Luís Taborda-Barata

Prevalence of latex sensitization and allergy in Portuguese children

The prevalence of latex allergy has been increasing not only in risk groups but also in the general population, where it is accepted to average 1%. In children, latex sensitization prevalence studies are scarce and involve different population sampling and allergy testing methods, which makes it difficult to compare across studies. Nevertheless, existing studies point towards a low prevalence of latex allergy in children, which still needs to be confirmed in the Portuguese population. Aiming at studying the prevalence of latex sensitization and allergy in a sample of Portuguese children, we studied 182 children from two different hospital outpatient clinics. A standardized questionnaire focusing on atopic background, previous history and allergic signs or symptoms on exposure to latex or fruits was given to all children and parents. Skin prick testing was performed with a battery of common aeroallergens as well as latex. Serum total IgE, Phadiatop, F × 5E and latex‐specific IgE were determined in all children. Specific IgE to latex‐crossreacting fruits was determined in latex‐sensitized children. Based upon the questionnaire, the prevalence of latex allergy would be 0.5%. The prevalence of latex sensitization would be 3.8%, when based solely upon skin prick testing, and 12.1% (≥0.35 IU/ml) or 6.6% (≥0.70 IU/ml) when based singly upon determination of latex‐specific IgE. When positive results for either test were considered, the prevalence of latex sensitization was 14.3%. All latex‐sensitized children were atopic. Sensitivity to latex‐crossreacting foodstuffs was demonstrated in 61.5% of latex‐sensitized children (16/26). This study shows that the prevalence of latex allergy and sensitization in Portuguese atopic and non‐atopic children, as analysed using various diagnostic methods, is similar to that observed in other countries. In addition, the assessment of latex allergy and sensitization should always include skin prick testing and determination of serum IgE.

Levels of TBT and other selected organotin compounds in duplicate diet samples.

Organotin compounds (OTs) are ubiquitous contaminants with a broad range of applications ranging from biocides and pesticides to catalysts for the production of polyurethane foams and silicones. The deleterious effects of some OTs (particularly tributyltin - TBT) upon wildlife and experimental animals are well documented and include endocrine disruption, immunotoxicity, neurotoxicity, genotoxicity and metabolic dysfunction in which obesity is included. However, virtually no data on the current human exposure levels is available. In order to bridge this gap, we quantified for the first time the levels of OTs in duplicate diet samples from members of the University of Aveiro in Portugal. OTs were detected in 32% of the 28 diet samples analyzed, at relatively low levels. TBT and monobutyltin were detected only in two samples and dibutyltin was detectable in three samples. Dioctyltin was quantified in four samples and monooctyltin in three samples. Phenyltins were below the detection limit in all the diet samples analyzed. Overall, for the vast majority of the samples (89%), the estimated daily intakes (EDI) of organotins through food were much lower than the established tolerable daily intakes (TDI). Hence, for the majority of the participants the risk associated with food ingestion is low.

Serum biomarkers in elderly asthma

Abstract Objective: Asthma is usually misdiagnosed and under-treated in the elderly population, resulting in complications and increased severity to the patient. In this review, we describe some of the most important serum markers of asthma studied so far, reporting their outcomes and possible prediction of asthma in the elderly population. Methods: The PubMed electronic database was used to search for promising serum biomarkers of asthma studied in original articles published in peer-reviewed journals from 2000 to January 2013. Results: A total of 13 relevant serum biomarkers were selected, including IgE, CRP, high sensitive CRP, IL-6, IL-8, IL-17, TNF-α, neopterin, serum amyloid A, eosinophil cationic protein, leukolysin, YKL-40 and soluble CD86. Conclusions: Although the major focus of treatment and research has been on allergic asthma, several forms of the disease are recognized, such as neutrophilic asthma, which is characteristic of older patients. Different phenotypes imply different treatments and so it becomes important to correctly determine which type of asthma the patient is suffering from. Serum markers capable of supporting a diagnosis of asthma are needed in order to counter mistreatment and misdiagnosis with other obstructive airways disease (OAD) in elderly patients. As convenient as serum markers may seem to be, a marker capable of accurately identifying asthma with sufficient specificity is yet to be found.

T cells in sputum of asthmatic patients are activated independently of disease severity or control

BACKGROUND T cells play an important role in bronchial asthma. Although airway CD4+ T cells have been extensively studied previously, there are hardly any studies relating CD8+ T cell activation and disease symptoms. OBJECTIVES The aim of this study was to analyse the association between T cell activation in induced sputum T cells and asthma severity and control; and to evaluate T cell subpopulations in the same subgroups. METHODS Fifty allergic asthmatic patients were recruited and lung function testing was performed. Airway cells were obtained by sputum induction via inhalation of hypertonic saline solution. CD3, CD4, CD8, CD28, CD25 and CD69 were studied by flow cytometry in whole induced sputum and peripheral blood cells. RESULTS Total induced sputum T cells and CD8+ T cells had a higher relative percentage of the activation markers CD25 and CD69 in comparison with peripheral blood. In sputum, the relative percentage of CD25 was higher in CD4+ T cells when compared to CD8+ T cells and the reverse was true regarding CD69. However, neither disease severity nor control were associated with the relative percentage of CD25 or CD69 expression on T cells in sputum. CONCLUSIONS Both CD4+ and CD8+ T cells are activated in the lungs and peripheral blood of asthmatic patients. However, with the possible exception of CD69+ CD8+ T lymphocytes in the sputum, there is no association between T cell activation phenotype in the target organ and disease severity or control.

Socio-epidemiological Aspects of Respiratory Allergic Diseases in Southern Africa

The prevalence of respiratory allergic diseases has been increasing in Southern Africa both in urban and in rural environments. Various factors may contribute toward this situation, namely, exposure to aeroallergens, such as grass pollens and house dust mites. However, other irritant environmental triggers, such as exposure to tobacco smoke and certain indoor and outdoor fumes, may also play a relevant part. Furthermore, certain parasitic and mycobacterial infections may act as allergic disease risk modifiers, although such an influence should be confirmed. Finally, certain cultural and socioeconomic factors may also influence accessibility to healthcare and adherence to treatment of these diseases.

Delivery and recording of smoking cessation advice in a Portuguese teaching hospital: the need for a systemic approach

Background: Smoking cessation should be a top priority in hospitals. In November 2007, a Portuguese teaching hospital carried out a survey to evaluate cessation attitudes, clinical practices and cessation training needs among hospital-based healthcare providers (HCPs). The study also aimed to identify factors associated with cessation attitudes and practices, self-confidence to intervene and awareness of training programs. Method: This is a cross sectional questionnaire-based study including all HCPs. Sample: The study sample covers 424 HCPs, of which 65.4% were females. Mean age of these HCPs was 38.7 ± 10.1 years and the overall response rate was 50.5%. For data analyses, chi-squared tests, McNemar tests and multiple logistic regression models were used. Results: Most physicians and nurses reported “Asking” and “Advising” always or often. Other HCPs reported low frequencies of “Asking” and “Advising” (p < 0.001). Systematic “Asking” was reported less often than “Advising” (p < 0.001). Most HCPs did not record cessation practices, lacked specific training, and were not aware of their training needs. Reported self-confidence, positive attitudes and being a physician or non-smoker were the factors that influenced cessation practices the most. Conclusion: The findings suggest that there is reason to doubt that cessation practices are being undertaken effectively. Hospitals should audit smoking status recording, delivery of effective cessation advice and post-discharge support. Cessation indicators should be mandatory in all healthcare settings. To achieve these goals, undergraduate and graduate cessation training must be given higher priority.

Demographic, laboratory and clinical characterisation of adult portuguese asthmatic patients

BACKGROUND Asthma is a heterogeneous chronic inflammatory condition characterised by reversible airway obstruction and hyperresponsiveness associated with underlying bronchial inflammation and structural changes. It represents an increasing health problem and is a huge burden on the patients, their families and society. The aim of the study was to characterise the adult asthmatic population attending a Hospital Allergy Clinic between the years of 2003 and 2006. METHODS Clinical files from the Allergy Outpatient Clinic of Cova da Beira Hospital were sequentially studied. The total population analysed included 335 female and 130 male asthmatic patients. Bronchial asthma was characterised by clinical history, skin prick testing to aeroallergens, determination of total and specific IgE and lung function testing, and classified according to international guidelines. RESULTS Of the patients studied, 70 % had allergic asthma, and 30 % had non-allergic asthma. When compared to allergic asthma, non-allergic asthma was more frequently associated with older age, perennial symptoms and female gender. More allergic than non-allergic asthma patients also had rhinitis and the reverse was true regarding drug allergy and oesophageal reflux. Grass pollen and mites were the major sensitisers for allergic asthmatics. The sensitisation profile was significantly different between urban- and rural-based asthmatic patients regarding tree pollen, fungi and moulds. CONCLUSIONS In this population, rhinitis was more frequently associated with allergic than with non-allergic asthma. The two types of asthma did not differ in clinical severity or changes in lung function. Sensitisation profiles were different between the urban and rural patients.

Characterization of Fungal Communities in House Dust Samples Collected From Central Portugal—A Preliminary Survey

House dust is a repository and concentrator of many chemical and biological agents including fungi. Considering that dust acts as a long-term reservoir of airborne fungi and that cumulative exposure is more relevant to potential health problems than single-day or short-term exposure, characterization of fungal communities in dust samples is of paramount importance. In the present study, the fungal composition of Portuguese house dust samples was determined. A total of 28 samples were obtained from vacuum cleaner deposits from households located in central Portugal. DNA was extracted from dust samples and fungal communities were analyzed using a culture-independent polymerase chain reaction (PCR)– denaturing gradient gel electrophoresis (DGGE) approach. Cultural analyses were also performed in order to identify the viable fungi species present in selected samples. Fungal diversity, reported as the number of operational taxonomic units (OTU), varied between 9 and 56 OTU. This analysis of viable fungi showed that Aspergillus was the most abundant genus, followed by Penicillium, Mucor, and Rhizomucor. Trichoderma, Chrysosporium, Fusarium, Rhizopus, and Stachybotrys were found in a limited number of houses. Our results demonstrated that dust is, in fact, home for a diverse and heterogeneous fungal community and that some of the species found are known allergic agents with severe negative impacts on human health.

Functional and phenotypic characterization of CD8+CD28+ and CD28­ T cells in atopic individuals sensitized to Dermatophagoides pteronyssinus

BACKGROUND CD8+ T suppressor cells may play a role in immunoregulation. Recent studies have characterized this population by the lack of the CD28 molecule. These CD8+CD28 T cells differ phenotypically and functionally from CD8 + CD28 + T cells. Little is known about CD8 + CD28 cells in atopy. Our aim was to analyze the phenotype and functional properties of CD8 + CD28T cells in atopic and non-atopic individuals. METHODS Peripheral blood mononuclear cells (PBMC) were obtained after density gradient centrifugation. CD8 + CD28 and CD8 + CD28 + T cells were isolated using immunomagnetic beads. Relative percentages of these cells and expression of several phenotypic markers were analyzed by flow cytometry. Proliferation was assessed by thymidine incorporation in isolated populations and in co-cultures with PBMC using Dermatophagoides pteronyssinus as stimulus. Cytokine synthesis was evaluated in culture supernatants by cytometric bead array. RESULTS The relative percentages of CD8+CD28 T cells and their phenotypic expression in atopic and non-atopic volunteers were not significantly different. However, CD8 + CD28 T cells showed greater proliferation than did CD8+CD28+ T cells when stimulated with D. pteronyssinus, although cytokine synthesis patterns were similar. CD8+CD28 co-cultures with PBMC showed greater proliferation than CD8+CD28+ T cell co-cultures, but cytokine synthesis patterns were not different. CONCLUSIONS Our data confirm phenotypic and functional differences between CD28+ and CD28 T cells, irrespective of atopic status. Purified human CD8+CD28 T cells, freshly isolated from peripheral blood, do not have suppressor properties on allergen-specific proliferation or on cytokine synthesis in PBMC.

Obstructive pulmonary disease in patients with previous tuberculosis : pathophysiology of a community-based cohort

BACKGROUND An association between chronic airflow limitation (CAL) and a history of pulmonary tuberculosis (PTB) has been confirmed in epidemiological studies, but the mechanisms responsible for this association are unclear. It is debated whether CAL in this context should be viewed as chronic obstructive pulmonary disease (COPD) or a separate phenotype. OBJECTIVE To compare lung physiology and high-resolution computed tomography (HRCT) findings in subjects with CAL and evidence of previous (healed) PTB with those in subjects with smoking-related COPD without evidence of previous PTB. METHODS Subjects with CAL identified during a Burden of Obstructive Lung Disease (BOLD) study performed in South Africa were studied. Investigations included questionnaires, lung physiology (spirometry, body plethysmography and diffusing capacity) and quantitative HRCT scans to assess bronchial anatomy and the presence of emphysema (<-950 HU), gas trapping (<-860 HU) and fibrosis (>-200 HU). Findings in subjects with a past history and/or HRCT evidence of PTB were compared with those in subjects without these features. RESULTS One hundred and seven of 196 eligible subjects (54.6%) were enrolled, 104 performed physiology tests and 94 had an HRCT scan. Based on history and HRCT findings, subjects were categorised as no previous PTB (NPTB, n=31), probable previous PTB (n=33) or definite previous PTB (DPTB, n=39). Subjects with DPTB had a lower diffusing capacity (Δ=-17.7%; p=0.001) and inspiratory capacity (Δ=-21.5%; p=0.001) than NPTB subjects, and higher gas-trapping and fibrosis but not emphysema scores (Δ=+6.2% (p=0.021), +0.36% (p=0.017) and +3.5% (p=0.098), respectively). CONCLUSIONS The mechanisms of CAL associated with previous PTB appear to differ from those in the more common smoking-related COPD and warrant further study.