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Background: Hydroxychloroquine has not been associated with improved survival among hospitalized COVID-19 patients in the majority of observational studies and similarly was not identified as an effective prophylaxis following exposure in a prospective randomized trial. We aimed to explore the role of hydroxychloroquine therapy in mildly symptomatic patients diagnosed in the outpatient setting., Methods: We examined the association between outpatient hydroxychloroquine exposure and the subsequent progression of disease among mildly symptomatic non-hospitalized patients with documented SARS-CoV-2 infection. The primary outcome assessed was requirement of hospitalization. Data was obtained from a retrospective review of electronic health records within a New Jersey USA multi-hospital network. We compared outcomes in patients who received hydroxychloroquine with those who did not applying a multivariable logistic model with propensity matching., Results: Among 1274 outpatients with documented SARS-CoV-2 infection 7.6% were prescribed hydroxychloroquine. In a 1067 patient propensity matched cohort, 21.6% with outpatient exposure to hydroxychloroquine were hospitalized, and 31.4% without exposure were hospitalized. In the primary multivariable logistic regression analysis with propensity matching there was an association between exposure to hydroxychloroquine and a decreased rate of hospitalization from COVID-19 (OR 0.53; 95% CI, 0.29, 0.95). Sensitivity analyses revealed similar associations. QTc prolongation events occurred in 2% of patients prescribed hydroxychloroquine with no reported arrhythmia events among those with data available., Conclusions: In this retrospective observational study of SARS-CoV-2 infected non-hospitalized patients hydroxychloroquine exposure was associated with a decreased rate of subsequent hospitalization. Additional exploration of hydroxychloroquine in this mildly symptomatic outpatient population is warranted.

Histoplasmosis, caused by the dimorphic environmental fungus Histoplasma capsulatum, is a major mycosis on the global stage. Acquisition of the fungus by mammalian hosts can be clinically silent or it can lead to life-threatening systemic disease, which can occur in immunologically intact or deficient hosts, albeit severe disease is more likely in the setting of compromised cellular immunity. H. capsulatum yeast cells are highly adapted to the mammalian host as they can effectively survive within intracellular niches in select phagocytic cells. Understanding the biological response by both the host and H. capsulatum will facilitate improved approaches to prevent and/or modify disease. This review presents our current understanding of the major pathogenic mechanisms involved in histoplasmosis.

Epidemiologic studies have reported an inverse relationship between childhood Helicobacter pylori infection and development of allergic asthma. Because lung epithelium plays an important role in allergic asthma pathogenesis, we hypothesized that H. pylori may directly influence airway epithelial cell innate immune function, particularly in early childhood. To test our hypothesis, we established an in vitro H. pylori infection model using primary tracheobronchial epithelial cell cultures derived from infant, juvenile and adult rhesus monkeys. Airway epithelial cell cultures were infected with wild-type or cag pathogenicity island mutant H. pylori strains, followed by evaluation of IL-8 and IL-6 protein synthesis. We found that H. pylori primarily increased IL-8 synthesis in a MOI and age-dependent fashion, with a greater than 4-fold induction in infant versus adult cultures. H. pylori-induced IL-8 synthesis in infant and juvenile cultures was significantly reduced by cag pathogenicity island mutants, indicating a requirement for the type IV secretion system. Although peptidoglycan recognition of nucleotide binding oligomerization domain-containing protein 1 (NOD1) and NF-kappaB have been implicated as key cytokine signaling molecules for H. pylori infection in gastric epithelium, NOD1 (ML130) or NF-kappaB (JSH-23) inhibitors minimally affected IL-8 synthesis in airway epithelial cell cultures following H. pylori infection. In contrast, inhibition of the p38 MAP kinase pathway (SB203580) resulted in almost complete suppression of H. pylori-induced IL-8 synthesis. Collectively, these results indicate that H. pylori can preferentially elicit IL-8 synthesis in a model of pediatric airway epithelium using the type IV secretion system via p38 MAP kinase.

Most infant deaths occur in the first year of life. Yet, our knowledge of immune development during this period is scarce and derived from cord blood (CB) only. To more effectively combat pediatric diseases, a deeper understanding of the kinetics and the factors that regulate the maturation of immune functions in early life is needed. Increased disease susceptibility of infants is generally attributed to T helper 2-biased immune responses. The differentiation of CD4 + T cells along a specific T helper cell lineage is dependent on the pathogen type, and on costimulatory and cytokine signals provided by antigen-presenting cells. Cytokines also regulate many other aspects of the host immune response. Therefore, toward the goal of increasing our knowledge of early immune development, we defined the temporal development of the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling function of CD4 + T cells using cross-sectional blood samples from healthy infants ages 0 (birth) to 14 months. We specifically focused on cytokines important in T cell differentiation (IFN-γ, IL-12, and IL-4) or in T cell survival and expansion (IL-2 and IL-7) in infant CD4 + T cells. Independent of the cytokine tested, JAK/STAT signaling in infant compared to adult CD4 + T cells was impaired at birth, but increased during the first year, with the most pronounced changes occurring in the first 6 months. The relative change in JAK/STAT signaling of infant CD4 + T cells with age was distinct for each cytokine tested. Thus, while about 60% of CB CD4 + T cells could efficiently activate STAT6 in response to IL-4, less than 5% of CB CD4 + T cells were able to activate the JAK/STAT pathway in response to IFN-γ, IL-12 or IL-2. By 4-6 months of age, the activation of the cytokine-specific STAT molecules was comparable to adults in response to IL-4 and IFN-γ, while IL-2- and IL-12-induced STAT activation remained below adult levels even at 1 year. These results suggest that common developmental and cytokine-specific factors regulate the maturation of the JAK/STAT signaling function in CD4 + T cells during the first year of life.

Our goal is to develop a pediatric combination vaccine to protect the vulnerable infant population against human immunodeficiency virus type 1 (HIV-1) and tuberculosis (TB) infections. The vaccine consists of an auxotroph Mycobacterium tuberculosis strain that coexpresses HIV antigens. Utilizing an infant rhesus macaque model, we have previously shown that this attenuated M. tuberculosis (AMtb)-simian immunodeficiency virus (SIV) vaccine is immunogenic, and although the vaccine did not prevent oral SIV infection, a subset of vaccinated animals was able to partially control virus replication. However, unexpectedly, vaccinated infants required fewer SIV exposures to become infected compared to naive controls. Considering that the current TB vaccine, Mycobacterium bovis bacillus Calmette-Guérin (BCG), can induce potent innate immune responses and confer pathogen-unspecific trained immunity, we hypothesized that an imbalance between enhanced myeloid cell function and immune activation might have influenced the outcome of oral SIV challenge in AMtb-SIV-vaccinated infants. To address this question, we used archived samples from unchallenged animals from our previous AMtb-SIV vaccine studies and vaccinated additional infant macaques with BCG or AMtb only. Our results show that vaccinated infants, regardless of vaccine strain or regimen, had enhanced myeloid cell responses. However, CD4 + T cells were concurrently activated, and the persistence of these activated target cells in oral and/or gastrointestinal tissues may have facilitated oral SIV infection. Immune activation was more pronounced in BCG-vaccinated infant macaques than in AMtb-vaccinated infant macaques, indicating a role for vaccine attenuation. These findings underline the importance of understanding the interplay of vaccine-induced immunity and immune activation and its effect on HIV acquisition risk and outcome in infants., (Copyright © 2017 American Society for Microbiology.)

Introduction: Pediatric emergency physicians (PEPs) are well established as primary emergency department (ED) providers in dedicated pediatric centers and university settings. However, the optimum role of these subspecialists is less well defined in the community hospital environment. This study examined the impact on the ED care of children after the introduction of 10 PEPs into a simulated medical community., Methods: A computer-generated community was created, containing 10 community hospitals treating 250,000 pediatric ED patients. Children requiring ED treatment received their care at the closest ED to their location. Ten PEPs were introduced into the community, and their impact on patient care was examined under 2 different models. In a restrictive model, the PEPs established 2 full-time pediatric EDs within the 2 busiest hospitals, whereas, in a distributive model, the PEPs were distributed throughout the 8 busiest hospitals. In the 8-hospital model, the PEPs provided direct patient care along with the general emergency physicians in that facility and also provided educational, administrative, and performance improvement support for the department. In the restrictive model, the PEPs impacted the care of 100% of the children presenting for treatment at their 2 practice sites. In the distributive model, impact included the direct patient care by the PEP but also included changes produced in the care provided by the general emergency physicians at the site. Three different levels of impact were considered for the presence of the PEPs: a low-impact version in which the PEPs' presence only impacted 25% of the children at that site, a moderate-impact version in which the impact affected 50% of the children, and a high-impact version in which the impact affected 75% of the children. A secondary analysis was performed to account for the possibility of patients self-diverting from the closest ED to 1 of the pediatric EDs in the restrictive model., Results: In the restrictive model, the addition of 10 PEPs to the community would impact 27% of the pediatric ED care in the community. In the 3 distributive models, the PEPs would impact 23% of pediatric care in the low-impact version, 46% of pediatric care in the moderate-impact version, and 69% of pediatric care in the high-impact version. If self-diversion were to occur in the restrictive model, then 19% of the patients would need to bypass the closest ED and travel to the pediatric ED to match the same effect on patient care produced in the moderate-impact version of the distributive model and 46% would need to divert to match the effect of the high-impact version., Conclusions: The greatest impact of PEPs on an ED population of children is produced when the PEPs distribute themselves throughout a medical community rather than create individual pediatric EDs in a small number of hospitals.

Clinical course and histopathologic features of a typical case of familial hemophagocytic lymphohistiocytosis (FHLH) are presented. FHLH, initially known as familial hemophagocytic reticulosis (FHR), is rare and without proper treatment is invariably rapidly fatal, usually accompanied by fever, anorexia, vomiting, irritability and pallor. Sporadic examples with prolonged survival have been reported. Other significant findings include hepatosplenomegaly, progressive anemia, leukopenia, thrombocytopenia, hyperlipidemia and hypofibrinogenemia. Varying degrees of hemophagocytosis by widely disseminated histiocytes in different organs and structures is one hallmark of the disease. Hemophagocytosis may also occur in viral and bacterial infections and in certain malignant processes. Very high parental consanguinity in FHLH was mentioned in two relatively recent reports. A probable immunologic defect has been the focus of recent investigations. The genetic defect is believed to be transmitted as an autosomal recessive trait.