Combined multidimensional single-cell protein and RNA profiling dissects the cellular and functional heterogeneity of thymic epithelial cells

The network of thymic stromal cells provides essential niches with unique molecular cues controlling T cell development and selection. Recent single-cell RNA sequencing studies have uncovered previously unappreciated transcriptional heterogeneity among thymic epithelial cells (TEC). However, there are only very few cell markers that allow a comparable phenotypic identification of TEC. Here, using massively parallel flow cytometry and machine learning, we deconvoluted known TEC phenotypes into novel subpopulations. Using CITEseq, these phenotypes were related to corresponding TEC subtypes defined by the cells' RNA profiles. This approach allowed the phenotypic identification of perinatal cTEC and their physical localisation within the cortical stromal scaffold. In addition, we demonstrate the dynamic change in the frequency of perinatal cTEC in response to developing thymocytes and reveal their exceptional efficiency in positive selection. Collectively, our study identifies markers that allow for an unprecedented dissection of the thymus stromal complexity, as well as physical isolation of TEC populations and assignment of specific functions to individual TEC subtypes.

Issue 2 - "Update on adverse respiratory effects of indoor air pollution". Part 2): Indoor air pollution and respiratory diseases: Perspectives from Italy and some other GARD countries

OBJECTIVE

to synthesize the Italian epidemiological contribution to knowledge on indoor pollution respiratory impact, and to analyze the perspective of some GARD countries on the health effects of indoor air pollution.

RESULTS

Italian epidemiological analytical studies confirmed a strong relationship between indoor air pollution and health in general population. Environmental tobacco smoke, biomass (wood/coal) fuel for cooking/heating and indoor allergens (house dust mites, cat and dog dander, mold/damp) are the most relevant indoor pollution sources and are related to respiratory and allergic symptoms/diseases in Italy and in other GARD countries such as Mexico, Brazil, Vietnam, India, Nepal and Kyrgyzstan. Community-based global health collaborations are working to improve prevention, diagnosis and care of respiratory diseases around the world, specially in low- and middle-income countries, through research and education.

CONCLUSIONS

in the last thirty years, the scientific evidence produced on respiratory health effects of indoor air pollution has been extensive, but the necessity to empower the synergies between scientific community and local administrations remains a challenge to address in order to implement effective interventions. Based on abundant evidence of indoor pollution health effect, WHO, scientific societies, patient organizations and other members of the health community should work together to pursue the GARD vision of "a world where all people breathe freely" and encourage policy makers to increase their engagement in advocacy for clean air.

Outdoor air pollution and respiratory health

The need to address the impact of air pollution on health is reinforced by recent scientific evidence and the 2021 WHO Air Quality Guidelines (AQG). Air pollution is an avoidable risk factor causing a high burden for society with elevated deaths, health disorders, disabilities and huge socio-economic costs, especially in low- and middle-income countries. We have evaluated recent evidence from international reports, systematic reviews and official websites of international agencies. Growing evidence shows a causal relationship between air pollution exposure and acute lower respiratory infections, chronic obstructive pulmonary disease, asthma and lung cancer. Exposure to air pollution in both the short- and long-term has a serious impact on respiratory health. Harmful effects occur even at very low pollutant concentration levels, and there are no detectable thresholds below which exposure may be considered safe. The adverse respiratory health effects of air pollutants, even at low levels, are confirmed by recent epidemiological studies. Scientific respiratory societies and patient associations, along with other stakeholders in the health sector, should increase their engagement and advocacy to raise awareness of clean air policies and the latest WHO AQG.

Diversity in Cortical Thymic Epithelial Cells Occurs through Loss of a Foxn1-Dependent Gene Signature Driven by Stage-Specific Thymocyte Cross-Talk

In the thymus, cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells support αβT cell development from lymphoid progenitors. For cTECs, expression of a specialized gene signature that includes Cxcl12, Dll4, and Psmb11 enables the cortex to support T lineage commitment and the generation and selection of CD4+CD8+ thymocytes. Although the importance of cTECs in T cell development is well defined, mechanisms that shape the cTEC compartment and regulate its functional specialization are unclear. Using a Cxcl12DsRed reporter mouse model, we show that changes in Cxcl12 expression reveal a developmentally regulated program of cTEC heterogeneity. Although cTECs are uniformly Cxcl12DsRed+ during neonatal stages, progression through postnatal life triggers the appearance of Cxcl12DsRed- cTECs that continue to reside in the cortex alongside their Cxcl12DsRed+ counterparts. This appearance of Cxcl12DsRed- cTECs is controlled by maturation of CD4-CD8-, but not CD4+CD8+, thymocytes, demonstrating that stage-specific thymocyte cross-talk controls cTEC heterogeneity. Importantly, although fate-mapping experiments show both Cxcl12DsRed+ and Cxcl12DsRed- cTECs share a common Foxn1+ cell origin, RNA sequencing analysis shows Cxcl12DsRed- cTECs no longer express Foxn1, which results in loss of the FOXN1-dependent cTEC gene signature and may explain the reduced capacity of Cxcl12DsRed- cTECs for thymocyte interactions. In summary, our study shows that shaping of the cTEC compartment during the life course occurs via stage-specific thymocyte cross-talk, which drives loss of Foxn1 expression and its key target genes, which may then determine the functional competence of the thymic cortex.

Single breath nitrogen test as predictor of lung function decline and COPD over an 8-year follow-up

BACKGROUND

The single breath nitrogen (SBN2) test was proposed for early detection of "small airways disease" in the seventies. Few longitudinal studies have subsequently evaluated the relationships between SBN2 test measurements and lung function decline or COPD incidence.

AIM

This study evaluates whether SBN2 test abnormalities may be significant predictors of lung function decline and COPD incidence over an 8-year follow-up.

STUDY DESIGN AND METHODS

In this longitudinal study, 907 adults (20+ years old; 56% males) from the prospective Po River Delta epidemiological study underwent SBN2 test at baseline and spirometry testing at both baseline and follow-up 8-year apart. Multinomial and multiple regression models were used to assess associations of SBN2 indexes and rates of FEV1 decline or risk of COPD incidence over time, after adjusting for sex, height and baseline age, FEV1 and smoking status. COPD was defined according to either GOLD or ATS-ERS criteria.

RESULTS

Among SBN2 indexes, only the slope of alveolar plateau (N2-slope) was significantly associated with rates of FEV1 decline (7.93 mL/year for a one-unit change in N2-slope, p<0.0001), and with an increased risk of developing COPD as defined by GOLD (RR 1.81, 95%CI 1.29-2.52, mild; RR 2.78, 95%CI 1.70-4.53, moderate or severe obstruction) and ATS-ERS criteria (RR 1.62, 95%CI 1.14-2.29, mild; RR 3.40, 95%CI 1.72-6.73, moderate or severe obstruction).

CONCLUSION

In this population-based study, N2-slope from SBN2 test is a significant predictor of lung function decline and COPD incidence over an 8-year follow-up, confirming the role of the "small airways disease" in the natural history of COPD.

Developmental dynamics of the neural crest-mesenchymal axis in creating the thymic microenvironment

The thymic stroma is composed of epithelial and nonepithelial cells providing separate microenvironments controlling homing, differentiation, and selection of hematopoietic precursor cells to functional T cells. Here, we explore at single-cell resolution the complex composition and dynamic changes of the nonepithelial stromal compartment across different developmental stages in the human and mouse thymus, and in an experimental model of the DiGeorge syndrome, the most common form of human thymic hypoplasia. The detected gene expression signatures identify previously unknown stromal subtypes and relate their individual molecular profiles to separate differentiation trajectories and functions, revealing an unprecedented heterogeneity of different cell types that emerge at discrete developmental stages and vary in their expression of key regulatory signaling circuits and extracellular matrix components. Together, these findings highlight the dynamic complexity of the nonepithelial thymus stroma and link this to separate instructive roles essential for normal thymus organogenesis and tissue maintenance.

Urban grey spaces are associated with increased allergy in the general population

BACKGROUND

the built environment in urban areas may have side effects on children's respiratory health, whilst less is known for adulthood.

AIM

to assess the association between increasing exposure to grey spaces and allergic status in an adult general population sample.

METHODS

2070 subjects (age range 15-84 yrs), living in Pisa/Cascina, Italy, were investigated in 1991-93 through a questionnaire on health status and risk factors, skin prick test (SPT), serum Immunoglobulins E (IgE), and serum antibodies to benzo(a)pyrene diol epoxide (BPDE)-DNA adducts. Land-cover exposure within a 1000 m buffer from each subject's home address was assessed through the CORINE Land Cover program (CLC 1990) within the FP7/HEALS project (2013-2018). Participants' residential addresses were geocoded and the proportion of surrounding grey spaces was calculated. Through logistic regression models, adjusting for potential confounding factors, the effect of a 10% increase in grey spaces exposure on allergic biomarkers/conditions was assessed; the relationship with serum antibodies to BPDE-DNA adducts positivity was also analyzed.

RESULTS

A 10% increase in grey spaces coverage was associated with a higher probability of having SPT positivity (OR 1.07, 95% CI 1.02-1.13), seasonal SPT positivity (OR 1.12, 1.05-1.19), polysensitization (OR 1.11, 1.04-1.19), allergic rhinitis (OR 1.10, 1.04-1.17), co-presence of SPT positivity and asthma/allergic rhinitis (OR 1.16, 1.08-1.25), asthma/allergic rhinitis (OR 1.06, 1.00-1.12), presence of serum antibodies to BPDE-DNA adducts positivity (OR 1.07, 1.01-1.14).

CONCLUSIONS

grey spaces have adverse effects on allergic status and are related to a biomarker of polycyclic aromatic hydrocarbons exposure in adulthood. Thus, they may be used as a proxy of urban environmental exposure.

FOXN1 forms higher-order nuclear condensates displaced by mutations causing immunodeficiency

The transcription factor FOXN1 is a master regulator of thymic epithelial cell (TEC) development and function. Here, we demonstrate that FOXN1 expression is differentially regulated during organogenesis and participates in multimolecular nuclear condensates essential for the factor’s transcriptional activity. FOXN1’s C-terminal sequence regulates the diffusion velocity within these aggregates and modulates the binding to proximal gene regulatory regions. These dynamics are altered in a patient with a mutant FOXN1 that is modified in its C-terminal sequence. This mutant is transcriptionally inactive and acts as a dominant negative factor displacing wild-type FOXN1 from condensates and causing athymia and severe lymphopenia in heterozygotes. Expression of the mutated mouse ortholog selectively impairs mouse TEC differentiation, revealing a gene dose dependency for individual TEC subtypes. We have therefore identified the cause for a primary immunodeficiency disease and determined the mechanism by which this FOXN1 gain-of-function mutant mediates its dominant negative effect.

RBFOX splicing factors contribute to a broad but selective recapitulation of peripheral tissue splicing patterns in the thymus

Thymic epithelial cells (TEC) control the selection of a T cell repertoire reactive to pathogens but tolerant of self. This process is known to involve the promiscuous expression of virtually the entire protein-coding gene repertoire, but the extent to which TEC recapitulate peripheral isoforms, and the mechanisms by which they do so, remain largely unknown. We performed the first assembly-based transcriptomic census of transcript structures and splicing factor (SF) expression in mouse medullary TEC (mTEC) and 21 peripheral tissues. Mature mTEC expressed 60.1% of all protein-coding transcripts, more than was detected in any of the peripheral tissues. However, for genes with tissue-restricted expression, mTEC produced fewer isoforms than did the relevant peripheral tissues. Analysis of exon inclusion revealed an absence of brain-specific microexons in mTEC. We did not find unusual numbers of novel transcripts in TEC, and we show that Aire, the facilitator of promiscuous gene expression, promotes the generation of long “classical” transcripts (with 5′ and 3′ UTRs) but has only a limited impact on alternative splicing in mTEC. Comprehensive assessment of SF expression in mTEC identified a small set of nonpromiscuously expressed SF genes, among which we confirmed RBFOX to be present with AIRE in mTEC nuclei. Using a conditional loss-of-function approach, we show that Rbfox2 promotes mTEC development and regulates the alternative splicing of promiscuously expressed genes. These data indicate that TEC recommission a small number of peripheral SFs, including members of the RBFOX family, to generate a broad but selective representation of the peripheral splice isoform repertoire.

Combined immunodeficiency with autoimmunity caused by a homozygous missense mutation in inhibitor of nuclear factor 𝛋B kinase alpha (IKKα)

[Figure: see text].

The chaperonin CCT8 controls proteostasis essential for T cell maturation, selection, and function

T cells rely for their development and function on the correct folding and turnover of proteins generated in response to a broad range of molecular cues. In the absence of the eukaryotic type II chaperonin complex, CCT, T cell activation induced changes in the proteome are compromised including the formation of nuclear actin filaments and the formation of a normal cell stress response. Consequently, thymocyte maturation and selection, and T cell homeostatic maintenance and receptor-mediated activation are severely impaired. In the absence of CCT-controlled protein folding, Th2 polarization diverges from normal differentiation with paradoxical continued IFN-γ expression. As a result, CCT-deficient T cells fail to generate an efficient immune protection against helminths as they are unable to sustain a coordinated recruitment of the innate and adaptive immune systems. These findings thus demonstrate that normal T cell biology is critically dependent on CCT-controlled proteostasis and that its absence is incompatible with protective immunity.

Inborn errors of thymic stromal cell development and function

As the primary site for T cell development, the thymus is responsible for the production and selection of a functional, yet self-tolerant T cell repertoire. This critically depends on thymic stromal cells, derived from the pharyngeal apparatus during embryogenesis. Thymic epithelial cells, mesenchymal and vascular elements together form the unique and highly specialised microenvironment required to support all aspects of thymopoiesis and T cell central tolerance induction. Although rare, inborn errors of thymic stromal cells constitute a clinically important group of conditions because their immunological consequences, which include autoimmune disease and T cell immunodeficiency, can be life-threatening if unrecognised and untreated. In this review, we describe the molecular and environmental aetiologies of the thymic stromal cell defects known to cause disease in humans, placing particular emphasis on those with a propensity to cause thymic hypoplasia or aplasia and consequently severe congenital immunodeficiency. We discuss the principles underpinning their diagnosis and management, including the use of novel tools to aid in their identification and strategies for curative treatment, principally transplantation of allogeneic thymus tissue.

Ageing compromises mouse thymus function and remodels epithelial cell differentiation

Ageing is characterised by cellular senescence, leading to imbalanced tissue maintenance, cell death and compromised organ function. This is first observed in the thymus, the primary lymphoid organ that generates and selects T cells. However, the molecular and cellular mechanisms underpinning these ageing processes remain unclear. Here, we show that mouse ageing leads to less efficient T cell selection, decreased self-antigen representation and increased T cell receptor repertoire diversity. Using a combination of single-cell RNA-seq and lineage-tracing, we find that progenitor cells are the principal targets of ageing, whereas the function of individual mature thymic epithelial cells is compromised only modestly. Specifically, an early-life precursor cell population, retained in the mouse cortex postnatally, is virtually extinguished at puberty. Concomitantly, a medullary precursor cell quiesces, thereby impairing maintenance of the medullary epithelium. Thus, ageing disrupts thymic progenitor differentiation and impairs the core immunological functions of the thymus.

Biologically indeterminate yet ordered promiscuous gene expression in single medullary thymic epithelial cells

To induce central T-cell tolerance, medullary thymic epithelial cells (mTEC) collectively express most protein-coding genes, thereby presenting an extensive library of tissue-restricted antigens (TRAs). To resolve mTEC diversity and whether promiscuous gene expression (PGE) is stochastic or coordinated, we sequenced transcriptomes of 6,894 single mTEC, enriching for 1,795 rare cells expressing either of two TRAs, TSPAN8 or GP2. Transcriptional heterogeneity allowed partitioning of mTEC into 15 reproducible subpopulations representing distinct maturational trajectories, stages and subtypes, including novel mTEC subsets, such as chemokine-expressing and ciliated TEC, which warrant further characterisation. Unexpectedly, 50 modules of genes were robustly defined each showing patterns of co-expression within individual cells, which were mainly not explicable by chromosomal location, biological pathway or tissue specificity. Further, TSPAN8+ and GP2+ mTEC were randomly dispersed within thymic medullary islands. Consequently, these data support observations that PGE exhibits ordered co-expression, although mechanisms underlying this instruction remain biologically indeterminate. Ordered co-expression and random spatial distribution of a diverse range of TRAs likely enhance their presentation and encounter with passing thymocytes, while maintaining mTEC identity.

Keratinocyte growth factor impairs human thymic recovery from lymphopenia

BACKGROUND

The lymphocyte-depleting antibody alemtuzumab is a highly effective treatment of relapsing-remitting multiple sclerosis (RRMS); however 50% of patients develop novel autoimmunity post-treatment. Most at risk are individuals who reconstitute their T-cell pool by proliferating residual cells, rather than producing new T-cells in the thymus; raising the possibility that autoimmunity might be prevented by increasing thymopoiesis. Keratinocyte growth factor (palifermin) promotes thymopoiesis in non-human primates.

METHODS

Following a dose-tolerability sub-study, individuals with RRMS (duration ≤10 years; expanded disability status scale ≤5·0; with ≥2 relapses in the previous 2 years) were randomised to placebo or 180mcg/kg/day palifermin, given for 3 days immediately prior to and after each cycle of alemtuzumab, with repeat doses at M1 and M3. The interim primary endpoint was naïve CD4+ T-cell count at M6. Exploratory endpoints included: number of recent thymic-emigrants (RTEs) and signal-joint T-cell receptor excision circles (sjTRECs)/mL of blood. The trial primary endpoint was incidence of autoimmunity at M30.

FINDINGS

At M6, individuals receiving palifermin had fewer naïve CD4+T-cells (2.229x107/L vs. 7.733x107/L; p=0.007), RTEs (16% vs. 34%) and sjTRECs/mL (1100 vs. 3396), leading to protocol-defined termination of recruitment. No difference was observed in the rate of autoimmunity between the two groupsConclusion: In contrast to animal studies, palifermin reduced thymopoiesis in our patients. These results offer a note of caution to those using palifermin to promote thymopoiesis in other settings, particularly in the oncology/haematology setting where alemtuzumab is often used as part of the conditioning regime.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01712945Funding: MRC and Moulton Charitable Foundation.

Comprehensively Profiling the Chromatin Architecture of Tissue Restricted Antigen Expression in Thymic Epithelial Cells Over Development

Thymic epithelial cells (TEC) effect crucial roles in thymopoiesis including the control of negative thymocyte selection. This process depends on their capacity to express promiscuously genes encoding tissue-restricted antigens. This competence is accomplished in medullary TEC (mTEC) in part by the presence of the transcriptional facilitator AutoImmune REgulator, AIRE. AIRE-regulated gene transcription is marked by repressive chromatin modifications, including H3K27me3. When during TEC development these chromatin marks are established, however, remains unclear. Here we use a comprehensive ChIP-seq dataset of multiple chromatin modifications in different TEC subtypes to demonstrate that the chromatin landscape is established early in TEC differentiation. Much of the chromatin architecture found in mature mTEC was found to be present already over earlier stages of mTEC lineage differentiation as well as in non-TEC tissues. This was reflected by the fact that a machine learning approach accurately classified genes as AIRE-induced or AIRE-independent both in immature and mature mTEC. Moreover, analysis of TEC specific enhancer elements identified candidate transcription factors likely to be important in mTEC development and function. Our findings indicate that the mature mTEC chromatin landscape is laid down early in mTEC differentiation, and that AIRE is not required for large-scale re-patterning of chromatin in mTEC.

RItA: The Italian severe/uncontrolled asthma registry

BACKGROUND

The Italian severe/uncontrolled asthma (SUA) web-based registry encompasses demographic, clinical, functional, and inflammatory data; it aims to raise SUA awareness, identifying specific phenotypes and promoting optimal care.

METHODS

Four hundred and ninety three adult patients from 27 Italian centers (recruited in 2011-2014) were analyzed.

RESULTS

Mean age was 53.8 years. SUA patients were more frequently female (60.6%), with allergic asthma (83.1%). About 30% showed late onset of asthma diagnosis/symptoms (>40 years); the mean age for asthma symptoms onset was 30.2 years and for asthma diagnosis 34.4 years. 97.1% used ICS (dose 2000 BDP), 93.6% LABA in association with ICS, 53.3% LTRAs, 64.1% anti-IgE, 10.7% theophylline, and 16.0% oral corticosteroids. Mean FEV₁ % pred of 75.1%, median values of 300/mm³ of blood eosinophil count, 323 kU/L of serum total IgE, and 24 ppb of FENO were shown. Most common comorbidities were allergic rhinitis (62.4%), gastroesophageal reflux (42.1%), sinusitis (37.9%), nasal polyposis (30.2%), and allergic conjunctivitis (30.2%). 55.7% of SUA patients had exacerbations in the last 12 months, 9.7% emergency department visits, and 7.3% hospitalizations. Factors associated with exacerbation risk were obesity (OR, 95% CI 2.46, 1.11-5.41), psychic disorders (2.87, 0.89-9.30-borderline), nasal polyps (1.86, 0.88-3.89-borderline), partial/poor asthma treatment adherence (2.54, 0.97-6.67-borderline), and anti-IgE use in a protective way (0.26, 0.12-0.53). Comparisons to severe asthma multicenter studies and available registries showed data consistency across European and American populations.

CONCLUSIONS

An international effort in the implementation of SUA patients' registries could help to better understand the clinical features and to manage severe asthma, representing a non-negligible socioeconomic burden for health services.

In situ functional dissection of RNA cis-regulatory elements by multiplex CRISPR-Cas9 genome engineering

RNA regulatory elements (RREs) are an important yet relatively under-explored facet of gene regulation. Deciphering the prevalence and functional impact of this post-transcriptional control layer requires technologies for disrupting RREs without perturbing cellular homeostasis. Here we describe genome-engineering based evaluation of RNA regulatory element activity (GenERA), a clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 platform for in situ high-content functional analysis of RREs. We use GenERA to survey the entire regulatory landscape of a 3′UTR, and apply it in a multiplex fashion to analyse combinatorial interactions between sets of miRNA response elements (MREs), providing strong evidence for cooperative activity. We also employ this technology to probe the functionality of an entire MRE network under cellular homeostasis, and show that high-resolution analysis of the GenERA dataset can be used to extract functional features of MREs. This study provides a genome editing-based multiplex strategy for direct functional interrogation of RNA cis-regulatory elements in a native cellular environment.

RNA regulatory elements (RREs) are important post-transcriptional control features but studying them requires disrupting their activity without disturbing cellular homeostasis. Here the authors present GenERA, a CRISPR-Cas9 screening platform of in situ analysis of native RREs.

Foxn1 regulates key target genes essential for T cell development in postnatal thymic epithelial cells

Thymic epithelial cell differentiation, growth and function depend on the expression of the transcription factor Foxn1, however its target genes have never been physically identified. Using novel static and inducible genetic model systems and chromatin studies, we provide now a genome wide map of direct Foxn1 target genes for postnatal thymic epithelia and define the Foxn1 binding motif. We detail the function of Foxn1 in these cells and demonstrate that in addition to the transcriptional control of genes involved in the attraction and lineage commitment of T cell precursors, Foxn1 regulates the expression of genes involved in antigen processing and thymocyte selection. Thus, critical events in thymic lympho-stromal cross-talk and T cell selection are indispensably choreographed by Foxn1.

Characteristics and predictors of allergic rhinitis undertreatment in primary care

Although allergic rhinitis is considered a raising medical problem in many countries it is often undertreated. The reasons for this phenomenon are not completely clear.The aim of this study is to evaluate factors associated with allergic rhinitis under-/no treatment.A sample of 518 allergic rhinitis patients recruited by their primary care physicians, as a part of the ARGA study, were invited to fill in a specific questionnaire regarding rhinitis symptoms, treatment, and rhinitis-related work/social disability. Chi-square test and logistic regression were performed to assess risk factors for allergic rhinitis under-/no treatment.Over one out of four patients had no treatment despite the symptoms and 13.5% were inadequately treated. Participants with asthma (OR 0.47, 95% CI 0.30-0.75) and conjunctivitis (0.44, 95% CI 0.27-0.71) were at lower risk of allergic rhinitis under-/no treatment: in asthmatics this reduction was related mainly to the concomitant asthma treatment (OR 0.19, 95% CI 0.10-0.37).Asthmatics with under-/not treated rhinitis had the highest prevalence of rhinitis-related quality of life impairment.Under-/no treatment for allergic rhinitis is still rather frequent despite the relevance of this disease. The simultaneous presence of asthma and an anti-asthmatic therapy are able to influence positively the treatment. Targeted interventions toward a better characterization and a tight follow-up of rhinitis patient without asthma are needed.

Air quality of nursing homes and its effect on the lung health of elderly residents

In industrialized countries the elderly spend most of their time indoors. The elderly may be at a higher risk of suffering from indoor air pollution-related diseases compared to the rest of the population, because of their increased exposure to potential indoor risk factors. This editorial aims to critically analyze the recent literature regarding this important topic. Results of studies performed on the elderly living in nursing homes clearly highlight that they are at risk of respiratory health impairment, even at moderate air pollutant concentrations, particularly if they are over 80 years of age and living in poorly ventilated nursing homes. The future epidemiological research on ageing and respiratory diseases should investigate the underlying biological and physiological mechanisms, in addition to the adverse health effects of potential indoor risk factors, in order to help defining effective strategies for healthy ageing.

Allergy and asthma: Effects of the exposure to particulate matter and biological allergens

The prevalence of asthma and allergies including atopy has increased during the past decades, particularly in westernized countries. The rapid rise in the prevalence of such diseases cannot be explained by genetic factors alone. Rapid urbanization and industrialization throughout the world have increased air pollution and population exposures, so that most epidemiologic studies are focusing on possible links between air pollution and respiratory diseases. Furthermore, a growing body of evidence shows that chemical air pollution may interact with airborne allergens enhancing the risk of atopic sensitization and exacerbation of symptoms in sensitized subjects. These phenomena are supported by current in vitro and animal studies showing that the combined exposure to air pollutants and allergens may have a synergistic or additive effect on asthma and allergies, although there is an insufficient evidence about this link at the population level. Further research is needed in order to elucidate the mechanisms by which pollutants and biological allergens induce damage in exposed subjects. The abatement of the main risk factors for asthma and allergic diseases may achieve huge health benefits. Thus, it is important to raise awareness of respiratory allergies as serious chronic diseases which place a heavy burden on patients and on society as a whole.

COPD management according to old and new GOLD guidelines: an observational study with Italian general practitioners

BACKGROUND

Guideline recommendations for COPD management are only partially applied within primary care clinical practice.

OBJECTIVE

To compare the COPD management by Italian general practitioners (GPs) according to either the old GOLD (oGOLD) or the new GOLD (nGOLD) guidelines.

RESEARCH DESIGN AND METHODS

Observational study in different Italian areas. A total of 176 GPs enrolled their patients with a COPD diagnosis. Questionnaires were used to collect data on: COPD symptoms, disease severity, exacerbations, prescribed pharmacological and non-pharmacological treatments. COPD severity was estimated according to oGOLD and nGOLD guidelines.

RESULTS

A total of 526 subjects had complete information to assess COPD severity level according to guidelines (symptoms level, spirometry, history of exacerbations). The investigated subjects were more frequently males (71.2%) with a mean age of 72.5 years, and ex-smokers (44.4%). GPs reported sufficient control of the disease in 47.2% of the subjects with over two exacerbations in the last 12 months. Most patients have moderate COPD (51.5%), according to oGOLD, and belong to D groups (high risk, more symptoms) (45.6%), according to nGOLD. Overall, a low use of post-bronchodilator spirometry (65.1%) and of pulmonary rehabilitation (13.4%) was shown. The results highlighted a low prescriptive appropriateness but with higher value according to nGOLD than oGOLD: 61.4% vs 35.6%.

STUDY LIMITATIONS

Prescription data only provide limited information to judge prescribing quality, thus the results have to be evaluated with caution; moreover, this study was not designed to assess the difference between oGOLD and nGOLD.

CONCLUSIONS

Guideline recommendations are applied only partially within clinical practice. A higher prescriptive appropriateness is shown by GPs using nGOLD classification. This might be due to the fact that nGOLD, with respect to oGOLD, takes into account anamnestic usual features considered by GPs in their clinical practice.

Adverse respiratory effects of outdoor air pollution in the elderly

Compared to the rest of the population, the elderly are potentially highly susceptible to the effects of outdoor air pollution due to normal and pathological ageing. The purpose of the present review was to gather data on the effects on respiratory health of outdoor air pollution in the elderly, on whom data are scarce. These show statistically significant short-term and chronic adverse effects of various outdoor air pollutants on cardiopulmonary morbidity and mortality in the elderly. When exposed to air pollution, the elderly experience more hospital admissions for asthma and chronic obstructive pulmonary disease (COPD) and higher COPD mortality than others. Previous studies also indicate that research on the health effects of air pollution in the elderly has been affected by methodological problems in terms of exposure and health effect assessments. Few pollutants have been considered, and exposure assessment has been based mostly on background air pollution and more rarely on objective measurements and modelling. Significant progress needs to be made through the development of 'hybrid' models utilising the strengths of information on exposure in various environments to several air pollutants, coupled with daily activity exposure patterns. Investigations of chronic effects of air pollution and of multi-pollutant mixtures are needed to better understand the role of air pollution in the elderly. Lastly, smoking, occupation, comorbidities, treatment and the neighbourhood context should be considered as confounders or modifiers of such a role. In this context, the underlying biological, physiological and toxicological mechanisms need to be explored to better understand the phenomenon through a multidisciplinary approach.

The ARGA study with Italian general practitioners: prescriptions for allergic rhinitis and adherence to ARIA guidelines

BACKGROUND

General practitioners (GPs) are the healthcare professionals to whom patients with rhinitis firstly refer for their symptoms.

OBJECTIVE

In the present study, we assessed drug prescriptions for allergic rhinitis (AR) and evaluated prescriptive adherence to ARIA treatment guidelines.

METHODS

Data on 1379 AR patients were collected by 107 Italian GPs. Adherence to ARIA guidelines was evaluated according to AR severity classification.

RESULTS

AR was diagnosed by GPs as mild intermittent for 46.2% of patients, mild persistent for 26.6%, moderate-severe intermittent for 20.2%, and moderate-severe persistent for 7%; 43.7% of AR patients had concomitant asthma. The most frequently prescribed therapeutic groups were antihistamines (anti-H, 76%) and nasal corticosteroids (NCS, 46%). Anti-H were significantly used more often to treat AR alone than AR + asthma (85 vs. 68%, p < 0.001), whereas NCS were used more often to treat AR + asthma than AR alone (50 vs. 42%, p = 0.01). Among patients with only mild intermittent AR, 39% were prescribed combined therapy. Among patients with moderate-severe persistent AR, 30% of those with AR alone and 18% of those with AR + asthma were prescribed monotherapy based on anti-H. GPs were more compliant with ARIA guidelines while treating AR alone (57%) than AR + asthma (46%) patients. The adherence increased according to the severity grade and was satisfactory for moderate-severe persistent AR (89% for AR alone and 95% for AR + asthma).

CONCLUSIONS

Adherence to ARIA guidelines is satisfactory only for treatment of more severe patients, thus GPs often tend to treat patients independently from ARIA guidelines. Since prescription data only provide limited information to judge prescribing quality, some deviation from the gold standard are to be expected.

Congruence between international guidelines and mite specific immunotherapy prescribing practices

Both rhinitis (ARIA) and asthma (GINA) guidelines recommend allergen-specific immunotherapy (SIT) tailored to the specific levels of severity of each disease. Real world studies evaluating congruence between these recommendations and prescribing practice in the single patient with comorbidity are lacking. An observational polycentric study was carried out in 518 patients recruited from 34 allergy centers throughout Italy. A questionnaire was administered to each consecutive patient over a span of four months. Taking into account guideline recommendations for both diseases, concomitant in the same patient, three subsets resulted: patients not eligible for SIT (11%); patients eligible for SIT for one disease only (60%); patients eligible for SIT for both diseases (29%). SIT was prescribed in 257 (49.6%) subjects. The level of SIT prescription was about 50% in all three groups. Consistent with the ARIA guidelines, a correlation between the prescription of SIT and the severity of rhinitis was documented (r=0.87; p=0.001). An association with asthma severity was found (p=0.02), but the trend was inconsistent with the GINA recommendations. Young age was the most important factor for SIT prescription both in the eligible for one disease and in the eligible for both diseases subset. The tendency towards worsening of symptoms was a factor for SIT in the eligible for one disease subset. In mite allergic patients with rhinitis and asthma comorbidity, the severity of rhinitis and the young age are the most important factors driving the SIT prescription. The congruence of SIT prescription was better for the ARIA than GINA guidelines.

[Epidemiology of the chronic obstructive pulmonary disease: environmental and occupational risk]

FACTORS. Chronic Obstructive Pulmonary Disease (COPD) is a very important cause of morbidity and mortality in industrialized and developing countries. According to the World Health Organization (WHO), in 2020 COPD will become the third leading cause of death all over the world. To date, several risk factors for developing COPD have been studied. They can act either singly or interacting among themselves in a synergistic way. Smoking habits and aging are the most important factor for development and exacerbation of COPD, but environmental conditions, such as air pollution and work exposure, can be relevant factors. Recommendations for the prevention of COPD, beside the promotion of smoking cessation, may be air pollution abatement and control of professional exposure. In view of historical trend of risk factors exposure, further epidemiological studies are necessary for a better knowledge of COPD natural history.

4.5-Mb YAC STS contig at 50-kb resolution, spanning Xq25 deletions in two patients with lymphoproliferative syndrome

Sequence-tagged site (STS) content mapping in yeast artificial chromosomes (YACs) was used to cover the region deleted in two patients affected with X-linked lymphoproliferative disorder. The order of markers includes, centromere to telomere, DXS8009-DXS1206-DXS8078-DXS8044-DXS982- DXS6811-DXS8093-AFM240xblO- DXS75-DXS737-DXS100-DXS6-DXS1046-DXS803 8. The order of six major markers is confirmed by fluorescent in situ hybridization, and all the markers assigned by linkage mapping fall within a 1.6-cM interval. The contig comprises 90 clones containing 89 STSs, yielding a resolution of 50 kb; DNA in a gap just telomeric to DXS8044 has not been found in > 20 equivalents of YACs or bacterial clones. The two deletions were found to have centromeric breakpoints that lie close to DXS1206 and may be identical; the telomeric breakpoints are -150 kb apart, one falling between DXS737 and DXS100, the other between DXS100 and DXS1046. Several STSs near the breakpoints show weak amplification from more than one site; one gives products from three groups of YACs, and lie, respectively, within 50 kb of the centromeric and the two telomeric deletion borders. Such partially duplicated segments of DNA are candidates for involvement in the formation of the deletions.