Changes in thymic regulatory T-cell maturation from birth to puberty: differences in atopic children

Prescription medication use after congenital heart surgery

BACKGROUND

Improvements in mortality after congenital heart surgery have necessitated a shift in focus to postoperative morbidity as an outcome measure. We examined late morbidity after congenital heart surgery based on prescription medication use.

METHODS

Between 1953 and 2009, 10,635 patients underwent congenital heart surgery at <15 years of age in Finland. We obtained 4 age-, sex-, birth-time, and hospital district-matched controls per patient. The Social Insurance Institution of Finland provided data on all prescription medications obtained between 1999 and 2012 by patients and controls. Patients were assigned one diagnosis based on a hierarchical list of cardiac defects and dichotomised into simple and severe groups. Medications were divided into short- and long-term based on indication. Follow-up started at the first operation and ended at death, emigration, or 31 December, 2012.

RESULTS

Totally, 8623 patients met inclusion criteria. Follow-up was 99.9%. In total, 8126 (94%) patients required prescription medications. Systemic anti-bacterials were the most common short-term prescriptions among patients (93%) and controls (88%). Patients required betablockers (simple hazard ratio 1.9, 95% confidence interval 1.7-2.1; severe hazard ratio 6.5, 95% confidence interval 5.3-8.1) and diuretics (simple hazard ratio 3.2, 95% CI 2.8-3.7; severe hazard ratio 38.8, 95% CI 27.5-54.7) more often than the general population. Both simple and severe defects required medication for cardiovascular, gastrointestinal, psychiatric, neurologic, metabolic, autoimmune, and infectious diseases more often than the general population.

CONCLUSIONS

The significant risk for postoperative cardiovascular and non-cardiovascular disease warrants close long-term follow-up after congenital heart surgery for all defects.

Distinct spatial and temporal roles for Th1, Th2, and Th17 cells in asthma

Immune response in the asthmatic respiratory tract is mainly driven by CD4⁺ T helper (Th) cells, represented by Th1, Th2, and Th17 cells, especially Th2 cells. Asthma is a heterogeneous and progressive disease, reflected by distinct phenotypes orchestrated by τh2 or non-Th2 (Th1 and Th17) immune responses at different stages of the disease course. Heterogeneous cytokine expression within the same Th effector state in response to changing conditions in vivo and interlineage relationship among CD4⁺ T cells shape the complex immune networks of the inflammatory airway, making it difficult to find one panacea for all asthmatics. Here, we review the role of three T helper subsets in the pathogenesis of asthma from different stages, highlighting timing is everything in the immune system. We also discuss the dynamic topography of Th subsets and pathogenetic memory Th cells in asthma.

Regulatory T Cells, a Viable Target Against Airway Allergic Inflammatory Responses in Asthma

Asthma is a multifactorial disorder characterized by the airway chronic inflammation, hyper-responsiveness (AHR), remodeling, and reversible obstruction. Although asthma is known as a heterogeneous group of diseases with various clinical manifestations, recent studies suggest that more than half of the clinical cases are ‘‘T helper type 2 (Th2)-high’’ type, whose pathogenesis is driven by Th2 responses to an inhaled allergen from the environmental exposures. The intensity and duration of inflammatory responses to inhaled allergens largely depend on the balance between effector and regulatory cells, but many questions regarding the mechanisms by which the relative magnitudes of these opposing forces are remained unanswered. Regulatory T cells (Tregs), which comprise diverse subtypes with suppressive function, have long been attracted extensive attention owing to their capability to limit the development and progression of allergic diseases. In this review we seek to update the recent advances that support an essential role for Tregs in the induction of allergen tolerance and attenuation of asthma progression once allergic airway inflammation established. We also discuss the current concepts about Treg induction and Treg-expressed mediators relevant to controlling asthma, and the therapies designed based on these novel insights against asthma in clinical settings.

Effect of puberty on the immune system: Relevance to multiple sclerosis

Puberty is a dynamic period marked by changing levels of sex hormones, the development of secondary sexual characteristics and reproductive maturity. This period has profound effects on various organ systems, including the immune system. The critical changes that occur in the immune system during pubertal onset have been shown to have implications for autoimmune conditions, including Multiple Sclerosis (MS). MS is rare prior to puberty but can manifest in children after puberty. This disease also has a clear female preponderance that only arises following pubertal onset, highlighting a potential role for sex hormones in autoimmunity. Early onset of puberty has also been shown to be a risk factor for MS. The purpose of this review is to overview the evidence that puberty regulates MS susceptibility and disease activity. Given that there is a paucity of studies that directly evaluate the effects of puberty on the immune system, we also discuss how the immune system is different in children and mice of pre- vs. post-pubertal ages and describe how gonadal hormones may regulate these immune mechanisms. We present evidence that puberty enhances the expression of co-stimulatory molecules and cytokine production by type 2 dendritic cells (DC2s) and plasmacytoid dendritic cells (pDCs), increases T helper 1 (Th1), Th17, and T follicular helper immunity, and promotes immunoglobulin (Ig)G antibody production. Overall, this review highlights how the immune system undergoes a functional maturation during puberty, which has the potential to explain the higher prevalence of MS and other autoimmune diseases seen in adolescence.

Favorable prognosis of vaccine-associated immune thrombocytopenia in children is correlated with young age at vaccination: Retrospective survey of a nationwide disease registry

Childhood vaccine-associated immune thrombocytopenia (ITP) has a mostly favorable prognosis. To identify factors associated with prognosis, a retrospective survey was conducted with children with ITP who were registered in the Japanese Society of Pediatric Hematology/Oncology registry from 2008 to 2011. A total of 477 patients were categorized into four groups by event preceding ITP onset: vaccine-precedence (VP; n = 43), vaccine/infection-precedence (VIP; n = 34), infection-precedence (IP; n = 162), and no vaccine/infection-precedence (NVI; n = 238). Compared to IP and NVI, VP and VIP were significantly younger at diagnosis, with the age distribution peaking at infancy, and more frequently had favorable prognosis. Time to platelet recovery to 100 × 10³/µL was significantly faster for VP and VIP than NVI. Multivariate Cox regression analysis with sex, age at diagnosis, infection-precedence, and vaccine-precedence as variables revealed age < 36 months (HR 0.992, 95% CI 0.989-0.995; p < 0.001) and male sex (HR 0.770, 95% CI 0.623-0.952; p = 0.015) as associated factors, but not infection-precedence (p = 0.149) or vaccine-precedence (p = 0.650). In subgroup analysis in patients < 36 months, age at diagnosis (p < 0.001) was the only associated factor. Favorable prognosis of childhood vaccine-associated ITP is correlated with young age at vaccination, but not with vaccination itself.

Respiratory Viral and Bacterial Factors That Influence Early Childhood Asthma

Asthma is a chronic respiratory condition characterised by episodes of shortness of breath due to reduced airway flow. The disease is triggered by a hyperreactive immune response to innocuous allergens, leading to hyper inflammation, mucus production, changes in structural cells lining the airways, and airway hyperresponsiveness. Asthma, although present in adults, is considered as a childhood condition, with a total of about 6.2 million children aged 18 and below affected globally. There has been progress in understanding asthma heterogeneity in adults, which has led to better patient stratification and characterisation of multiple asthma endotypes with distinct, but overlapping inflammatory features. The asthma inflammatory profile in children is not well-defined and heterogeneity of the disease is less described. Although many factors such as genetics, food allergies, antibiotic usage, type of birth, and cigarette smoke exposure can influence asthma development particularly in children, respiratory infections are thought to be the major contributing factor in poor lung function and onset of the disease. In this review, we focus on viral and bacterial respiratory infections in the first 10 years of life that could influence development of asthma in children. We also review literature on inflammatory immune heterogeneity in asthmatic children and how this overlaps with early lung development, poor lung function and respiratory infections. Finally, we review animal studies that model early development of asthma and how these studies could inform future therapies and better understanding of this complex disease.

Functionally specialized human CD4+ T-cell subsets express physicochemically distinct TCRs

The organizational integrity of the adaptive immune system is determined by functionally discrete subsets of CD4⁺ T cells, but it has remained unclear to what extent lineage choice is influenced by clonotypically expressed T-cell receptors (TCRs). To address this issue, we used a high-throughput approach to profile the αβ TCR repertoires of human naive and effector/memory CD4⁺ T-cell subsets, irrespective of antigen specificity. Highly conserved physicochemical and recombinatorial features were encoded on a subset-specific basis in the effector/memory compartment. Clonal tracking further identified forbidden and permitted transition pathways, mapping effector/memory subsets related by interconversion or ontogeny. Public sequences were largely confined to particular effector/memory subsets, including regulatory T cells (Tregs), which also displayed hardwired repertoire features in the naive compartment. Accordingly, these cumulative repertoire portraits establish a link between clonotype fate decisions in the complex world of CD4⁺ T cells and the intrinsic properties of somatically rearranged TCRs.

The Metabolic Changes and Immune Profiles in Patients With COVID-19

To explore the metabolic changes and immune profiles in patients with COVID-19, we analyzed the data of patients with mild and severe COVID-19 as well as young children with COVID-19. Of the leukocytes, 47% (IQR, 33-59) were lymphocytes [2.5 × 10⁹/L (IQR, 2.2-3.3)], and monocytes were 0.51 × 10⁹/L (IQR, 0.45-0.57) in young children with COVID-19. In 32 mild COVID-19 patients, circulating monocytes were 0.45 × 10⁹/L (IQR, 0.36-0.64). Twenty-one severe patients had low PO₂ [57 mmHg (IQR, 50-73)] and SO₂ [90% (IQR, 86-93)] and high lactate dehydrogenase [580 U/L (IQR, 447-696)], cardiac troponin I [0.07 ng/mL (IQR, 0.02-0.30)], and pro-BNP [498 pg/mL (IQR, 241-1,726)]. Serum D-dimer and FDP were 9.89 mg/L (IQR, 3.62-22.85) and 32.7 mg/L (IQR, 12.8-81.9), and a large number of RBC (46/μL (IQR, 4-242) was presented in urine, a cue of disseminated intravascular coagulation (DIC) in severe patients. Three patients had comorbidity with diabetes, and 18 patients without diabetes also presented high blood glucose [7.4 mmol/L (IQR, 5.9-10.1)]. Fifteen of 21 (71%) severe cases had urine glucose +, and nine of 21 (43%) had urine ketone body +. The increased glucose was partially caused by reduced glucose consumption of cells. Severe cases had extraordinarily low serum uric acid [176 μmol/L (IQR, 131-256)]. In the late stage of COVID-19, severe cases had extremely low CD4⁺ T cells and CD8⁺ T cells, but unusually high neutrophils [6.5 × 10⁹/L (IQR, 4.8-9.6)], procalcitonin [0.27 ng/mL (IQR, 0.14-1.94)], C-reactive protein [66 mg/L (IQR, 25-114)] and an extremely high level of interleukin-6. Four of 21 (19%) severe cases had co-infection with fungi, and two of 21 (9%) severe cases had bacterial infection. Our findings suggest that, severe cases had acute respiratory distress syndrome (ARDS) I-III, and metabolic disorders of glucose, lipid, uric acid, etc., even multiple organ dysfunction (MODS) and DIC. Increased neutrophils and severe inflammatory responses were involved in ARDS, MODS, and DIC. With the dramatical decrease of T-lymphocytes, severe cases were susceptible to co-infect with bacteria and fungi in the late stage of COVID-19. In young children, extremely high lymphocytes and monocytes might be associated with the low morbidity of COVID-19. The significantly increased monocytes might play an important role in the recovery of patients with mild COVID-19.

Pharmacokinetics and Clinical Pharmacology of Monoclonal Antibodies in Pediatric Patients

Monoclonal antibodies (mAbs) and their derivatives are increasingly used in pediatric pharmacotherapy, and the number of antibody-based drug products with approved pediatric indications is continuously growing. In most instances, pediatric use is being pursued after the efficacy and safety of novel antibody medications have been established in adult indications. The pediatric extrapolation exercise that is frequently used in this context to bridge efficacy and safety from adults to children is oftentimes challenged through uncertainties and knowledge gaps in how to reliably extrapolate pharmacokinetics and clinical pharmacology of mAbs to different pediatric age groups, and how to derive age-appropriate dosing regimens that strike a balance between precision dosing and practicability. The article highlights some of the pharmacokinetic and clinical pharmacology challenges with regard to therapeutic use of mAbs and antibody derivatives in children, including immunogenicity events. Although considering body size-based differences in drug disposition can account for many of the perceived and actual differences in the distribution and elimination of antibody-based therapeutics between children and adults, increasing evidence suggests potential or actual age-associated differences beyond size differences, especially for young pediatric patients such as newborns and infants. To overcome age-associated differences in antibody disposition, various different dosing approaches have been applied to ensure safe and efficacious antibody exposure for pediatric populations of different ages. The development of such dosing regimens and the associated pathway to pediatric indication approval is illustrated in more detail for two antibody-based biologics, the fusion protein abatacept and the mAb tocilizumab.

Environment and Host-Genetic Determinants in Early Development of Allergic Asthma: Contribution of Fungi

Asthma is a chronic debilitating airway disease affecting millions of people worldwide. Although largely thought to be a disease of the first world, it is now clear that it is on the rise in many middle- and lower-income countries. The disease is complex, and its etiology is poorly understood, which explains failure of most treatment strategies. We know that in children, asthma is closely linked to poor lung function in the first 3-years of life, when the lung is still undergoing post-natal alveolarization phase. Epidemiological studies also suggest that environmental factors around that age do play a critical part in the establishment of early wheezing which persists until adulthood. Some of the factors that contribute to early development of asthma in children in Western world are clear, however, in low- to middle-income countries this is likely to differ significantly. The contribution of fungal species in the development of allergic diseases is known in adults and in experimental models. However, it is unclear whether early exposure during perinatal or post-natal lung development influences a protective or promotes allergic asthma. Host immune cells and responses will play a crucial part in early development of allergic asthma. How immune cells and their receptors may recognize fungi and promote allergic asthma or protect by tolerance among other immune mechanisms is not fully understood in this early lung development stage. The aim of this review is to discuss what fungal species are present during early exposure as well as their contribution to the development of allergic responses. We also discuss how the host has evolved to promote tolerance to limit hyper-responsiveness to innocuous fungi, and how host evasion by fungi during early development consequentially results in allergic diseases.

Inception of early-life allergen-induced airway hyperresponsiveness is reliant on IL-13+CD4+ T cells

Airway hyperresponsiveness (AHR) is a critical feature of wheezing and asthma in children, but the initiating immune mechanisms remain unconfirmed. We demonstrate that both recombinant interleukin-33 (rIL-33) and allergen [house dust mite (HDM) or Alternaria alternata] exposure from day 3 of life resulted in significantly increased pulmonary IL-13⁺CD4⁺ T cells, which were indispensable for the development of AHR. In contrast, adult mice had a predominance of pulmonary Lin^negCD45⁺CD90⁺IL-13⁺ type 2 innate lymphoid cells (ILC2s) after administration of rIL-33. HDM exposure of neonatal IL-33 knockout (KO) mice still resulted in AHR. However, neonatal CD4^creIL-13 KO mice (lacking IL-13⁺CD4⁺ T cells) exposed to allergen from day 3 of life were protected from AHR despite persistent pulmonary eosinophilia, elevated IL-33 levels, and IL-13⁺ ILCs. Moreover, neonatal mice were protected from AHR when inhaled Acinetobacter lwoffii (an environmental bacterial isolate found in cattle farms, which is known to protect from childhood asthma) was administered concurrent with HDM. A. lwoffii blocked the expansion of pulmonary IL-13⁺CD4⁺ T cells, whereas IL-13⁺ ILCs and IL-33 remained elevated. Administration of A. lwoffii mirrored the findings from the CD4^creIL-13 KO mice, providing a translational approach for disease protection in early life. These data demonstrate that IL-13⁺CD4⁺ T cells, rather than IL-13⁺ ILCs or IL-33, are critical for inception of allergic AHR in early life.

M1-like macrophage polarization prevails in young children with classic Hodgkin Lymphoma from Argentina

The microenvironment in classical Hodgkin lymphoma (cHL) comprises a mixture of different types of cells, which are responsible for lymphoma pathogenesis and progression. Even though microenvironment composition in adult cHL has been largely studied, only few groups studied pediatric cHL, in which both Epstein Barr virus (EBV) infection and age may display a role in their pathogenesis. Furthermore, our group described that EBV is significantly associated with cHL in Argentina in patients under the age of 10 years old. For that reason, our aim was to describe the microenvironment composition in 46 pediatric cHL patients. M1-like polarization status prevailed in the whole series independently of EBV association. On the other hand, in children older than 10 years, a tolerogenic environment illustrated by higher FOXP3 expression was proved, accompanied by a macrophage polarization status towards M2. In contrast, in children younger than 10 years, M1-like was prevalent, along with an increase in cytotoxic GrB+ cells. This study supports the notion that pediatric cHL exhibits a particular tumor microenvironment composition.

Prebiotics: Mechanisms and Preventive Effects in Allergy

Allergic diseases now affect over 30% of individuals in many communities, particularly young children, underscoring the need for effective prevention strategies in early life. These allergic conditions have been linked to environmental and lifestyle changes driving the dysfunction of three interdependent biological systems: microbiota, epithelial barrier and immune system. While this is multifactorial, dietary changes are of particular interest in the altered establishment and maturation of the microbiome, including the associated profile of metabolites that modulate immune development and barrier function. Prebiotics are non-digestible food ingredients that beneficially influence the health of the host by 1) acting as a fermentable substrate for some specific commensal host bacteria leading to the release of short-chain fatty acids in the gut intestinal tract influencing many molecular and cellular processes; 2) acting directly on several compartments and specifically on different patterns of cells (epithelial and immune cells). Nutrients with prebiotic properties are therefore of central interest in allergy prevention for their potential to promote a more tolerogenic environment through these multiple pathways. Both observational studies and experimental models lend further credence to this hypothesis. In this review, we describe both the mechanisms and the therapeutic evidence from preclinical and clinical studies exploring the role of prebiotics in allergy prevention.

Temporal and long-term gut microbiota variation in allergic disease: A prospective study from infancy to school age

BACKGROUND

Compositional changes in the early-life gut microbiota have been implicated in IgE-associated allergic diseases, but there is lack of longitudinal studies. We examined gut microbiota development from infancy to school age in relation to onset of IgE-associated allergic diseases. At 8 years of age, we also examined the relationship between gut microbiota and T-cell regulation, estimated as responses to polyclonal T-cell activation.

METHODS

Stool samples were collected from 93 children at 4, 6, 13 months, and 8 years of age. The gut microbiota was profiled using 16S rRNA gene sequencing. Peripheral blood was drawn from all children, and mononuclear cells were polyclonally activated. Levels of IL-10 and FOXP3 mRNA copies were determined using real-time quantitative reverse transcriptase-PCR.

RESULTS

At 8 years of age, 21 children were diagnosed with IgE-associated allergic disease and 90% displayed allergic comorbidity. Seventy-two children were nonallergic and nonsensitized. Statistical tests with multiple testing corrections demonstrated temporal underrepresentation of Ruminococcus and consistent underrepresentation of Bacteroides, Prevotella, and Coprococcus in allergic compared to nonallergic children from infancy to school age. The gut microbiota of the allergic 8-year-olds was enriched in Bifidobacterium and depleted of Lactobacillus, Enterococcus, and Lachnospira. In allergic 8-year-olds, Faecalibacterium correlated with IL-10 mRNA levels (r_s  = 0.49_, P_adj  = 0.02) with the same trend for FOXP3 (r_s  = 0.39_, P_adj  = 0.08).

CONCLUSIONS

We identified both temporal and long-term variation in the differential abundance of specific bacterial genera in children developing IgE-associated allergic disease. Improved dietary interventions aiming at expanding immune-modulatory taxa could be studied for prevention of allergic disease.

Epigenetic regulation of T-helper cell differentiation, memory, and plasticity in allergic asthma

An estimated 300 million people currently suffer from asthma, which causes approximately 250 000 deaths a year. Allergen-specific T-helper (Th) cells produce cytokines that induce many of the hallmark features of asthma including airways hyperreactivity, eosinophilic and neutrophilic inflammation, mucus hypersecretion, and airway remodeling. Cytokine-producing Th subsets including Th1 (IFN-γ), Th2 (IL-4, IL-5, IL-13), Th9 (IL-9), Th17 (IL-17), Th22 (IL-22), and T regulatory (IL-10) cells have all been suggested to play a role in the development of asthma. Th differentiation involves genetic regulation of gene expression through the concerted action of cytokines, transcription factors, and epigenetic regulators. We describe how Th differentiation and plasticity is regulated by epigenetic histone and DNA modifications, with a focus on the regulation of histone methylation by members of the polycomb and trithorax complexes. In addition, we outline environmental influences that could influence epigenetic regulation of Th cells and discuss the potential to regulate Th plasticity and function through drugs targeting the epigenetic machinery. It is also becoming apparent that epigenetic regulation of allergen-specific memory Th cells may be important in the development and persistence of chronic allergies. Finally, we describe how epigenetic modifiers regulate cytokine memory in Th cells and describe recently identified hybrid, plastic, and pathogenic memory Th subsets the context of allergic asthma.

Effect of puberty on multiple sclerosis risk and course

Puberty occurs over several years and is a time of major sex hormone changes. These changes impact many physiological functions including immune system maturation. This review details the current understanding of the impact of puberty on the risk to develop multiple sclerosis (MS) and the age at which it occurs, as well as its effect on the risk of relapses.

A switch in regulatory T cells through farm exposure during immune maturation in childhood

BACKGROUND

Farm exposure protects against development of allergies early in life. At 4.5 years, protection against asthma by farm-milk exposure was partially mediated by regulatory T cells (Tregs). The aim of this study was to investigate the critical time window of the 'asthma-protective' farm effect via Tregs during childhood immune maturation.

METHODS

Tregs were assessed longitudinally at 4.5 and 6 years in 111 children (56 farm and 55 reference children) from the PASTURE/EFRAIM birth cohort (flow cytometry). Peripheral blood mononuclear cells were cultured unstimulated (U), with phorbol 12-myristate 13-acetate/ionomycin (PI) or lipopolysaccharide (LPS), and stained for Tregs (CD4⁺ CD25^high FOXP3^upper20% ). mRNA expression of Treg/Th1/Th2/Th17-associated cell markers was measured ex vivo. Suppressive capacity of Tregs on effector cells and cytokines was assessed. Detailed questionnaires assessing farm exposures and clinical phenotypes from birth until age 6 years were answered by the parents.

RESULTS

Treg percentage before and after stimulation and FOXP3mRNA expression ex vivo decreased from age 4.5 to 6 years (P(U,LPS) < 0.001; P(PI) = 0.051; P(FOXP3) < 0.001). High vs low farm-milk and animal-stable exposure was associated with decreased LPS-stimulated Treg percentage at age 6 years (P(LPS) = 0.045). Elevated LPS-stimulated-Treg percentage at age 6 was associated with increased risk of asthma (aOR = 11.29, CI: 0.96-132.28, P = 0.053). Tregs from asthmatics vs nonasthmatics suppressed IFN-γ (P = 0.015) and IL-9 (P = 0.023) less efficiently. mRNA expression of Th1/Th2/Th17-associated cell markers decreased between 4.5 and 6 years (P < 0.001).

CONCLUSIONS

Tregs at the age of 6 years were decreased with farm exposure and increased within asthmatics, opposite to age 4.5 years. This immunological switch defines a critical 'time window' for Treg-mediated asthma protection via environmental exposure before age 6 years.

Vitamin D and multiple sclerosis: An update

The most recent findings linking exposure to sun and vitamin D insufficiency to multiple sclerosis (MS) are reviewed. Due to insufficient sunshine and changing lifestyles, hypovitaminosis D is widespread in temperate countries. Numerous epidemiological studies have strongly suggested that sunshine and vitamin D insufficiency contributes to MS risk in these countries. Moreover, several large genetic studies in MS patients have recently stated unequivocally that diverse abnormalities involving vitamin D metabolism are related to the risk of the disease. The important implications of such results are discussed here. Then, the interactions of hypovitaminosis D with the other genetic and environmental protective and risk factors, such as the allele HLA DRB1*1501, Epstein-Barr virus infection, obesity, smoking and sexual hormones, are summarized. Vitamin D insufficiency and sufficiency could be a risk and a protective factor, respectively, among many other factors possibly continuously modulating the global MS risk from the mother's pregnancy to the triggering of MS in adulthood. However, many interactions between these different factors occur more particularly between conception and the end of adolescence, which corresponds to the period of maturation of the immune system and thymus and may be related to the dysimmune nature of the disease. The main mechanisms of action of vitamin D in MS appear to be immunomodulatory, involving the various categories of T and B lymphocytes in the general immune system, but neuroprotector and neurotrophic mechanisms could also be exerted at the central nervous system level. Furthermore, several controlled immunological studies performed in MS patients have recently confirmed that vitamin D supplementation has multiple beneficial immunomodulatory effects. However, there is still an enduring absence of major conclusive randomized clinical trials testing vitamin D supplementation in MS patients because of the quasi-insurmountable practical difficulties that exist nowadays in conducting and completing over several years such studies involving the use of a vitamin. Nevertheless, it should be noted that similar robust statistical models used in five different association studies have already predicted a favorable vitamin D effect reducing relapses by 50-70%. If there is now little doubt that vitamin D exerts a beneficial action on the inflammatory component of MS, the results are as yet much less clear for the progressive degenerative component. Lastly, until more information becomes available, vitamin D supplementation of MS patients, using a moderate physiological dose essentially correcting their vitamin insufficiency, is recommended.

The role of PKCζ in cord blood T-cell maturation towards Th1 cytokine profile and its epigenetic regulation by fish oil

While immunodeficiency of immaturity of the neonate has been considered important as the basis for unusual susceptibility to infection, it has also been recognized that the ability to progress from an immature Th2 cytokine predominance to a Th1 profile has relevance in determining whether children will develop allergy, providing an opportunity for epigenetic regulation through environmental pressures. However, this notion remains relatively unexplored. Here, we present evidence that there are two major control points to explain the immunodeficiency in cord blood (CB) T-cells, a deficiency in interleukin (IL)-12 (IL-12) producing and IL-10 overproducing accessory cells, leading to a decreased interferon γ (IFNγ) synthesis and the other, an intrinsic defect in T-cell protein kinase C (PKC) ζ (PKCζ) expression. An important finding was that human CB T-cells rendered deficient in PKCζ, by shRNA knockdown, develop into low tumour necrosis factor α (TNFα) and IFNγ but increased IL-13 producing cells. Interestingly, we found that the increase in PKCζ levels in CB T-cells caused by prenatal supplementation with fish oil correlated with modifications of histone acetylation at the PKCζ gene (PRKCZ) promoter. The data demonstrate that PKCζ expression regulates the maturation of neonatal T-cells into specific functional phenotypes and that environmental influences may work via PKCζ to regulate these phenotypes and disease susceptibility.

Regulatory T Cells in Allergy and Asthma

The immune system's correct functioning requires a sophisticated balance between responses to continuous microbial challenges and tolerance to harmless antigens, such as self-antigens, food antigens, commensal microbes, allergens, etc. When this equilibrium is altered, it can lead to inflammatory pathologies, tumor growth, autoimmune disorders, and allergy/asthma. The objective of this review is to show the existing data on the importance of regulatory T cells (Tregs) on this balance and to underline how intrauterine and postnatal environmental exposures influence the maturation of the immune system in humans. Genetic and environmental factors during embryo development and/or early life will result in a proper or, conversely, inadequate immune maturation with either beneficial or deleterious effects on health. We have focused herein on Tregs as a reflection of the maturity of the immune system. We explain the types, origins, and the mechanisms of action of these cells, discussing their role in allergy and asthma predisposition. Understanding the importance of Tregs in counteracting dysregulated immunity would provide approaches to diminish asthma and other related diseases in infants.

Planting the seed: Origins, composition, and postnatal health significance of the fetal gastrointestinal microbiota

It has long been assumed that establishment of the fetal microbiome commences with the birthing process. However, recent studies have found bacterial DNA in umbilical cord blood, placenta, amniotic fluid, meconium, and fetal membranes in healthy normal pregnancies, leading to suggestions that the seeding of the fetal microbiome may commence in utero long before delivery. The origins of the microbiota of the fetal gastrointestinal (GI) tract have not yet been conclusively determined, although bacterial translocation from the maternal circulation, or ascension from the vagina, are both likely to be contributing pathways. Mother-to-child efflux of bacteria during pregnancy has the potential to markedly influence postnatal health, as the composition of gut microbiota determines production of important metabolites which are absorbed systemically and which modify immune function and development. Hence, the importance of understanding the colonization of the fetal GI microbiome is becoming clear, although few studies have investigated the origins, dynamics, and timing of the fetal microbiome. This is the topic of this review. By gaining a deeper understanding of the mechanisms underpinning fetal microbiome seeding, strategies may be developed to optimize fetal immune development and reduce the risk of adverse health and developmental outcomes.

Allergies - A T cells perspective in the era beyond the TH1/TH2 paradigm

Allergic diseases have emerged as a major health care burden, especially in the western hemisphere. They are defined by overshooting reactions of an aberrant immune system to harmless exogenous stimuli. The T_H1/T_H2 paradigm assumes that a dominance of T_H2 cell activation and an inadequate T_H1 cell response are responsible for the development of allergies. However, the characterization of additional T helper cell subpopulations such as T_H9, T_H17, T_H22, T_HGM-CSF and their interplay with regulatory T cells suggest further layers of complexity. This review summarizes state-of-the-art knowledge on T cell diversity and their induction, while revisiting the T_H1/T_H2 paradigm. With respect to these numerous contributors, it offers a new perspective on the pathogenesis of asthma, allergic rhinitis (AR) and atopic dermatitis (AD) incorporating recent discoveries in the field of T cell plasticity.

Immune-Microbiota Interactions: Dysbiosis as a Global Health Issue

Throughout evolution, microbial genes and metabolites have become integral to virtually all aspects of host physiology, metabolism and even behaviour. New technologies are revealing sophisticated ways in which microbial communities interface with the immune system, and how modern environmental changes may be contributing to the rapid rise of inflammatory noncommunicable diseases (NCDs) through declining biodiversity. The implications of the microbiome extend to virtually every branch of medicine, biopsychosocial and environmental sciences. Similarly, the impact of changes at the immune-microbiota interface are directly relevant to broader discussions concerning rapid urbanization, antibiotics, agricultural practices, environmental pollutants, highly processed foods/beverages and socioeconomic disparities--all implicated in the NCD pandemic. Here, we make the argument that dysbiosis (life in distress) is ongoing at a micro- and macro-scale and that as a central conduit of health and disease, the immune system and its interface with microbiota is a critical target in overcoming the health challenges of the twenty-first century.

Atopic dermatitis induces the expansion of thymus-derived regulatory T cells exhibiting a Th2-like phenotype in mice

Atopic dermatitis (AD) is a widespread inflammatory skin disease with an early onset, characterized by pruritus, eczematous lesions and skin dryness. This chronic relapsing disease is believed to be primarily a result of a defective epidermal barrier function associated with genetic susceptibility, immune hyper-responsiveness of the skin and environmental factors. Although the important role of abnormal immune reactivity in the pathogenesis of AD is widely accepted, the role of regulatory T cells (Tregs) remains elusive. We found that the Treg population is expanded in a mouse model of AD, i.e. mice topically treated with vitamin D3 (VitD). Moreover, mice with AD-like symptoms exhibit increased inducible T-cell costimulator (ICOS)-, cytotoxic T-lymphocyte antigen-4 (CTLA-4)- and Glycoprotein-A repetitions predominant receptor (GARP)-expressing Tregs in skin-draining lymph nodes. Importantly, the differentiation of Tregs into thymus-derived Tregs is favoured in our mouse model of AD. Emigrated skin-derived dendritic cells are required for Treg induction and Langerhans cells are responsible for the biased expansion of thymus-derived Tregs . Intriguingly, thymus-derived Tregs isolated from mice with AD-like symptoms exhibit a Th2 cytokine profile. Thus, AD might favour the expansion of pathogenic Tregs able to produce Th2 cytokines and to promote the disease instead of alleviating symptoms.

Early farm residency and prevalence of asthma and hay fever in adults

BACKGROUND

Asthma and hay fever have been found to be both positively and negatively associated with farming lifestyles in adulthood. Lack of congruency may depend upon early life exposure.

OBJECTIVE

To assess the importance of different periods of farm residency for asthma and hay fever in an adult Canadian population.

METHODS

We conducted a questionnaire survey in rural Saskatchewan, Canada. We assessed a history of asthma and hay fever with five categories of farm residency that were mutually exclusive: first year of life only, currently living on a farm, both first year of life and currently living on a farm, other farm living, and no farm living. Generalized estimating equations were used to adjust for clustering effects of adults within households.

RESULTS

Of the 7148 responding, 30.6% had an early farm living experience only, 34.4% had both early and current farm living experiences, while 17.4% had never lived on a farm. The overall prevalence of ever asthma and hay fever was 8.6% and 12.3%, respectively, and was higher in women. Sex modified the associations between ever asthma and hay fever with farm residency variables whereby women had a decreased risk for both asthma [adjusted odds ratio (ORadj): 0.67, 95% confidence interval (CI):0.47-0.96] and hay fever (ORadj: 0.60, 95% CI: 0.44-0.83) with an early farm exposure only. Men currently living on a farm without an early farm exposure had an increased risk for ever asthma (ORadj: 1.82, 95% CI: 1.02-3.24).

CONCLUSION

Farm residency in the first year of life shows a protective effect for adult asthma and hay fever that appears to differ by sex.

The gut microbiota and its role in the development of allergic disease: a wider perspective

The gut microbiota are critical in the homoeostasis of multiple interconnected host metabolic and immune networks. If early microbial colonization is delayed, the gut-associated lymphoid tissues (GALT) fail to develop, leading to persistent immune dysregulation in mice. Microbial colonization has also been proposed as a major driver for the normal age-related maturation of both Th1 and T regulatory (Treg) pathways that appear important in suppressing early propensity for Th2 allergic responses. There is emerging evidence that resident symbionts induce tolerogenic gut-associated Treg cells and dendritic cells that ensure the preferential growth of symbionts; keeping pathogenic strains in check and constraining proinflammatory Th1, Th2, and Th17 clones. Some effects of symbionts are mediated by short-chain fatty acids, which play a critical role in mucosal integrity and local and systemic metabolic function and stimulate the regulatory immune responses. The homoeostatic IL-10/TGF-β dominated tolerogenic response within the GALT also signals the production of secretory IgA, which have a regulating role in mucosal integrity. Contrary to the 'sterile womb' paradigm, recent studies suggest that maternal microbial transfer to the offspring begins during pregnancy, providing a pioneer microbiome. It is likely that appropriate microbial stimulation both pre- and postnatally is required for optimal Th1 and Treg development to avoid the pathophysiological processes leading to allergy. Disturbed gut colonization patterns have been associated with allergic disease, but whether microbial variation is the cause or effect of these diseases is still under investigation. We are far from understanding what constitutes a 'healthy gut microbiome' that promotes tolerance. This remains a major limitation and might explain some of the inconsistency in human intervention studies with prebiotics and probiotics. Multidisciplinary integrative approaches with researchers working in networks, using harmonized outcomes and methodologies, are needed to advance our understanding in this field.

Anti-dentine Salivary SIgA in young adults with a history of dental trauma in deciduous teeth

Anti-dentin autoantibodies are associated with inflammatory root resorption in permanent teeth and are modulated by dental trauma and orthodontic force. However, it is not known whether deciduous tooth trauma can stimulate the development of a humoral immune response against dentin. The aim of this study was to evaluate the levels of salivary SIgA reactivity against human dentin extract in young adults with a history of trauma in the primary dentition. A sample of 78 patients, aged 18 to 25, who had completed an early childhood (0 to 5 years old) caries prevention program years earlier at the Universidade Estadual de Londrina Pediatric Clinic, underwent radiographic examination and salivary sampling. Anti-dentin SIgA levels were analyzed by immunoenzymatic assay and Western blotting. Although dental trauma to deciduous teeth had occurred in 34 (43.6%) of the patients, no differences in SIgA levels were detected between individuals who had experienced trauma and those who had not (p > 0.05). Multivariate regression analysis showed no association between dental trauma and SIgA levels (p > 0.05). Patients with a history of deciduous trauma presented low levels of anti-dentin antibodies, associated with orthodontic root resorption (p < 0.05). Western blot analysis showed that salivary antibodies recognized a single band of approximately 45 kDa in dentin extract. We concluded that salivary SIgA recognizes a specific component of the dentin matrix and that anti-dentin antibodies were not triggered by trauma to primary teeth. However, trauma to deciduous teeth may down-modulate SIgA in response to orthodontic root response.

Is the developmentally immature immune response in paediatric sepsis a recapitulation of immune tolerance?

Immunologically immature neonates suffer the highest incidence of paediatric sepsis. Postnatal immunological maturation is characterized by a relatively hypo-inflammatory immune response. The mechanisms that differentiate the mature and immature immune responses resemble those that differentiate the hyper- and hypo-inflammatory responses in severe sepsis. Immunological maturational differences likely affect the neonate's ability to mount an appropriate hyper-inflammatory response, a counteractive hypo-inflammatory response, and subsequent return to immune system homeostasis. To better understand the role of the hypo-inflammatory response in paediatric sepsis, we will explore the maturation of the immune system and the effect it may have on the sepsis-induced hypo-inflammatory response.

Controlled trials of vitamin D, causality and type 2 statistical error

Two recent studies published in The Lancet (Autier et al. (2013) Lancet Diabetes Endocrinol 2, 76-89 and Bolland et al. (2014) Lancet Diabetes Endocrinol 2, 307-320) have concluded that low levels of vitamin D are not a cause but a consequence of ill health brought about by reduced exposure to the sun, an association known as 'reverse causality'. The scientific evidence and reasoning for these conclusions are examined here and found to be faulty. A null result in a clinical trial of vitamin D in adults need not lead to a conclusion of reverse causation when low vitamin D is found in observational studies of the same disease earlier in life. To assume an explanation of reverse causality has close similarities with type 2 statistical error. For example, a null result in providing vitamin D for treatment of adult bones that are deformed in the pattern of the rachitic rosary would not alter the observation that lack of vitamin D can cause rickets in childhood and may have lasting consequences if not cured with vitamin D. Other examples of diseases considered on a lifetime basis from conception to adulthood are used to further illustrate the issue, which is evidently not obvious and is far from trivial. It is concluded that deficiency of vitamin D in cohort studies, especially at critical times such as pregnancy and early life, can be the cause of a number of important diseases. Denial of the possible benefits of vitamin D, as suggested by insistent interpretation of studies with reverse causation, may lead to serious harms, some of which are listed.

Human thymus medullary epithelial cells promote regulatory T-cell generation by stimulating interleukin-2 production via ICOS ligand

Natural thymic T regulatory (tTreg) cells maintain tolerance to self-antigen. These cells are generated in the thymus, but how this generation occurs is still controversial. Furthermore, the contribution of thymus epithelial cells to this process is still unclear, especially in humans. Using an exceptional panel of human thymic samples, we demonstrated that medullary thymus epithelial cells (mTECs) promote the generation of tTreg cells and favor their function. These effects were mediated through soluble factors and were mTEC specific since other cell types had no such effect. By evaluating the effects of mTECs on the absolute number of Treg cells and their state of proliferation or cell death, we conclude that mTECs promote the proliferation of newly generated CD25+ cells from CD4+CD25- cells and protect Treg cells from cell death. This observation implicates Bcl-2 and mitochondrial membrane potential changes, indicating that the intrinsic cell death pathway is involved in Treg protection by mTECs. Interestingly, when the mTECs were cultured directly with purified Treg cells, they were able to promote their phenotype but not their expansion, suggesting that CD4+CD25- cells have a role in the expansion process. To explore the mechanisms involved, several neutralizing antibodies were tested. The effects of mTECs on Treg cells were essentially due to interleukin (IL)-2 overproduction by thymus CD4+ T cells. We then searched for a soluble factor produced by mTECs able to increase IL-2 production by CD4+ cells and could identify the inducible T-cell costimulator ligand (ICOSL). Our data strongly suggest a « ménage à trois »: mTEC cells (via ICOSL) induce overproduction of IL-2 by CD25- T cells leading to the expansion of tTreg cells. Altogether, these results demonstrate for the first time a role of mTECs in promoting Treg cell expansion in the human thymus and implicate IL-2 and ICOSL in this process.

Children with chronic suppurative lung disease have a reduced capacity to synthesize interferon-gamma in vitro in response to non-typeable Haemophilus influenzae

Chronic suppurative lung disease (CSLD) is characterized by the presence of a chronic wet or productive cough and recurrent lower respiratory infections. The aim of this study was to identify features of innate, cell-mediated and humoral immunity that may increase susceptibility to respiratory infections in children with CSLD. Because non-typeable Haemophilus influenzae (NTHi) is commonly isolated from the airways in CSLD, we examined immune responses to this organism in 80 age-stratified children with CSLD and compared their responses with 51 healthy control children. Cytokines involved in the generation and control of inflammation (IFN-γ, IL-13, IL-5, IL-10 at 72 hours and TNFα, IL-6, IL-10 at 24 hours) were measured in peripheral blood mononuclear cells challenged in vitro with live NTHi. We also measured circulating IgG subclass antibodies (IgG₁ and IgG₄) to two H. influenzae outer membrane proteins, P4 and P6. The most notable finding was that PBMC from children with CSLD produced significantly less IFN-γ in response to NTHi than healthy control children whereas mitogen-induced IFN-γ production was similar in both groups. Overall there were minor differences in innate and humoral immune responses between CSLD and control children. This study demonstrates that children with chronic suppurative lung disease have an altered systemic cell-mediated immune response to NTHi in vitro. This deficient IFN-γ response may contribute to increased susceptibility to NTHi infections and the pathogenesis of CSLD in children.

Influence of maternal immunization with allergens on the thymic maturation of lymphocytes with regulatory potential in children: a broad field for further exploration

A variety of mechanisms are involved in the regulation of offspring allergy development through maternal immunization with allergens. The passive transfer of antigens, antibodies, and cytokines, the induction of phenotypic alterations in offspring lymphocytes, and the induction of regulatory populations in offspring have been proposed, but these mechanisms remain incompletely understood. It is likely that maternal immunization could affect the intrathymic maturation of offspring TCD4+, TCD8+, γδT, nTreg, iNKT, and B lymphocytes, although there are currently no human maternal immunization protocols for the regulation of allergic responses in children. Some studies have suggested a direct interaction between the maternal immune status and the offspring intrathymic microenvironment; this interaction could influence the maturation of offspring regulatory cells and must be explored for the development of therapies to control allergy development in children.

Subsets of regulatory T cells and their roles in allergy

In recent years, it is recognized that acquired immunity is controlled by regulatory T cell (Treg). Since fundamental pathophysiological changes of allergy are mainly caused by hyperresponsiveness of immune system to allergens that acquires after birth, Tregs likely play key roles in the pathogenesis of allergy, particularly during the sensitization phase. However, accumulated information indicate that there are several distinctive subtypes of Tregs in man, and each of them seems to play different role in controlling immune system, which complicates the involvement of Tregs in allergy. The aim of the present study is to attempt to classify subtypes of Tregs and summarize their roles in allergy. Tregs should include natural Tregs (nTreg) including inducible costimulator (ICOS)(+) Tregs, inducible/adaptive Tregs (iTreg), interleukin (IL)-10-producing type 1 Tregs (Tr1 cells), CD8(+) Tregs and IL-17-producing Tregs. These cells share some common features including expression of Foxp3 (except for Tr1 cells), and secretion of inhibitory cytokine IL-10 and/or TGF-β. Furthermore, it is noticeable that Tregs likely contribute to allergic disorders such as dermatitis and airway inflammation, and play a crucial role in the treatment of allergy through their actions on suppression of effector T cells and inhibition of activation of mast cells and basophils. Modulation of functions of Tregs may provide a novel strategy to prevent and treat allergic diseases.

Intrauterine growth restriction and prematurity influence regulatory T cell development in newborns

PURPOSE

The aim of this study was to determine the relationship of birth weight and gestational age with regulatory T cells (Tregs) in cord blood of human newborns.

METHODS

Cord blood mononuclear cells (CBMCs) of 210 newborns were analyzed using flow cytometry to identify Tregs (CD3(+), CD4(+), CD25(high), FoxP3(high)) and measure FoxP3 mean fluorescence intensity (MFI). Suppressive index (SI) was calculated as FoxP3 MFI per Treg.

RESULTS

Mode of delivery had no significant effect on Tregs at birth. Term babies with growth restriction had fewer Tregs than their appropriate weight counterparts but equivalent SI. Preterm babies had higher percentages of Tregs, but lower SI than term controls. SI steadily increased through gestation.

CONCLUSIONS

Intrauterine growth restriction is correlated with fewer circulating Tregs and prematurity with decreased functionality of Tregs compared to term appropriate weight infants. This may have implications in diseases such as necrotizing enterocolitis that disproportionately affect premature and lower birth weight infants.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.

Gate-keeper function of the intestinal epithelium

There is currently a major focus on the role of the gut barrier function in balancing mucosal immune responses. Increased epithelial permeability for exogenous antigens is a crucial primary or secondary event in the pathogenesis of several disorders affecting body surfaces and beyond. The epithelial gate-keeper function is determined by the individual's age (e.g. preterm vs. term infant), diet, genetics, mucus composition, interactions between mast cells, nerves and neuropeptides, concurrent infection, the commensal microbiota and the epithelium-shielding effect of secretory IgA (SIgA) antibodies provided by breast milk or produced in the individual's gut. The integrity of the epithelial barrier furthermore depends on homeostatic regulatory mechanisms, including mucosal induction of regulatory T cells, where commensal microbiota-host interactions apparently play decisive roles. Thus, both extrinsic and intrinsic factors have been identified that may have an impact on the dynamics of the epithelial cell-cell junctions in the gut and thereby increase or reduce paracellular permeability. Experiments have shown that SIgA normally cooperates with innate defence factors to protect the epithelium and reinforce its barrier function. In the absence of SIgA commensal gut bacteria overstimulate innate epithelial immunity at the expense of expression of genes that regulate fat and carbohydrate metabolism, resulting in an epithelial gene signature that correlates with the development of lipid malabsorption. This shows that the intestinal epithelial barrier is a cross-road between defence and nutrition, and that SIgA is essential to keep the balance between these two functions.

Advances in mechanisms of allergy and clinical immunology in 2012

Manuscripts published in the "Mechanisms of allergy and clinical immunology" section of the Journal of Allergy and Clinical Immunology during 2012 enhanced our knowledge of the involvement of cytokines and other mediators in allergic disorders and described novel approaches for understanding mechanisms of allergic and immunologic diseases. Also published were articles focused on mechanisms of allergen-specific immunotherapy and the development of novel antiallergic treatments, as well as strategies to achieve tolerance to allergens. The highlights of these studies and their potential clinical implications are summarized in this review.

Impaired function of regulatory T cells in cord blood of children of allergic mothers

Allergy is one of the most common diseases with constantly increasing incidence. The identification of prognostic markers pointing to increased risk of allergy development is of importance. Cord blood represents a suitable source of cells for searching for such prognostic markers. In our previous work, we described the increased reactivity of cord blood cells of newborns of allergic mothers in comparison to newborns of healthy mothers, which raised the question of whether or not this was due to the impaired function of regulatory T cells (T(regs)) in high-risk children. Therefore, the proportion and functional properties of T(regs) in cord blood of children of healthy and allergic mothers were estimated by flow cytometry. The proportion of T(regs) [CD4(+)CD25(high)CD127(low) forkhead box protein 3 (FoxP3(+))] in cord blood of children of allergic mothers tends to be higher while, in contrast, the median of fluorescence intensity of FoxP3 was increased significantly in the healthy group. Intracellular presence of regulatory cytokines interleukin (IL)-10 and transforming growth factor (TGF)-beta was also higher in T(regs) of children of healthy mothers. Although we detected an increased proportion of T(regs) in cord blood of children of allergic mothers, the functional indicators (intracellular presence of regulatory cytokines IL-10 and TGF-beta, median of fluorescence intensity of FoxP3) of those T(regs) were lower in comparison to the healthy group. We can conclude that impaired function of T(regs) in cord blood of children of allergic mothers could be compensated partially by their increased number. Insufficient function of T(regs) could facilitate allergen sensitization in high-risk individuals after subsequent allergen encounter.

Workshop report from the National Institutes of Health Taskforce on the Research Needs of Eosinophil-Associated Diseases (TREAD)

BACKGROUND

Eosinophils are blood cells that are often found in high numbers in the tissues of allergic conditions and helminthic parasite infections. The pathophysiologic roles that eosinophils may serve in other human "eosinophil-associated" diseases remain obscure.

OBJECTIVE

National Institutes of Health (NIH) Institutes and the Office of Disease Prevention assembled an international taskforce of clinical and basic scientists with the charge to propose and prioritize unmet research needs in eosinophil-associated diseases.

METHODS

The taskforce used an organ system approach to identify the different and common themes of eosinophil cell involvement in these diseases. In early 2012, a draft document was circulated for review. The document was amended and the prioritizations were set at a NIH-organized workshop in June 2012.

RESULTS

The taskforce identified significant research needs. These needs cross disease entities but some are disease specific. There are substantial shortcomings to the various preclinical animal models, as well as significant gaps in our epidemiologic, pathophysiologic, diagnostic, prognostic, and therapeutic knowledge. The taskforce recognized that recent efforts by patient advocacy groups have played instrumental roles in improving the identification and characterization of these disorders. However, communications among the eosinophil-interested communities, for example, governmental funding and regulatory agencies, and industry and clinician scientists need to be more comprehensive.

CONCLUSIONS

Significant efforts are required to address our knowledge gaps to improve the outcomes of eosinophil-associated diseases. NIH Institutes, other federal agencies, lay organizations, and the pharmaceutical industry should consider the taskforce's recommendations in their future research activities.

IFN-λ and IgE-mediated allergic disease: a potential future role?

Reduced early microbial exposure has become a leading candidate to explain the rise in allergic disease, and research has focused on studying the interaction between the developing immune system and the microbial environment. However, despite intense interest, the pathways that lead to dysregulation of the immune system in allergic disease are still poorly understood. The newly described type III IFN-λ molecules were initially shown to exhibit antiviral activity, but these molecules are also likely to have an important role to play in the immune-epithelial interface, given their immunomodulatory functions and restricted receptor expression to immune and epithelial cells. Previous studies on the role of IFN-λ in allergic disease have been limited to allergic asthma. More recently, a genetic variation flanking IL28B encoding IFN-λ3 has been associated with allergic disease. Here, we examine this family and suggest how IFN-λ may be an important player in allergic disease.

Do Helicobacter pylori therapeutic vaccines need to be tailored to the age of the recipient?

Helicobacter pylori infections typically commence during childhood and last for life. Freire de Melo and colleagues compared cytokine profiles in the stomachs of H. pylori-infected and H. pylori-uninfected children and adults from Brazil. They suggest that the immune effector response in infected children differs from infected adults, specifically that stomachs of infected children contained elevated regulatory T-cell markers and less IL-17 compared with adults. As vaccine-mediated protection against H. pylori is believed to involve IL-17 and to be inhibited by regulatory T cells, this raises the possibility that individual H. pylorivaccines may have different efficacies in children and adults.

Serum and CSF soluble CD26 and CD30 concentrations in healthy pediatric surgical outpatients

Activated T-helper type 1 (Th1) lymphocytes induce a cellular type immune response, and Th2 lymphocytes, a humoral or antibody-mediated type immune response. Soluble CD26 (sCD26) and soluble CD30 (sCD30) are regarded as markers of Th1 and Th2 lymphocyte activation, respectively. Serum from 112 generally healthy pediatric surgical patients and cerebrospinal fluid (CSF) from 39, aged 1-17 years were measured for sCD26 and sCD30 using an enzyme-linked immunosorbent assay method. The detection limit for sCD26 was 6.8 ng/ml and for sCD30, 1.9 IU/ml. For serum sCD26 and sCD30, 2.5% and 97.5% percentiles constituted the reference limits, and the 95% credible intervals for the percentiles were calculated using regression models with a Bayesian approach. A significant between-gender difference was observed (P = 0.015) in serum sCD26 concentration, of which the lower limits ranged between 273 and 716 ng/ml for girls and 235 and 797 ng/ml for boys. The upper limits ranged between 1456 and 1898 ng/ml for girls and between 1419 and 1981 ng/ml for boys. Moreover, the concentrations of sCD26 increased in infants and children up to 10 years in girls and 12 years in boys. After this however, the values decreased. The serum sCD30 concentration was highest among the youngest infants aged 1 year (80-193 IU/ml), after which a consistent age-related decrease was found. The lowest values were found at the age of 17 years (10-89 IU/ml). A significant between-gender difference in sCD30 concentration was observed (P = 0.019). sCD26 and sCD30 concentrations were low in the CSF samples analyzed: 13.3 ng/ml (median); range 8.3-51.5 ng/ml and 7.6 IU/ml; 2.1-18.5 IU/ml, respectively. Reference limits for serum sCD26 in children aged 1-17 years were established as being 235-1800 ng/ml in toddlers and 400-1800 ng/ml in female adolescents and 700-2000 ng/ml in male adolescents. For sCD30; reference limits of 80-190 IU/ml were established in the youngest age group and 10-90 IU/ml in adolescents.