Prevention of adult asthma by early intervention during childhood: potential value of new generation immunomodulatory drugs

Accuracy of cough reporting by carers of Indigenous children

AIMS

The study aims to determine the reliability of a 24-h history of reported cough presence and quality (wet/dry) compared with objectively recorded cough, and evaluate factors that may influence cough reporting.

METHODS

A digital recorder (ICD-PX720, Sony, Tokyo, Japan) was attached to 47 Indigenous children for 24 h during admission at Royal Darwin Hospital. After recording, carers reported their child's cough details. Cough counts were objectively measured and details of cough reports by carer (cough present/absent, quality wet/dry, cough severity determined by visual analogue scale and verbal category descriptive score) were the main outcomes measured. Other factors examined were: carer's sex, age, education, smoking, carer's cough, parent versus non-parent, respiratory illness in child and mean parent-proxy cough-specific quality of life questionnaire. Data were entered into STATA (V.10, STATA Corp., College Station, TX, USA). Cohen's kappa (κ) coefficients and Spearman's rank correlation coefficient (rs ) were used for data analysis.

RESULTS

Reporting of cough by Indigenous carers (compared with cough monitoring) was slight when a low cough threshold (0.25 coughs/h) was used (κ = 0.17, 95% CI -0.15, 0.49) and moderate when a higher cough threshold was used (κ = 0.57, 95% CI 0.28, 0.88). Carers' evaluation of wet cough disagreed with clinician's evaluation (κ = -0.24, 95% CI -0.58, 0.09). Subjective reporting of cough severity moderately correlated with objective cough rates (rs = 0.41 to 0.44, 95% CI 0.11, 0.67). None of the factors examined was associated with reliability of cough reporting.

CONCLUSIONS

The unreliability of reporting of cough highlights the need for community education on the importance of cough to improve health-seeking behaviour for early detection and treatment of respiratory disease.

The paucity of ethical analysis in allergology

While a growing body of research is uncovering the aetiology and effective treatments for allergy, research that assess the broader ethical implications of this disease is lacking significantly. This article will demonstrate both the paucity of academic research concerning ethical implications in allergy and explain why ethical analysis is integral to formulating effective health strategies for allergic disease. An exhaustive literature search of publications in French and English identified less than 35 academic articles focussed on the topic of ethics and allergy; this is a miniscule number when compared to the amount of articles published on ethical issues related to other chronic illnesses, such as obesity. It is important to demonstrate to allergy specialists the need for, and utility of, further incorporating ethical analyses in allergology; the current success of Ethical, Legal, Social Implications (ELSI) research programmes in human genetics and nanotechnology will serve as notable examples. Indeed, future research and innovation in allergy will undoubtedly encounter ethical dilemmas and the allergology community should play a significant role in helping to address these issues. However, incorporating ethical analyses in allergology does not imply that the allergology community must acquire extensive knowledge in bioethics; instead, interdisciplinary research that incorporates expertise from allergology and bioethics would enable allergy specialists to advance critical knowledge development in this largely overlooked domain of study.

Lung dendritic cell developmental programming, environmental stimuli, and asthma in early periods of life

Dendritic cells (DCs) are important cells of our innate immune system. Their role is critical in inducing adaptive immunity, tolerance, or allergic response in peripheral organs—lung and skin. The lung DCs are not developed prenatally before birth. The DCs develop after birth presumably during the first year of life; exposures to any foreign antigen or infectious organisms during this period can significantly affect DC developmental programming and generation of distinct DC phenotypes and functions. These changes can have both short-term and long-term health effects which may be very relevant in childhood asthma and predisposition for a persistent response in adulthood. An understanding of DC development at molecular and cellular levels can help in protecting neonates and infants against problematic environmental exposures and developmental immunotoxicity. This knowledge can eventually help in designing novel pharmacological modulators to skew the DC characteristics and immune responses to benefit the host across a lifetime.

The predictive value of IgE as biomarker in asthma

BACKGROUND

The evidence for a causal relationship between allergens and asthma depends on epidemiologic findings showing a strong association between specific immunoglobulin E (IgE) antibodies or total IgE and asthma.

OBJECTIVE

To clarify the relationship between total serum IgE levels and asthma.

STUDY DESIGN

A cross-sectional study.

PATIENTS AND METHODS

A total of 562 asthmatic patients were included in the study, and their age range was from 17 to 52 years. The subjects included in the study were outpatients from the Asthma and Allergy Centre or Samara General Hospital outpatients Clinic. The diagnosis of asthma was performed by a specialist physician and was established according to the National Heart Blood and Lung Institute/World Health Organization (NHLBI/WHO) workshop on the Global Strategy for Asthma.

RESULTS

This study indicated that mean serum IgE level was 554 +/- 447 IU/mL in asthmatic patients, while that of the control population was 69 +/- 33 IU/mL. There was no overlap in the values of 95% confidence interval (CI) of higher control limit and lower asthmatic limit values. Addition of two standard deviations to the mean IgE value of the control group (134 IU/mL) does not overlap with the lower 95% CI of the asthmatic group. However, serum IgE was within normal values in 5.9% of asthmatic patients in our study population. There was an inverse correlation between serum IgE levels and forced expiratory volume in 1 second (FEV(1)) predicted percent for patients with asthma (r = -0.73, p < 0.0001). The predictive value of serum IgE in asthma was determined using Receiver Operating Characteristics (ROC) curve method. From the ROC curve, it can be seen that it is possible to get both high sensitivity and high specificity if the right cut-off value was chosen. In fact, a cut-off of 200 IU/mL would indicate sensitivity of 93% and specificity of 91% in this group of patients and control subjects. Following immunotherapy there was 36% reduction in total serum IgE level. The value of IgE was significantly reduced (p < 0.001) from 956 +/- 378 IU/mL at baseline to 613 +/- 194 IU/mL after treatment.

CONCLUSION

Serum IgE level was predictive in asthma, and it may be used to differentiate between asthmatic and non-asthmatic individuals in conjunction with other biomarkers. Specific immunotherapy reduced serum total IgE level in 36% of patients with asthma.

Postnatal cardiopulmonary adaptations to high altitude

Postnatal cardiopulmonary adaptations to high altitude constitute a key component of any set of responses developed to face high altitude hypoxia. Such responses are required ultimately to meet the energy demands necessary for adequate functioning at cell and organism level. After a brief insight on general and cardiopulmonary comparative studies in growing and adult organisms, differences and possible explanations for varying cardiopulmonary pathology, pulmonary artery hypertension, persistent right ventricular predominance and subacute high altitude pulmonary hypertension in different populations of children living at high altitude are discussed. Potential long-term implications of early chronic hypoxic exposure on later diseases are also presented. It is hoped that this review will help the practicing physician working at high altitude to make informed decisions concerning individual pediatric patients, specifically with regard to diagnosis and management of altitude-related cardiopulmonary pathology. Finally, plausibility and the knowledge-base of public health interventions to reduce the risks posed by suboptimal or inadequate postnatal cardiopulmonary responses to high altitude are discussed.

Effect and mechanism of lipopolysaccharide on allergen-induced interleukin-5 and eotaxins production by whole blood cultures of atopic asthmatics

Interleukin (IL)-5 and eotaxin families regulate the development of eosinophilic inflammation of asthma in a co-operative manner. The exposure to airborne lipopolysaccharide (LPS) induces varying degrees of airflow obstruction and neutrophilic airway inflammation. Production of IL-5 and eotaxin subfamily chemokines was analysed in response to Dermatophagoides pteronyssinus allergen (D.p.) according to the presence of specific IgE to D.p., and investigated the mechanism underlying their LPS-mediated regulation of these cytokines in response to the specific allergen. Peripheral blood cells (PBCs) from asthmatics with (group 1) or without (group 2) specific IgE to D.p. and from non-asthmatics with (group 3) or without (group 4) were stimulated with D.p. or LPS. For LPS-mediated inhibition of IL-5 and eotaxin-2 production, LPS-induced cytokines were added to the D.p.-stimulated PBCs. IL-5 and eotaxin-2, but not eotaxin-1 and 3, were significantly increased by D.p.-stimulated-PBCs from group 1, while only eotaxin-2 was elevated in group 3. Eotaxin-2 production was found in monocytes and correlated with the level of specific IgE to D.p. LPS treatment resulted in the decrease in eotaxin-2 and IL-5 production by the D.p.-stimulated PBCs. LPS-induced IL-10 completely inhibited D.p.-stimulated production of eotaxin-2 and IL-5. The differential responses of the eotaxin family to specific antigens suggest that the predominant role of eotaxin-2 and LPS may attenuate eosinophilic inflammation by inhibiting IL-5 and eotaxin-2 synthesis through IL-10 production.

Effects of early intervention with inhaled sodium cromoglycate in childhood asthma

International and Japanese guidelines classify childhood asthma as mild, moderate, or severe, and recommend treatment with "as needed" bronchodilators, inhaled sodium cromoglycate, and inhaled corticosteroids, respectively. Alternatively, some investigators proposed inhaled corticosteroids as first-line therapy to prevent airway inflammatory obstruction. This article describes a clinical study assessing the effect of early intervention with inhaled sodium cromoglycate in childhood asthma. This was a retrospective study of 189 asthmatic children treated with inhaled sodium cromoglycate for five years and whose age of onset of asthma was six year of age or younger. An end-of-study questionnaire completed the examination. Children administered oral or inhaled corticosteroids simultaneously with sodium cromoglycate, were excluded. Asthma scores as defined by the Japanese Pediatric Allergic Committee, were reduced continuously during the five years after the start of sodium cromoglycate treatment. The frequency of emergency department visits and hospitalizations also decreased. Significant between-period intervention differences showed improvement of clinical outcomes for children with severe asthma during the five years of sodium cromoglycate inhalation. The early intervention regime of starting sodium cromoglycate inhalation within two years of the onset of asthma shows a large improvement in the long-term prognosis of childhood asthma, especially for children with severe asthma. It is possible that starting inhaled sodium cromoglycate earlier than the present recommendation of corticosteroids could further improve clinical outcomes, but a prospective study should be performed to verify our results.

Density of dendritic cells in the human tracheal mucosa is age dependent and site specific

BACKGROUND

The mucosal immune system undergoes extensive changes in early childhood in response to environmental stimuli. Dendritic cells (DC) play a major role in the development of the immune system. However, few data exist on the influence of continuous environmental stimulation on the distribution and phenotype of human airway DC.

METHODS

Human tissue samples are mostly paraffin embedded which limits the use of several antibodies, and respiratory tissue for cryopreservation is difficult to obtain. Human frozen post mortem tracheal tissue was therefore used for this study. Only samples with epithelial adherence to the basement membrane were included (n = 34). Immunohistochemical staining and sequential overlay immunofluorescence were performed with DC-SIGN and a panel of leucocyte markers co-expressed by DC.

RESULTS

DC detected in the human tracheal mucosa using DC-SIGN correlated with the expression of HLA-DR, co-stimulatory and adhesion molecules. Higher cell densities were found at the ventral tracheal site of patients older than 1 year than in infants in the first year of life.

CONCLUSION

The increasing population of mucosal DC with age could reflect immunological maturation.

Ethical considerations in research involving children

Ethical concerns and medical advances unique to children and adolescents make pediatric research an evolving endeavor. The child's changing physiology from infancy to maturity requires understanding of the benefits and risks of medical therapies currently available, but often not tested in children, as well as the risks and benefits of inclusion of children in clinical research. Recent mandates from the US Food and Drug Administration (FDA) require that drugs be tested for safety and efficacy in children. Growing concern for the prevalence of chronic disorders and increasing understanding of distinct phenotypes of these disorders points to a likely need for unique interventions matched to specific phenotypes. All contribute to the increasing complexity of ethical considerations in pediatric research.

An immunoepidemiological approach to asthma: identification of in-vitro T-cell response patterns associated with different wheezing phenotypes in children

BACKGROUND

Increasing evidence suggests that patterns of T-cell immunity to inhalant allergens in genetically diverse human populations are more heterogeneous than previously assumed, and that covert differences in expression patterns might underlie variations in airway disease phenotypes. We tested this proposition in a community sample of children.

METHODS

We analysed data from 172 individuals who had been recruited antenatally to a longitudinal birth cohort study. Of the 194 birth cohort participants, data from the 147 probands (age range 8.6-13.5 years) who consented to blood collection were included along with data from 25 consenting siblings (mean age 11 years [range 7.4-17.4]). We ascertained clinical phenotypes related to asthma and allergy. We measured T-cell responses to allergens and mitogens, together with blood eosinophils and IgE/IgG antibodies, and assessed associations between these indices and clinical phenotypes.

FINDINGS

Atopy was associated with allergen-specific T-helper (Th)2 responses dominated by interleukin 4, interleukin 5, interleukin 9, interleukin 13, whereas interleukin 10, tumour necrosis factor alpha, and interferon gamma responses were common to both atopics and non-atopics. The wheal size from skin prick with allergen was positively associated with in-vitro interleukin 5 and interferon gamma responses, and negatively associated with interleukin 10. Asthma, especially in atopics, was strongly associated with eosinophilia/interleukin 5, and bronchial hyper-responsiveness (BHR) was associated with eosinophilia plus polyclonal interferon gamma production. BHR in non-atopics was associated with elevated allergen-specific and polyclonal interleukin 10 production.

INTERPRETATION

Parallel immunological and clinical profiling of children identified distinctive immune response patterns related to asthma and wheeze compared with BHR, in atopics non-atopics. Immunological hyper-responsiveness, including within the Th1 cytokine compartment, is identified as a hallmark of BHR.

RELEVANCE TO PRACTICE

These findings highlight the heterogeneity of immune response patterns in asthmatic children, including those with seemingly homogeneous Th2-driven atopic asthma. Further elucidation of the covert relationships between wheezing phenotypes and underlying immunophenotypes in this age group will potentially lead to more effective treatments for what is an unexpectedly heterogeneous collection of disease subtypes.

Anti-IgE therapy in allergic disease

PURPOSE OF REVIEW

Recombinant monoclonal humanized anti-IgE has put forward a fundamentally new concept for the control of allergic disorders. This review will present recent data from clinical studies with anti-IgE in asthma, allergic rhinitis, and food allergy and will examine the place of anti-IgE among current therapeutic options for the treatment of asthma.

RECENT FINDINGS

Therapy with anti-IgE depresses circulating free IgE to the limits of detection, inhibits early- and late-phase responses to allergens, suppresses inflammation and improves the control of allergic diseases. In moderate to severe asthma it results in fewer exacerbations and a lower requirement for both corticosteroids and beta-agonists. IgE appears to be an important regulator of high-affinity Fc receptors (FcepsilonRI) and, in the mouse, to enhance mast cell survival and activation. IgE receptors have been found on diverse inflammatory cells. Anti-IgE reduces the expression of FcepsilonRI on inflammatory cells. Current work has documented a marked decrease in tissue eosinophils, lymphocytes, and interleukin-4-positive cells by anti-IgE treatment and has provided insight into the mechanisms underlying improved control of asthma.

SUMMARY

Clinical studies with anti-IgE have promoted and will continue to advance the understanding of IgE-mediated disease mechanisms. They have documented its efficacy in the treatment of allergic diseases, but much remains to be learned about the most effective clinical strategies and the selection of patients for therapy.

Towards an integrated approach to lung health in adolescents in developing countries

The World Health Organization strategies, Integrated Management of Childhood Illness and Practical Approach to Lung health provide assessment and management guidelines for health workers in developing countries. We reviewed issues important to lung health in adolescents to highlight whether differences in factors such as adolescent behaviour have consequences for the development of case management guidelines, to form a bridge between guidelines for younger children and for adults and to make suggestions for further study. Pneumonia, asthma and tuberculosis are the leading lung health problems in adolescents. As countries industrialise, the importance of asthma mortality and morbidity increases as that of pneumonia and pulmonary tuberculosis decreases. Guidelines for managing pneumonia and asthma in children and adults in developing and developed countries should be adaptable for use in adolescents in developing countries, although more information is needed on predictors of severity such as respiratory rate cut-offs, level of fever, hypotension, malnutrition and level of consciousness. The effectiveness of low-cost treatment for asthma should be explored further. HIV and the global resurgence of tuberculosis pose significant challenges for improving adolescent lung health, and prevention of smoking initiation during adolescence is a priority goal of any integrated approach to improving lung health.

Drug development strategies for asthma: in search of a new paradigm

The spiraling costs of asthma treatment seem set to continue rising, given the equivocal performance of the latest generation of specific anti-inflammatory drugs in trials in adult asthmatics. We argue that the continuation of this trend is inevitable unless there is a substantial realignment of entrenched drug development policy in the pharmaceutical industry and a parallel shift in licensing policy by regulatory authorities to encourage the development of drugs capable of halting the progression from acute to chronic asthma when the disease first manifests in childhood. The theoretical framework for such an approach, including proof-of-principle data from studies in children with early-stage disease and a range of candidate drugs, already exists. What is needed is informed debate on the risks versus potential benefits of this approach.

Pilot study of the safety and effect of intranasal delipidated acid-treated Mycobacterium vaccae in adult asthma

OBJECTIVE

There is epidemiological and experimental evidence that exposure to mycobacteria has the potential to suppress the development of atopy and/or asthma. Delipidated, deglycolipidated and arabinogalactan-depleted autoclaved Mycobacterium vaccae (delipidated acid-treated M. vaccae) has been shown to suppress allergen-induced airway eosinophilia in mice.

METHODOLOGY

Thirty-seven adults with stable moderately severe asthma who were skin prick test-positive to house dust mite were randomized to receive two doses 2 weeks apart of delipidated acid-treated M. vaccae (first dose 0.4 mg and second dose 0.8 mg) or phosphate buffered saline, given as drops intranasally. Safety, tolerability and markers of asthma severity (including peak flow, FEV1, major and minor exacerbations, symptom scores and beta-agonist use), and nasal symptom scores, blood eosinophil and IgE levels were monitored for 8 weeks.

RESULTS

Delipidated acid-treated M. vaccae was safe and well tolerated although there was an occasional mild local reaction. There were no statistically significant differences between the treatment group and placebo for any of the outcome variables.

CONCLUSIONS

There is a requirement to elucidate the reasons why mycobacterial-based vaccines have not shown equivalent efficacy in human trials compared with animal models. The role of factors such as duration of disease, route of administration and the active component of mycobacteria need to be addressed.

Is there a role for treatment of asthma with omalizumab?

The allergic response is distinct from other immune reactions in its reliance on IgE, its high affinity receptor, Fc epsilon RI, and the primary effector cell--the tissue mast cell. Positive skin tests or raised concentrations of specific immunoglobulin E (IgE) in the serum define IgE sensitisation or "atopy". IgE participates both in immediate hypersensitivity response and in the induction of chronic allergic inflammation. It enhances allergen capture and Th2 cell activation, and may trigger other immunoregulatory pathways. Considerable effort in therapeutic research has focused on interference with IgE function because of its position high in the allergic cascade. Therapy with anti-IgE is one such approach that shows much promise.

Respiratory allergy: what are the uncertainties?

The prevalence of asthma is increasing worldwide. The increase has been found for both sexes, for all races and age groups. The factors responsible are unclear. The short period of increase makes it unlikely that a genetic change is responsible but rather suggests that either air pollutants or a behavioral change may be involved. Behavioral changes may include decreased exercise and outdoor activity due to, for example increased usage of television and computers. What is the role of allergy in the development of asthma? In allergic sensitization, allergens initiate the inflammation and IgE antibodies are typically present. Once asthma has developed, factors such as irritants, infections and exercise may result in acute symptomatology. Infancy is a high risk period for allergic sensitization since natural defense mechanisms are not fully developed. Epidemiologic evidence suggests that microbial stimuli during early childhood can influence induction of atopic diseases. In animal studies, pre-infection with respiratory virus has resulted in enhanced response to allergens. Another factor implicated in the surge of allergic disease is airborne particulates. Evidence has been obtained for an association of environmental tobacco smoke (ETS) with development of allergic sensitization. ETS enhances IgE production as does diesel and aluminum silicate, the latter a component of fly ash. What are the mechanisms responsible for the environmental influences on development of allergy? Th2 cytokine responses, with suppression of Th1 cytokines, are prominent in children. Th1 maturation appears to be promoted by microbial exposure. Increased understanding of the complex interactions of environmental factors with the developing immune system is essential to reverse the current upward trend in allergic respiratory disease.

Food allergy: what can be done to prevent progression to asthma?

OBJECTIVES

The primary objective of this review is to discuss risk factors for asthma development in food allergen-sensitized children. In the paper we discuss the possible measures to prevent progression to asthma by allergen and other adjuvant factor avoidance.

DATA SOURCES

A review from literature of articles on these topics was performed.

STUDY SELECTION

Relevant publications on asthma risk factors and implementation of protective factors were critically evaluated.

RESULTS

Children with familiar history of atopy and sensitization to food proteins in early infancy are at high risk of subsequent respiratory allergic diseases and require specific prevention. Because early allergic sensitization is a significant risk factor for later development of asthma, prevention of asthma by early allergen avoidance is mandatory in high-risk children. Adjuvant factors such as tobacco smoke and mold exposure may act as nonspecific triggers for the development of atopy. The role of protective factors such as infections in early life, breast-feeding, a "healthy" diet needs to be evaluated in prospective studies. Pharmacologic intervention with antihistamines led to significant reduction in incidence of asthma in high-risk children, but confirmatory longitudinal studies in large populations are necessary.

CONCLUSIONS

There is now accumulating evidence that preventing exposure to house-dust mite may significantly reduce the prevalence of childhood asthma. However, allergen avoidance can not be recommended as the only strategy. Avoidance of adjuvant factors and implementation of potential protective factors aimed to reduce the risk to progression to asthma need to be evaluated in prospective studies.

Influence of lipopolysaccharide exposure on airway function and allergic responses in developing mice

Exposure to endotoxin has been associated with an exacerbation of asthmatic responses in humans and animal models. However, recent evidence suggests that microbial exposure in early life may protect from the development of asthma and atopy. In this study, we sought to evaluate the effects of lipopolysaccaride (LPS) on airway function in developing mice. In addition, we evaluated the influence of LPS on subsequent allergen sensitization and challenge. Under light anesthesia, 2-3-week-old Balb/c mice received a single intranasal instillation of LPS or sterile physiologic saline. Measurements of airway function were obtained in unrestrained animals, using whole-body plethysmography. Airway responsiveness was expressed in terms of % enhanced pause (Penh) increase from baseline to aerosolized methacholine (Mch). In additional studies, we assessed the functional and cellular responses to ovalbumin sensitization and challenge following prior exposure to LPS. We found that exposure to LPS induced transient airway hyperresponsiveness to Mch. These functional changes were associated with the recruitment of neutrophils and lymphocytes into the bronchoalveolar lavage (BAL) fluid. Airway responsiveness after allergen sensitization and challenge was decreased by prior exposure to LPS. The analysis of BAL cells and cytokines (interferon-gamma and interleukin-4) did not reveal alterations in the overall Th1/Th2 balance. Our findings suggest that LPS leads to airway hyperresponsiveness in developing mice, and may protect against the development of allergen-driven airway dysfunction.

Life course health development: an integrated framework for developing health, policy, and research

The life course health development (LCHD) framework organizes research from several fields into a conceptual approach explaining how individual and population health develops and how developmental trajectories are determined by interactions between biological and environmental factors during the lifetime. This approach thus provides a construct for interpreting how people's experiences in the early years of life influence later health conditions and functional status. By focusing on the relationship between experiences and the biology of development, the LCHD framework offers a better understanding of how diseases occur. By suggesting new strategies for health measurement, service delivery, and research, as well as for improving health outcomes, this framework also supports health care-purchasing strategies to develop health throughout life and to build human health capital.

Viruses in asthma

Current evidence suggests that the overall load of infectious agents, including respiratory viruses, encountered early in life is an important factor influencing maturation of the immune system from a type 2 bias at birth towards predominantly type 1 responses, thus avoiding atopic diseases. The 'hygiene hypothesis' proposes that the relatively sterile environment present in industrialised Western countries has contributed to the recent epidemic of asthma and atopy. Whether specific infections are of greater or lesser protective value is an important question if strategies are to be derived to mimic the beneficial effects of childhood infection whilst avoiding morbidity and potential mortality of the natural pathogens. Infection by respiratory viruses is a major trigger of wheezing in infants and of exacerbations of asthma in older children. Viruses are detected in up to 85% of such episodes. Rhinovirus is common in all age groups; respiratory syncytial virus (RSV) is most important in infants and young children. Knowledge of the immunopathogenetic mechanisms of virus infection in the asthmatic airway will lead to the development of new treatments for virus-induced asthma.

Primary prevention of atopic asthma

Current recommendations given for primary prevention of allergic asthma often include advice on how to reduce exposure to inhalant allergens early in life. There is little support for such advice, however. On the contrary, recent studies indicate that extensive allergen exposure may actually reduce the likelihood of developing allergic asthma. However, recent studies indicate possible future venues for primary allergy prevention through immune modulation. This may possibly be achieved by stimulating the maturation of the immune system early in life by altering the microbial gut flora or by recently developed immunomodulatory Th2 antagonists. In the meantime, the avoidance of exposure to tobacco smoke remains the only recommendation that is reasonably well documented by evidence-based medicine, while allergen avoidance in primary prevention is not.

The dental patient with asthma. An update and oral health considerations

OVERVIEW

Asthma is a serious global health problem that has steadily increased in prevalence during the past two decades. New classification and treatment guidelines have been published, and dental providers need to be aware of these changes.

LITERATURE REVIEWED

The authors searched textbooks and MEDLINE, looking for the most updated medical information on asthma, as well as for previous publications on treatment of asthmatic patients in a dental setting.

RESULTS

More than 9,000 articles on asthma were published in English between 1997 and 2000. From 1960 until 2000, approximately 40 articles specifically addressed asthma and dental care. The authors reviewed more than 300 articles from the medical literature and all articles after 1980 that directly focused on oral health issues for importance and relevance.

CONCLUSIONS

Recent information regarding the etiology, pathogenesis and treatment of asthma had not been adequately addressed in the dental literature. Dental care of asthmatic patients may necessitate considerations beyond what has previously been published in the dental literature.

CLINICAL IMPLICATIONS

In the treatment of asthma, as with treatment of most medical conditions, oral health care providers play a role that is important in terms of both the patient's overall health and the systemic condition's effect on oral health. This article provides dentists with a timely update on asthma and the relationship between asthma and oral health, and it offers suggestions for safe and appropriate dental care.

Dendritic cells in the mucosa of the human trachea are not regularly found in the first year of life

BACKGROUND

Dendritic cells (DCs) in the mucosa of the respiratory tract might be involved in the early development of pulmonary allergy or tolerance. To date, little is known about when the first DCs occur in human airways.

METHODS

Specimens of the distal trachea from patients who had died from sudden death in the first year of life (n=29) and in older age groups (n=59) as well as from those who had died from respiratory tract infections in the first year of life (n=8) were examined by immunohistochemistry. Transmission electron microscopy was performed in additional samples from two adults.

RESULTS

In the sudden death subgroup DCs were absent in 76% of those who died in the first year of life but were present in 53 of the 59 older cases. All infants who had died of respiratory infectious diseases had DCs in the tracheal mucosa.

CONCLUSIONS

Mature DCs are not constitutively present in the human tracheobronchial mucosa in the first year of life, but their occurrence seems to be triggered by infectious stimuli. These data support the hypothesis that DCs play a crucial role in immunoregulation in early childhood.

Dendritic cells in the mucosa of the human trachea are not regularly found in the first year of life

BACKGROUND

Dendritic cells (DCs) in the mucosa of the respiratory tract might be involved in the early development of pulmonary allergy or tolerance. To date, little is known about when the first DCs occur in human airways.

METHODS

Specimens of the distal trachea from patients who had died from sudden death in the first year of life (n=29) and in older age groups (n=59) as well as from those who had died from respiratory tract infections in the first year of life (n=8) were examined by immunohistochemistry. Transmission electron microscopy was performed in additional samples from two adults.

RESULTS

In the sudden death subgroup DCs were absent in 76% of those who died in the first year of life but were present in 53 of the 59 older cases. All infants who had died of respiratory infectious diseases had DCs in the tracheal mucosa.

CONCLUSIONS

Mature DCs are not constitutively present in the human tracheobronchial mucosa in the first year of life, but their occurrence seems to be triggered by infectious stimuli. These data support the hypothesis that DCs play a crucial role in immunoregulation in early childhood.