Major Allergen Content in Allergen Immunotherapy Products: The Limited Value of Numbers.

The prevalence of allergic disorders has increased drastically over the last 50 years to the extent that they can be considered epidemic. At present, allergen-specific immunotherapy (AIT) is the only therapy that targets the underlying cause of allergic disorders, and evidence of its superiority is based on data accumulated from clinical trials and observational studies demonstrating efficacy and safety. However, several aspects remain unresolved, such as harmonization and standardization of manufacturing and quantification procedures across manufacturers, homogeneous reporting of strength, and the establishment of international reference standards for many allergens. This article discusses issues related to the measurement of major allergen content in AIT extracts, raising the question of whether comparison of products from different manufacturers is an appropriate basis for selecting a specific AIT product. Allergen standardization in immunotherapy products is critical for ensuring quality and, thereby, safety and efficacy. However, lack of harmonization in manufacturing processes, allergen quantification (methodologies and references), national regulatory differences, clinical practice, and labeling shows that the comparison of AIT products based solely on major allergen amounts is not rational and, in fact, impossible. Moreover, when rating the information given for a specific product, it is necessary to take into account further inherent characteristics of products and their application in clinical practice, such as the state of extract modification, addition of adjuvant or adjuvant system, route of administration (sublingual/ subcutaneous), and cumulative dose as per posology (including the volume per administration). Finally, only convincing clinical data can serve as the basis for product-specific evaluation and cross-product comparability of individual products.

Pregnancy and perinatal conditions and atopic disease prevalence in childhood and adulthood.

BACKGROUND: Previous studies showed controversial results for the influence of pregnancy-related and perinatal factors on subsequent respiratory and atopic diseases in children. The aim of this study was to assess the association between perinatal variables and the prevalence of asthma, bronchial hyperreactivity (BHR), flexural eczema (FE), allergic rhinitis, and sensitization in childhood and early adulthood. METHODS: The studied population was first examined in Munich and Dresden in 1995/1996 at age 9-11 years. Participants were followed until age 19-24 years using questionnaires and clinical examinations. Associations between perinatal data and subsequent atopic diseases were examined using logistic regression analyses adjusting for potential confounders. RESULTS: Cesarean section was statistically significantly associated with BHR in early adulthood (odds ratio 4.8 [95% confidence interval 1.5-15.2]), while assisted birth was associated with presence of asthma symptoms in childhood (2.2 [1.2-3.9]), FE symptoms (2.2 [1.2-4.3]) and doctor's diagnosis of atopic dermatitis (1.9 [1.0-3.4]) in childhood, and sensitization in early adulthood (2.2 [1.1-4.3]). Lower birth length (1.9 [1.1-3.2]), lower birthweight (0.5 [0.3-0.9]), and higher birthweight (0.6 [0.4-1.0]) were predictive of sensitization in early adulthood compared to average birth length and birthweight, respectively. None of the other perinatal factors showed statistically significant associations with the outcomes. CONCLUSIONS: Our results indicate that children who are born by cesarean section and especially by assisted birth, might be at greater risk for developing asthma, FE, and sensitization and should hence be monitored. Prenatal maternal stress might partly explain these associations, which should be further investigated.

[Cannabis--Position Paper of the German Respiratory Society (DGP)]. / Cannabis--Positionspapier der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin e.V. (DGP).

In this position paper, the adverse health effects of cannabis are reviewed based on the existing scientific literature; in addition possible symptom-relieving effects on some diseases are depicted. In Germany, cannabis is the most widely used illicit drug. Approximately 600,000 adult persons show abusive or addictive cannabis consumption. In 12 to 17 year old adolescents, cannabis use increased from 2011 to 2014 from 2.8 to 6.4%, and the frequency of regular use from 0.2 to 1.5%. Currently, handling of cannabinoids is much debated in politics as well as in general public. Health aspects have to be incorporated into this debate. Besides analysing mental and neurological side effects, this position paper will mainly focus on the influences on the bronchopulmonary and cardiovascular system. There is strong evidence for the induction of chronic bronchitis. Allergic reactions including asthma are known, too. Associations with other diseases like pulmonary emphysema, lung cancer and pneumonia are not sufficiently proven, however cannot be excluded either. In connection with the use of cannabis cardiovascular events such as coronary syndromes, peripheral vascular diseases and cerebral complications have been noted. Often, the evidence is insufficient due to various reasons; most notably, the overlapping effects of tobacco and cannabis use can frequently not be separated adequately. Empirically, early beginning, high-dosed, long-lasting and regular cannabis consumption increase the risk of various psychological and physical impairments and negatively affect age-based development. Concerns therefore relate especially to children and adolescents. There is only little scientific evidence for medical benefits through cannabis as a remedy; systematic research of good quality, in particular prospective, randomised, placebo-controlled double-blinded studies are rare. The medical societies signing this position paper conclude that cannabis consumption is linked to adverse health effects which have to be taken into consideration in the debate about the social attitude towards cannabinoids. The societies agree that many aspects regarding health effects of cannabis are still uncertain and need clarification, preferably through research provided by controlled studies.

Childhood asthma is associated with mutations and gene expression differences of ORMDL genes that can interact.

BACKGROUND: Genomewide association studies identified ORMDL3 as a plausible asthma candidate gene. ORMDL proteins regulate sphingolipid metabolism and ceramide homeostasis and participate in lymphocyte activation and eosinophil recruitment. Strong sequence homology between the three ORMDL genes and ORMDL protein conservation among different species suggest that they may have shared functions. We hypothesized that if single nucleotide polymorphisms (SNPs) in ORMDL3 alter its gene expression and play a role in asthma, variants in ORMDL1 and ORMDL2 might also be associated with asthma. METHODS: Asthma associations of 44 genotyped SNPs were determined in at least 1303 subjects (651 asthmatics). ORMDL expression was evaluated in peripheral blood mononuclear cells (PBMC) from 55 subjects (eight asthmatics) before and after allergen stimulation, and in blood (n = 60, 5 asthmatics). Allele-specific cis-effects on ORMDL expression were assessed. Interactions between human ORMDL proteins were determined in living cells. RESULTS: Sixteen SNPs in all three ORMDLs were associated with asthma (14 in ORMDL3). Baseline expression of ORMDL1 (P = 1.7 × 10(-6) ) and ORMDL2 (P = 4.9 × 10(-5) ) was significantly higher in PBMC from asthmatics, while induction of ORMDLs upon stimulation was stronger in nonasthmatics. Disease-associated alleles (rs8079416, rs4795405, rs3902920) alter ORMDL3 expression. ORMDL proteins formed homo- and heterooligomers and displayed similar patterns of interaction with SERCA2 and SPT1. CONCLUSIONS: Polymorphisms in ORMDL genes are associated with asthma. Asthmatics exhibit increased ORMDL levels, suggesting that ORMDLs contribute to asthma. Formation of heterooligomers and similar interaction patterns with proteins involved in calcium homeostasis and sphingolipid metabolism could indicate shared biological roles of ORMDLs, influencing airway remodeling and hyperresponsiveness.

A role of FCER1A and FCER2 polymorphisms in IgE regulation.

BACKGROUND: Both FCER2 and FCER1A encode subunits of IgE receptors. Variants in FCER1A were previously identified as major determinants of IgE levels in genome-wide association studies. METHODS: Here we investigated in detail whether FCER2 polymorphisms affect IgE levels alone and/or by interaction with FCER1A polymorphisms. To cover the genetic information of FCER2, 21 single-nucleotide polymorphisms (SNPs) were genotyped by Illumina HumanHap300 BeadChip (5 SNPs) and the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; 14 SNPs) in at least 1303 Caucasian children (651 asthmatics) (ISAAC II/ MAGICS population); genotypes of two SNPs were imputed. RESULTS: SNP rs3760687 showed the most consistent effect on total serum IgE levels (b [SE] = -0.38 [0.16]; P = 0.016), while FCER2 polymorphisms in general were predominantly associated with mildly-to-moderately increased IgE levels (50th and 66th percentiles). Gene-by-gene interaction analysis suggests that FCER2 polymorphism rs3760687 influences IgE levels mainly in individuals not homozygous for the risk allele of FCER1A polymorphism rs2427837, which belongs to the major IgE-determining tagging bin in the population. CONCLUSION: FCER2 polymorphism rs3760687 affects moderately elevated total serum IgE levels, especially in the absence of homozygosity for the risk allele of FCER1A SNP rs2427837.

Fine-mapping of IgE-associated loci 1q23, 5q31, and 12q13 using 1000 Genomes Project data.

BACKGROUND: Genome-wide association studies (GWAS) repeatedly identified 1q23 (FCER1A), 5q31 (RAD50-IL13 and IL4), and 12q13 (STAT6) as major susceptibility loci influencing the regulation of total serum IgE levels. As GWAS may be insufficient to capture causal variants, we performed fine-mapping and re-genotyping of the three loci using 1000 Genomes Project datasets. METHODS: Linkage disequilibrium tagging polymorphisms and polymorphisms of putative functional relevance were genotyped by chip technology (24 polymorphisms) or MALDI-TOF-MS (40 polymorphisms) in at least 1303 German children (651 asthmatics). The effect of polymorphisms on total serum IgE, IgE percentiles, and atopic diseases was assessed, and a risk score model was applied for gene-by-gene interaction analyses. Functional effects of putative causal variants from these three loci were studied in silico. RESULTS: Associations from GWAS were confirmed and extended. For 1q23 and 5q31, the majority of associations were found with mild to moderately elevated IgE levels, while in the 12q13 locus, single-nucleotide polymorphisms (SNPs) were associated with strongly elevated IgE levels. Gene-by-gene interaction analyses suggested that the presence of mutations in all three loci increases the risk for elevated IgE up to fourfold. CONCLUSION: This fine-mapping study confirmed previous associations and identified novel associations of SNPs in 1q23, 5q31, and 12q13 with different levels of serum IgE and their concomitant contribution to IgE regulation.

Polymorphisms in the IRF-4 gene, asthma and recurrent bronchitis in children.

BACKGROUND: Interferon-regulatory factors (IRFs) play a crucial role in immunity, not only influencing interferon expression but also T cell differentiation. IRF-4 was only recently recognized as a further major player in T cell differentiation. OBJECTIVE: As IRF-1 polymorphisms were shown to be associated with atopy and allergy, we comprehensively investigated effects of IRF-4 variants on allergy, asthma and related phenotypes in German children. METHODS: Fifteen tagging single nucleotide polymorphisms (SNPs) in the IRF-4 gene were genotyped by MALDI-TOF MS in the cross-sectional ISAAC phase II study population from Munich and Dresden (age 9-11; N = 3099). Replication was performed in our previously established genome-wide association study (GWAS) data set (N = 1303) consisting of asthma cases from the Multicenter Asthma Genetic in Childhood (MAGIC) study and reference children from the ISAAC II study. RESULTS: SNPs were not significantly associated with asthma but with bronchial hyperresponsiveness, atopy and, most interestingly, with recurrent bronchitis in the first data set. The IRF-4 variant rs9378805 was associated with recurrent bronchitis in the ISAAC population and replicated in the GWAS data set where further SNPs showed associations with recurrent bronchitis and asthma. CONCLUSIONS: We found genetic associations in IRF-4 to be associated with recurrent bronchitis in our two study populations. Associated polymorphisms are localized in a putative regulatory element in the 3'UTR region of IRF-4. These findings suggest a putative role of IRF-4 in the development of bronchitis.

Rare TLR2 mutations reduce TLR2 receptor function and can increase atopy risk.

BACKGROUND: Common genetic variations in toll-like receptor 2 (TLR2), an innate pathogen recognition receptor, may influence the development of atopic diseases. So far, very little is known about the role of rare TLR2 mutations in these diseases. OBJECTIVE: We investigated the functional properties of six rare amino acid changes in TLR2 (and one amino acid change in a TLR2 pseudogene) and studied their effect on atopic sensitization and disease. METHODS: We identified rare TLR2 mutations leading to amino acid changes from databases. Functional effects of TLR2 variants were analyzed by NF-kappaB-dependent luciferase reporter assay and interleukin-8 enzyme linked immunosorbent assay in vitro. The frequency of these mutations was determined in a random sample of the general population (n = 368). Association with atopic diseases were studied in a cross sectional German study population (n = 3099). RESULTS: Three out of six mutations in the TLR2 gene altered receptor activity in vitro. Out of these, only the minor allele of R753Q occurred reasonably frequent in the German population (minor allele frequency 3%). The risk to develop atopy increased by 50% in carriers of the 753Q allele (P = 0.021) and total (P = 0.040) as well as allergen specific serum IgE levels (P = 0.011) were significantly elevated. CONCLUSION: The rare but functionally relevant mutation R753Q in TLR2 may significantly affect common conditions such as atopic sensitization in the general population.

Major Allergen Content in Allergen Immunotherapy Products: The Limited Value of Numbers

The prevalence of allergic disorders has increased drastically over the last 50 years to the extent that they can be considered epidemic.At present, allergen-specific immunotherapy (AIT) is the only therapy that targets the underlying cause of allergic disorders, and evidenceof its superiority is based on data accumulated from clinical trials and observational studies demonstrating efficacy and safety. However,several aspects remain unresolved, such as harmonization and standardization of manufacturing and quantification procedures acrossmanufacturers, homogeneous reporting of strength, and the establishment of international reference standards for many allergens. Thisarticle discusses issues related to the measurement of major allergen content in AIT extracts, raising the question of whether comparison ofproducts from different manufacturers is an appropriate basis for selecting a specific AIT product. Allergen standardization in immunotherapyproducts is critical for ensuring quality and, thereby, safety and efficacy. However, lack of harmonization in manufacturing processes,allergen quantification (methodologies and references), national regulatory differences, clinical practice, and labeling shows that thecomparison of AIT products based solely on major allergen amounts is not rational and, in fact, impossible. Moreover, when rating theinformation given for a specific product, it is necessary to take into account further inherent characteristics of products and their applicationin clinical practice, such as the state of extract modification, addition of adjuvant or adjuvant system, route of administration (sublingual/subcutaneous), and cumulative dose as per posology (including the volume per administration). Finally, only convincing clinical data canserve as the basis for product-specific evaluation and cross-product comparability of individual products. (AU)

La prevalencia de las enfermedades alérgicas se ha incrementado drásticamente en los últimos 50 años y hoy pueden considerarse unaepidemia. Actualmente, la inmunoterapia específica con alérgenos (ITA) es el único tratamiento dirigido a la causa subyacente de lasenfermedades alérgicas y su superioridad se basa en resultados de ensayos clínicos/estudios observacionales que demuestran su eficaciay seguridad. Pero quedan aspectos sin resolver, como la armonización y estandarización de los procesos de fabricación y cuantificaciónentre fabricantes, la declaración homogénea de la potencia y el establecimiento de estándares internacionales de referencia. En este artículo se discuten aspectos relacionados con la medida del contenido de alérgenos mayores en los extractos de ITA, cuestionandosi, como base para elegir entre productos, es apropiada la comparación entre diferentes fabricantes. La estandarización alergénica escrucial para asegurar la calidad y, por tanto, la seguridad y eficacia de la ITA. Sin embargo, la falta de armonización en los procesos defabricación, la cuantificación alergénica, las diferencias regulatorias, la práctica clínica y el etiquetado, demuestran que comparar productosbasándose únicamente en la cantidad de alérgeno mayor no está justificado y es imposible. Además, cuando se evalúa la informaciónpara un determinado producto, deben tenerse en cuenta las características propias de cada producto y su uso clínico, como el estado dela modificación del extracto, la adición de adyuvantes, la vía de administración y la dosis acumulada. Solo datos clínicos convincentesdeben servir para la evaluación específica de cada producto o como base para la comparación entre productos. (AU)

Exhaled breath analysis in childhood rheumatic disorders--a longitudinal study.

We aimed to evaluate the fraction of exhaled nitric oxide (FENO50) and deaerated exhaled breath condensate pH (dEBCpH) as non-invasive markers of subclinical airway inflammation in pediatric patients with rheumatologic disorders. We determined FENO50 and dEBCpH in a prospective study spanning at least 12 months, comprising 85 pediatric patients with rheumatologic disorders, including juvenile idiopathic arthritis (JIA, n = 63), chronic recurrent multifocal osteomyelitis (CRMO, n = 6), systemic lupus erythematosus (SLE, n = 3), juvenile dermatomyositis (JDM, n = 1) and other rheumatic disorders (n = 12). dEBCpH was determined once in a group of children without evidence of rheumatologic or pulmonary disease (controls, n = 90). Findings were correlated with results of pulmonary function tests. Atopic sensitization was assessed by RAST or skin prick test in 76 patients. Atopic sensitization was detected in 34% (26/76) of patients. Neither FENO50 nor dEBCpH correlated with disease activity, but intermediately (20-35 ppb) or highly elevated (>35 ppb) levels were observed at least once in 26 patients (31%), 19 of whom had atopic sensitization. Median dEBCpH did not differ between cases and controls (8.05 versus 8.02; p = 0.48). Median dEBCpH decreased slightly over the study period (p = 0.02), whereas FENO50 values did not change significantly (p = 0.89). There were several patients with significantly abnormal dEBCpH values that could not be readily explained by diagnosis, higher disease activity, medications, or atopic sensitization. Thus, there were no consistent abnormalities in FENO50 or dEBCpH in this cohort of Caucasian patients with relatively stable rheumatologic disorders, but there were some patients with abnormal values of unknown significance.

Clinical evaluation of the peak inspiratory flow generated by asthmatic children through the Novolizer.

STUDY OBJECTIVE: To assess whether asthmatic children may generate sufficient peak inspiratory flow through the Novolizer, a novel multiple dose dry powder inhaler with acoustic and optical feedback mechanisms for correct inhalation. PATIENTS AND METHODS: 137 children (median age 7 years, range 4-2) with mild to moderate persistent asthma (FEV1 < 90% predicted or pre-treated with low-dose steroids) participated in this open, multi-centre study. After assessment of FEV1 and peak inspiratory flow (without inhalator device, PIF), the children were instructed to inhale with the Novolizer (PIF through inhaler, PIF-N). All assessments were done in triplicate and the mean out of three attempts analysed. RESULTS: Mean PIF was 128 +/- 61 l/min and mean PIF-N was 69 +/- 18 l/min. This is distinctly above the rate necessary to overcome the Novolizer's trigger threshold. PIF performance through the Novolizer was linear in the age interval of 4-8 years, no further increase was observed beyond 8 years. CONCLUSIONS: The medium to low intrinsic resistance of the Novolizer permits a relatively high PIF through this device. Together with the feedback mechanisms, this makes the Novolizer particularly valuable for inhalation therapy in asthmatic children with drugs such as salbutamol, formoterol, or budesonide.

Tolerance and effect of an add-on treatment with a cough medicine containing ivy leaves dry extract on lung function in children with bronchial asthma.

Ivy leaves dry extract is registered as an expectorant in patients with respiratory diseases associated with productive cough. Next to its secretolytical properties, bronchospasmolytical effects are described. However only limited data exist about a possible therapeutical effect in asthmatic patients. In this double blind, placebo-controlled, randomized cross-over study, 30 children (median age 9.07 years (min-max: 6-11)) suffering from partial or uncontrolled mild persistent allergic asthma despite long-term treatment with 400 µg budesonide equivalent were investigated. After a four week run-in period, patients either received ivy leaves dry extract for four weeks in addition to their inhaled corticosteroid therapy or placebo, followed by a wash-out phase before switching to the other treatment arm. Lung function, FeNO, exhaled breath condensate pH and life quality was analyzed after each treatment period. There was a significant improvement of MEF(75-25), MEF25 and VC after treatment with ivy leaves dry extract (MEF(75-25) change in the mean 0.115 l/s, p=0.044; MEF25 change in the mean 0.086 l/s, p=0.041; VC change in the mean 0.052 l, p=0.044), but not after treatment with placebo. For the primary outcome parameters (relative change of FEV1 and MEF(75-25) before bronchodilation) no treatment effect could be detected in the cross-over analysis (FEV1 p=0.6763 and MEF(75-25) p=0.6953). This proof-of-concept study indicates that children with mild uncontrolled asthma despite regular inhaled corticosteroid therapy might benefit from an additional therapy with ivy leaves dry extract. However, further studies are needed.

Leisure time activity and new onset of wheezing during adolescence.

Asthma prevalence is increasing in adult and paediatric patients. In the present study, the association between different leisure time activities and new onset of wheezing was analysed in adolescents aged 16-18 yrs taking part in a questionnaire-based follow-up of the International Study on Asthma and Allergies in Childhood in Munich and Dresden, Germany. Of the 3,785 adolescents who took part in the follow-up (76% response), 2,910 adolescents without earlier episodes of wheezing in childhood were included in the analyses. Of these, 330 (11.3%) reported new onset of wheeze during the previous 12 months. In the bivariate analyses, exercising more than once per week or performing computer work >1 h.day(-1) were inversely related to new onset of wheeze. In contrast, visiting discotheques on a regular basis increased the risk of new onset of wheeze (12.9 versus 9.9%). The observed inverse relationship between physical activity and new onset of wheeze was not an independent effect but mediated by differences in active smoking. The association between physical activity and new onset of wheeze disappeared when active smoking was taken into account. However, the present data do not allow for determining whether smoking operated as a confounder or as an intermediate factor, i.e. whether physical activities prevented active smoking.

First months of employment and new onset of rhinitis in adolescents.

The aim of the present study was to investigate the incidence of rhinitis in adolescents, taking into account the duration and type of employment in holiday and vocational jobs, and to study latency until development of symptoms. Participants of the International Study of Asthma and Allergies in Childhood (ISAAC)-II study in Munich and Dresden (Germany), who were enrolled in 1995, were re-contacted by a postal questionnaire in 2002 (aged 16-18 yrs). The questionnaire focused on allergic rhinitis, type and duration of all jobs, and potential confounders. All jobs held for >/=8 h.week(-1) and >/=1 month were coded and occupational exposure was assigned by a job-exposure matrix. Out of the 3,785 participants, 964 reported an employment history. The median (25th-75th percentile) duration of employment was 10 (1-16) months. After adjusting for potential confounders, those working in high-risk occupations (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.0-2.1) had an increased risk for new onset of rhinitis, especially those exposed to low molecular weight agents (OR 1.8, 95% CI 1.1-2.8). The incidence of rhinitis was highest among those currently employed in a high-risk job for <10 months. Teenagers who start working in high-risk occupations have a higher incidence of rhinitis compared with those not working. This increased risk might occur early on during employment.

Polymorphisms in eosinophil pathway genes, asthma and atopy.

BACKGROUND: Eosinophilic inflammation is considered to play an important role in the development as well as in the perpetuation of asthma. As eosinophil production and survival is under genetic control we investigated whether polymorphisms in eosinophil regulation pathway genes (IL-3, IL-5, GM-CSF and their respective enhancers and receptors) may influence the development of atopic diseases. METHODS: In two large study populations of children, the German part of the International Study of Asthma and Allergy in Childhood (ISAAC II) and the German Multicentre Atopy Study (MAS), 3099 and 824 children, seven polymorphisms previously associated with the development of atopic diseases were genotyped: two in and around the GM-CSF gene (Ile117Thr and T3085G), one in IL-3 (Pro27Ser), in IL-5 (C-746T), and in the IL-5 high affinity receptor chain IL-5R (G-80A) and two in the common receptor chain CSFR2b for IL-3, IL-5, and GM-CSF (Asp312Asn and Glu249Gln). Statistical analyses were performed using chi-squared tests and variance analyses. Gene by gene interactions were evaluated in logistic regression models. RESULTS: The T allele at position -746 in the IL-5 gene was significantly protective for atopy in the ISAAC II population (P = 0.006). Furthermore, the risk for atopic asthma was decreased in carriers of the T allele (P = 0.036) and evidence for interaction with the enhancer polymorphism 3085 bp 3' of GM-CSF was detected. CONCLUSIONS: IL-5 C-746T influenced atopic outcomes and showed evidence for gene by gene interaction. No significant associations were found with all other tested polymorphisms in the eosinophil regulation pathway after correction for multiple testing.

Do respiratory symptoms predict job choices in teenagers?

Existing guidelines advise adolescents with asthma and allergies against high-risk occupations. The aim of the current authors' analyses was to investigate the resulting self-selection in a prospective cohort study. The participants of Phase II of the International Study of Asthma and Allergies in Childhood in Germany (aged 9-11 yrs at baseline) were re-contacted after 7 yrs (response rate was 77%) and were asked to complete a questionnaire, which included items on atopic diseases. The subjects were also asked about the type of job they would like to have in the future (preferred job choice). Exposure to agents with potential asthma risk was evaluated using a job exposure matrix. The analyses were restricted to those in school-based vocational training programmes without occupational exposures. A total of 33% of subjects chose jobs with high asthma risk, 23% selected low asthma risk jobs and the remaining adolescents indicated jobs without known asthma risk (reference category). There were no statistically significant associations between asthma, allergic rhinitis or atopic dermatitis and selecting jobs with asthma risk. Participants with allergic rhinitis tended to select high risk jobs less frequently. In conclusion, self-selection into low risk jobs seems to play a minor role in teenagers with asthma or allergies.

Smoking and the incidence of asthma during adolescence: results of a large cohort study in Germany.

BACKGROUND: The association between smoking and asthma or wheeze has been extensively studied in cross sectional studies, but evidence from large prospective cohort studies on the incidence of asthma during adolescence is scarce. METHODS: We report data from a cohort study in two German cities, Dresden and Munich. The study population (n = 2936) was first studied in 1995/6 at age 9-11 years as part of phase II of the International Study of Asthma and Allergies in Childhood (ISAAC II) and followed up in 2002/3. At baseline the parents completed a questionnaire and children underwent clinical examination and blood sampling. At follow up the young adults completed questionnaires on respiratory health, living, and exposure conditions. Incidence risk ratios (IRR) were calculated and adjusted for potential confounders using a modified Poisson regression approach. RESULTS: The adjusted IRR for incident wheeze for active smokers compared with non-smokers was 2.30 (95% confidence interval (CI) 1.88 to 2.82). The adjusted IRR was slightly higher for incident wheeze without a cold (2.76, 95% CI 1.99 to 3.84) and the incidence of diagnosed asthma (2.56, 95% CI 1.55 to 4.21). Analysis of duration and intensity of active smoking indicated dose dependent associations. Stratified analyses showed that the risk of incident wheeze without a cold in atopic smokers increased with decreasing plasma alpha(1)-antitrypsin levels at baseline (1.64, 95% CI 1.22 to 2.20 per interquartile range). CONCLUSIONS: Active smoking is an important risk factor for the incidence of asthma during adolescence. Relatively lower plasma levels of alpha(1)-antitrypsin, although well above currently accepted thresholds, may increase susceptibility to respiratory disease among atopic smokers.

Exhaled breath condensate: methodological recommendations and unresolved questions.

Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases. The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required. Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them. Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.

Human cytomegalovirus glycoprotein B genotypes in renal transplant recipients.

Based on sequence variation of the glycoprotein B (gB) gene, human cytomegalovirus (HCMV) strains can be classified into four gB genotypes. In a previous study of bone marrow transplant recipients, infection with the gB type 1 correlated with a more favorable clinical outcome than infection with the gB types 2, 3, or 4. The gB type was determined in 60 renal transplant and in 47 bone marrow transplant recipients using PCR and restriction analysis. All HCMV variants in patient specimens could be assigned to one of the four previously described gB types. Two or more specimens obtained from 39 patients were analysed; in 31 of these patients the gB type was the same in all samples. The gB type did not correlate with the clinical outcome or the level of viremia in renal transplant recipients.

Bradycardia and hypoxaemia due to position-dependent hypoperfusion of the brain stem in a preterm infant.

UNLABELLED: The case is reported of a male baby with a decreased time average velocity of the basilar artery to 32%, measured by Doppler sonography in dextro-rotated head position. The decrease was due to a hypoplastic right vertebral artery with compression of the contralateral vertebral artery at the craniocervical junction during dextro-rotation of the head. This finding was more prominent in prone than in supine position. A decrease in oxygen saturation and heart rate to < 70% and 60 bpm, respectively, was monitored during dextro-rotation. The polysomnography also revealed postural-dependent bradycardia, decrease of the oxygen saturation, and rising carbon dioxide partial tension in prone position with dextro-rotation of the head. CONCLUSION: Hypoperfusion of the brain stem caused by postural changes leads to further clinically relevant changes. Therefore an association with an acute life-threatening event and sudden infant death syndrome is speculated.