Perennial Exposure Research Articles

Depiction of Major Mite Allergens in Severe Allergic Rhinitis with High Mite Perennial Exposure.

Airway diseases, including allergic rhinitis, are prompted by specific IgE antibodies against airborne allergens and notably those derived from mites. The presented study focused on the specific IgE immediate response to Dermatophagoides pteronyssinus (D. pteronyssinus) mite major allergens and the corresponding pertinence of molecular diagnosis in patients bothered with severe persistent rhinitis. Individuals exhibiting confirmed sensitization to D. pteronyssinus along with a clinical diagnosis of coexisting severe allergic rhinitis were included in the study. In vivo investigations encompassed intradermal testing with a battery of standardized allergenic extracts, concurrent with in vitro specific IgE to the crude extract of D. pteronyssinus, and associated individual molecular allergens were assessed. Fifty-five out of 59 subjects showed serodominant IgE responses to the major allergens Der p 1, Der p 2 and Der p 23. Both Der p 2 and Der p 23 reached a prevalence above 80%, while group 10 allergen tropomyosin was scarcely depicted (<10%) and exclusively present in younger individuals. The proposed component-resolved diagnosis panel accurately recognized 93.22% of D. pteronyssinus allergic patients. The raised seroprevalence of IgE response to Der p 23 also confirmed this constituent as a major D. pteronyssinus allergen in severe allergic rhinitis. A molecular approach appears to be essential to frame a more precise diagnosis and eventually a personalized immunotherapy regarding this allergic condition.

Hygienic conditions influence sensitization to Blomia tropicalis allergenic components: Results from the FRAAT birth cohort.

In tropical zones, perennial exposure to house dust mite (HDM) allergens and helminth infections is present. Studying the impact of these conditions on the inception and evolution of allergic diseases is necessary to have an accurate view of their natural history. We aimed to evaluate the dynamics of genuine sensitization to Blomia tropicalis and Ascaris in children from the FRAAT birth cohort and the effects of helminth infection, environmental HDM allergen levels, and sociodemographic factors. Children were followed up to 6years old. Specific IgE to recombinant allergens from B.tropicalis (Blo t 5 and Blo t 12) and Ascaris spp (Asc l 3, Asc l 13 and Asc s 1) was measured by ELISA at different time points. Allergen levels were measured in dust when children were 6months old. IgE sensitization increased over time up to 3years old. Correlation among the specific IgE levels to B.tropicalis and Ascaris components is poor at year 1, but coefficients are high and significant (Spearman's rho coefficients >0.70) at year 6. Unhygienic conditions increased the odds of sensitization to B.tropicalis allergenic components. Blo t 5 levels were lower in the poorest. IgE response to Blo t 5 and Blo t 12 was less intense in children with high exposure to Blo t 5 (levels >80th percentile). In this tropical community, the pattern of childhood IgE sensitization is different from that in developing countries and is influenced by the hygienic conditions.

Particular characteristics of atopic eczema in tropical environments. The Tropical Environment Control for Chronic Eczema and Molecular Assessment (TECCEMA) cohort study.

BackgroundAtopic dermatitis is a prevalent health problem in the world. Allergic sensitization is an important risk factor, but the roles of other factors, inherent in tropic region, are unknown.ObjectiveA cohort study was designed in a tropical city to investigate molecular and environmental risk factors for eczema, considering as particular features perennial exposure to mites, poor living conditions and others tropical characteristics.Methods433 patients were included at baseline and biological samples were collected during 24 months of follow-up. Clinical information was collected using questionnaires (SCORAD, DLQI and a subjective scale) during each clinical assessment.ResultsThe prevalence of atopic eczema was 93%, with similar frequency between children and adults; parents history of eczema and polysensitization to mites, dogs, cats, cockroaches and birds, were risk factors for severe and persistent eczema and allergic comorbidities. Food sensitization was present in 16% of patients but food-induced allergies were scarce. Psychiatric, dental and ocular disorders were the most frequent non-allergic comorbidities.Study limitationsselection bias.ConclusionWe presented a tropical cohort of patients with eczema and we identified some risk factors for severe and persistent dermatitis. Some patterns of sensitization were associated with severe eczema and respiratory symptoms, and the natural history of "atopic march" is different to that described in some industrialized countries. The collection of biological samples will contribute to the understanding of the gene/environment interactions leading to allergy inception and evolution.

Our ailing profession: we need more than resilience and replenishment

The malaise among NHS healthcare workers is akin to a patient dying from an internal haemorrhage: oral replenishments, or even transfusions, may be very inadequate. A recent day conference parried this perspective. The conference was designed to ventilate and motivate our dispirited and defecting doctors. Its brief title was businesslike in its optimism: Restoring Health in the NHS. Recruitment was geared towards the young: the growing loss of their ranks is causing increasing concern for, first, abandoned colleagues and, then, health planners and government. In the morning about a hundred of us sat together. A young and cheery consultant, Dr Y, outlined the now familiar litany of unavoidable stresses for doctors: increased expectations from ‘consumers’, ‘providers’, and commissioners amidst unyielding, or declining, resources; increasingly complex, technical multitasking amidst ever-present, often opaque, human complexity; the frequent anxiety from inevitable yet serious fallibility; our often foolishly litigious culture; perennial exposure to pain, loss, decline, and handicap; long and antisocial hours; the eventual damage to our intimate relationships. But Dr Y was upbeat: we could prepare and brace ourselves for these ordeals, tend to our resilience. Anchoring her suggestions in Selye’s classic research into the physiology of stress,1 she offered sensible, restorative, and reparative advice on our needs for eating, sleeping, breathing, exercising, emoting, laughing, loving, and meditating. She ended …

Particular characteristics of allergic symptoms in tropical environments: follow up to 24 months in the FRAAT birth cohort study

BackgroundEarly wheezing and asthma are relevant health problems in the tropics. Mite sensitization is an important risk factor, but the roles of others, inherent in poverty, are unknown. We designed a birth-cohort study in Cartagena (Colombia) to investigate genetic and environmental risk factors for asthma and atopy, considering as particular features perennial exposure to mites, parasite infections and poor living conditions.MethodsPregnant women representative of the low-income suburbs of the city were randomly screened for eligibility at delivery; 326 mother-infant pairs were included at baseline and biological samples were collected from birth to 24 months for immunological testing, molecular genetics and gene expression analysis. Pre and post-natal information was collected using questionnaires.Results94% of families were from the poorest communes of the city, 40% lacked sewage and 11% tap-water. Intestinal parasites were found as early as 3 months; by the second year, 37.9% of children have had parasites and 5.22% detectable eggs of Ascaris lumbricoides in stools (Median 3458 epg, IQR 975-9256). The prevalence of "wheezing ever" was 17.5% at 6 months, 31.1% at 12 months and 38.3% at 24 months; and recurrent wheezing (3 or more episodes) 7.1% at 12 months and 14.2% at 24 months. Maternal rhinitis [aOR 3.03 (95%CI 1.60-5.74), p = 0.001] and male gender [aOR 2.09 (95%CI 1.09 - 4.01), p = 0.026], increased risk for wheezing at 6 months. At 24 months, maternal asthma was the main predisposing factor for wheezing [aOR 3.65 (95%CI 1.23-10.8), p = 0.01]. Clinical symptoms of milk/egg allergy or other food-induced allergies were scarce (1.8%) and no case of atopic eczema was observed.ConclusionsWheezing is the most frequent phenotype during the first 24 months of life and is strongly associated with maternal asthma. At 24 months, the natural history of allergic symptoms is different to the "atopic march" described in some industrialized countries. This cohort is representative of socially deprived urban areas of underdeveloped tropical countries. The collection of biological samples, data on exposure and defined phenotypes, will contribute to understand the gene/environment interactions leading to allergy inception and evolution.

Differential Patterns of Infection and Disease with P. falciparum and P. vivax in Young Papua New Guinean Children

BackgroundWhere P. vivax and P. falciparum occur in the same population, the peak burden of P. vivax infection and illness is often concentrated in younger age groups. Experiences from malaria therapy patients indicate that immunity is acquired faster to P. vivax than to P. falciparum challenge. There is however little prospective data on the comparative risk of infection and disease from both species in young children living in co-endemic areas.Methodology/Principal FindingsA cohort of 264 Papua New Guinean children aged 1-3 years (at enrolment) were actively followed-up for Plasmodium infection and febrile illness for 16 months. Infection status was determined by light microscopy and PCR every 8 weeks and at each febrile episode. A generalised estimating equation (GEE) approach was used to analyse both prevalence of infection and incidence of clinical episodes. A more pronounced rise in prevalence of P. falciparum compared to P. vivax infection was evident with increasing age. Although the overall incidence of clinical episodes was comparable (P. falciparum: 2.56, P. vivax 2.46 episodes / child / yr), P. falciparum and P. vivax infectious episodes showed strong but opposing age trends: P. falciparum incidence increased until the age of 30 months with little change thereafter, but incidence of P. vivax decreased significantly with age throughout the entire age range. For P. falciparum, both prevalence and incidence of P. falciparum showed marked seasonality, whereas only P. vivax incidence but not prevalence decreased in the dry season.Conclusions/SignificanceUnder high, perennial exposure, children in PNG begin acquiring significant clinical immunity, characterized by an increasing ability to control parasite densities below the pyrogenic threshold to P. vivax, but not to P. falciparum, in the 2nd and 3rd year of life. The ability to relapse from long-lasting liver-stages restricts the seasonal variation in prevalence of P. vivax infections.

Sapflow and water use of freshwater wetland trees exposed to saltwater incursion in a tidally influenced South Carolina watershed

Sea-level rise and anthropogenic activity promote salinity incursion into many tidal freshwater forested wetlands. Interestingly, individual trees can persist for decades after salt impact. To understand why, we documented sapflow (Js), reduction in Jswith sapwood depth, and water use (F) of baldcypress ( Taxodium distichum (L.) Rich.) trees undergoing exposure to salinity. The mean Jsof individual trees was reduced by 2.8 g H2O·m–2·s–1(or by 18%) in the outer sapwood on a saline site versus a freshwater site; however, the smallest trees, present only on the saline site, also registered the lowest Js. Hence, tree size significantly influenced the overall site effect on Js. Trees undergoing perennial exposure to salt used greater relative amounts of water in outer sapwood than in inner sapwood depths, which identifies a potentially different strategy for baldcypress trees coping with saline site conditions over decades. Overall, individual trees used 100 kg H2O·day–1on a site that remained relatively fresh versus 23.9 kg H2O·day–1on the saline site. We surmise that perennial salinization of coastal freshwater forests forces shifts in individual-tree osmotic balance and water-use strategy to extend survival time on suboptimal sites, which further influences growth and morphology.

Today’s allergic rhinitis patients are different: new factors that may play a role

Most of today's patients suffering from allergic rhinitis (AR) are sensitized to more than one trigger and suffer from persistent and moderate/severe symptoms, which severely impair their quality of life (QOL). The objective of this article was to review the data on the effect of increased air pollution, changes in indoor environment/lifestyle/affluence, exposure to new allergens and psychologically stressful lifestyles, as also to explore their potential in the development of this more 'aggressive' form of disease. Increased fossil fuel-generated air pollution may increase the risk of allergic sensitization, airway responsiveness to allergens, and allergenicity and the bioavailability of airborne allergens. Changes in indoor environment/lifestyle/affluence appear to have led to more time being spent indoors and resulted in perennial exposure to indoor allergens, changes in sensitization patterns, and polysensitization to a variety of novel cross-reacting exotic food and pet allergens. Although evidence suggests an association between psychological stress and increased risk for atopy and allergic disease, further studies are required to demonstrate this unequivocally. The more persistent and moderate/severe nature of the disease suggests a need for modification of current treatment strategies and advocacy of the use from the outset of agents, which are both efficacious and safe in managing severe and persistent AR symptoms and in improving the QOL of affected individuals.

Peripheral blood mononuclear cell proliferative responses in the first year of life in babies born to allergic parents

Raised peripheral blood mononuclear cells (PBMCs) proliferative responses to food allergens have been demonstrated in children with established atopic dermatitis. In this report we investigate the PBMC proliferative responses to inhalant and food allergens from babies at birth, 6 months and 1 year of age, born to atopic and non-atopic parents. PBMCs, separated by density gradient centrifugation, were cultured for 6 days with autologous plasma and a range of allergens (house dust mite [HDM], cat, grass pollen, tree pollen, betalactoglobulin and ovalbumin). Proliferative responses were measured by the uptake of [3H] thymidine added for the final 18 h of culture. At birth, infants born to atopic parents who developed allergic disease by 1 year of age had significantly more positive responses (stimulation index > or = 2 with a value of > or = 1000 cpm above background) to HDM (P = 0.0097), betalactoglobulin (P = 0.0166) and ovalbumin (P = 0.0035) than newborns who did not develop allergy. Infants who developed allergy also had significantly more positive responses to HDM (P = 0.03) and ovalbumin (P = 0.0057) than babies, born to non-atopic parents, who did not develop allergies. At 6 months of age a significant fall in response to HDM (P = 0.003) and cat fur extract (P = 0.006) was seen in infants who developed allergic disease by 1 year of age. A similar pattern was seen for proliferative responses to betalactoglobulin and ovalbumin (P = 0.0006, P = 0.004). Conversely, proliferations to grass and tree pollen extracts increased at 6 months (P = 0.04, P = NS) and 1 year (P = NS, P = 0.01) compared with birth which was significant for infants who did not develop allergic disease. Proliferative responses to seasonal allergens increased over the first year of life whilst those to perennial allergens, both inhalant and food, fell. This suggests either the induction of a systemic immune tolerance by perennial exposure to antigens or movement of sensitized cells to target organs where allergen exposure occurs. This process may be independent of the development allergic disease.