococcus pneumoniae

BACKGROUND

Children with Down syndrome (DS) have an increased susceptibility to infections, due to altered humoral and/or cellular immunity. The aim of the study was to determine the cytokine production in whole blood of children with DS upon stimulation with heat-killed Streptococcus pneumoniae and lipopolysaccharide (LPS), in comparison with their healthy siblings.

METHODS

Whole blood of 61 children with DS and 57 of their healthy siblings was stimulated with 200 ng/ml LPS and 4 × 10(7) colony-forming units/ml S. pneumoniae during 6, 24, and 48 h. Concentrations of pro- and anti-inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-12p70, and IL-10 were determined at all time points.

RESULTS

Children with DS show an increased IL-10 production upon stimulation with S. pneumoniae compared to their healthy siblings. At most time points, no significant differences were seen in cytokine production upon stimulation with LPS.

CONCLUSION

Children with DS may be prone to a severe course of pneumococcal pneumonia, because of an increased anti-inflammatory response.

The effect of physician's recommendation on seasonal influenza immunization in children with chronic diseases

BACKGROUND

Despite recommendations by Health Authorities, influenza immunization coverage remains low in children with chronic diseases. Different medical providers involved in the management of children with chronic conditions may affect the pattern of influenza vaccine recommendations and coverage. The likelihood of vaccination by type of provider in children with chronic conditions is poorly understood. Therefore, the objectives of this study were to analyze the pattern and the effect of recommendations for seasonal influenza immunization provided by different physician profiles to families of children with chronic diseases and to measure the frequency of immunization in the study population.

METHODS

We recruited children with chronic diseases aged 6 months-18 years who subsequently presented to specialty clinics for routine follow-up visits, during spring 2009, in three Italian Regions Families of children with chronic diseases were interviewed during routine visits at reference centers through a face-to-face interview. We analyzed the following immunization predictors: having received a recommendation toward influenza immunization by a health provider; child's sex and age; mothers and fathers' age; parental education and employment; underlying child's disease; number of contacts with health providers in the previous year. Influenza immunization coverage was calculated as the proportion of children who received at least one dose of seasonal influenza vaccine in the previous season. We calculated prevalence ratios and we used a generalized linear model with Poisson family, log link and robust error variance to assess the effect of socio-demographic variables, underlying diseases, and recommendations provided by physicians on influenza immunization.

RESULTS

We enrolled 275 families of children with chronic diseases. Overall influenza coverage was 57.5%, with a low of 25% in children with neurological diseases and a high of 91.2% in those with cystic fibrosis. While 10.6% of children who did not receive any recommendation toward influenza immunization were immunized, among those who received a recommendation 87.5-94.7% did, depending on the health professional providing the recommendation. Receiving a recommendation by any provider is a strong predictor of immunization (PR = 8.5 95% CI 4.6;15.6) Most children received an immunization recommendation by a specialty (25.8%) or a family pediatrician (23.3%) and were immunized by a family pediatrician (58.7%) or a community vaccinator (55.2%).

CONCLUSIONS

Receiving a specific recommendation by a physician is a strong determinant of being immunized against seasonal influenza in children with chronic diseases independently of other factors. Heterogeneity exists among children with different chronic diseases regarding influenza recommendation despite international guidelines. Increasing the frequency of appropriate recommendations toward influenza immunization by physicians is a single powerful intervention that may increase coverage in children with chronic conditions.

Frequency of lower respiratory tract infections in relation to adaptive immunity in children with Down syndrome compared to their healthy siblings

AIM

Children with Down syndrome (DS) experience respiratory tract infections (RTIs) more frequently than healthy children. We investigated whether this is related to different immunological characteristics associated with DS.

METHODS

The study group consisted of 22 children with DS and 22 of their healthy, age-range matched siblings. Data were collected on infections and hospitalizations because of lower RTIs. Immunoglobulin and IgG subclass levels in blood, as well as lymphocyte and T cell (subset) counts, were determined.

RESULTS

The children with DS had a significantly higher frequency of lower RTIs and related hospitalization than their siblings. We also found significantly reduced IgG2 levels as well as significantly lower counts of total lymphocytes, CD4(+) T lymphocytes, CD4(+) invariant natural killer (iNKT) cells and regulatory T cells in the DS group.

CONCLUSION

In children with DS, reduced levels of IgG2, total lymphocytes, T lymphocytes, iNKT cells and regulatory T cells might contribute to their higher susceptibility to lower RTIs.

Increased pro-inflammatory cytokine production in Down Syndrome children upon stimulation with live influenza A virus

PURPOSE

Children with down syndrome (DS) have an increased susceptibility to infections, due to altered humoral and/or cellular immunity. The aim of this study was to determine the cytokine production in whole blood of children with DS upon stimulation with live influenza A virus.

METHODS

Whole blood of 61 children with DS and 57 of their healthy siblings was stimulated with 2.5 × 10(4) TCID50/ml influenza A virus during 6, 24, and 48 h. TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-12p70, IFN-α, IFN-γ concentrations, and viral load were measured at all time points.

RESULTS

At most of the time points, TNF-α, IL-1β, IL-6, and IL-8 concentrations were significantly higher in children with DS following stimulation with live influenza A virus. IFN-α and IFN-γ levels were also significantly higher in the DS group. Viral clearance, however, was equal in both groups.

CONCLUSIONS

Children with DS have an altered immune response to influenza A virus. The production of higher levels of pro-inflammatory cytokines may be responsible for a more severe clinical course of viral disease in these children.

Case-based reported mortality associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection in the Netherlands: the 2009-2010 pandemic season versus the 2010-2011 influenza season

BACKGROUND

In contrast to seasonal influenza epidemics, where the majority of deaths occur amongst elderly, a considerable part of the 2009 pandemic influenza related deaths concerned relatively young people. In the Netherlands, all deaths associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection had to be notified, both during the 2009-2010 pandemic season and the 2010-2011 influenza season. To assess whether and to what extent pandemic mortality patterns were reverting back to seasonal patterns, a retrospective analyses of all notified fatal cases associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection was performed.

METHODS

The notification database, including detailed information about the clinical characteristics of all notified deaths, was used to perform a comprehensive analysis of all deceased patients with a laboratory-confirmed influenza A(H1N1) 2009 virus infection. Characteristics of the fatalities with respect to age and underlying medical conditions were analysed, comparing the 2009-2010 pandemic and the 2010-2011 influenza season.

RESULTS

A total of 65 fatalities with a laboratory-confirmed influenza A(H1N1) 2009 virus infection were notified in 2009-2010 and 38 in 2010-2011. During the pandemic season, the population mortality rates peaked in persons aged 0-15 and 55-64 years. In the 2010-2011 influenza season, peaks in mortality were seen in persons aged 0-15 and 75-84 years. During the 2010-2011 influenza season, the height of first peak was lower compared to that during the pandemic season. Underlying immunological disorders were more common in the pandemic season compared to the 2010-2011 season (p = 0.02), and cardiovascular disorders were more common in the 2010-2011 season (p = 0.005).

CONCLUSIONS

The mortality pattern in the 2010-2011 influenza season still resembled the 2009-2010 pandemic season with a peak in relatively young age groups, but concurrently a clear shift toward seasonal patterns was seen, with a peak in mortality in the elderly, i.e. ≥ 75 years of age.

Decreased AIRE expression and global thymic hypofunction in Down syndrome

The Down syndrome (DS) immune phenotype is characterized by thymus hypotrophy, higher propensity to organ-specific autoimmune disorders, and higher susceptibility to infections, among other features. Considering that AIRE (autoimmune regulator) is located on 21q22.3, we analyzed protein and gene expression in surgically removed thymuses from 14 DS patients with congenital heart defects, who were compared with 42 age-matched controls with heart anomaly as an isolated malformation. Immunohistochemistry revealed 70.48 ± 49.59 AIRE-positive cells/mm(2) in DS versus 154.70 ± 61.16 AIRE-positive cells/mm(2) in controls (p < 0.0001), and quantitative PCR as well as DNA microarray data confirmed those results. The number of FOXP3-positive cells/mm(2) was equivalent in both groups. Thymus transcriptome analysis showed 407 genes significantly hypoexpressed in DS, most of which were related, according to network transcriptional analysis (FunNet), to cell division and to immunity. Immune response-related genes included those involved in 1) Ag processing and presentation (HLA-DQB1, HLA-DRB3, CD1A, CD1B, CD1C, ERAP) and 2) thymic T cell differentiation (IL2RG, RAG2, CD3D, CD3E, PRDX2, CDK6) and selection (SH2D1A, CD74). It is noteworthy that relevant AIRE-partner genes, such as TOP2A, LAMNB1, and NUP93, were found hypoexpressed in DNA microarrays and quantitative real-time PCR analyses. These findings on global thymic hypofunction in DS revealed molecular mechanisms underlying DS immune phenotype and strongly suggest that DS immune abnormalities are present since early development, rather than being a consequence of precocious aging, as widely hypothesized. Thus, DS should be considered as a non-monogenic primary immunodeficiency.