G Loureiro

University of Coimbra, Coímbra, Coimbra, Portugal

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Publications (35)48.5 Total impact

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    Full-text · Chapter · Apr 2015
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    ABSTRACT: Here we evaluated whether allergic rhinitis to Dermatophagoides pteronyssinus induces alterations on circulating B cell subsets. Circulating B cell subsets and isotype expression on antigen-experienced B cells from allergic patients under conventional pharmacological treatment (NO-SIT, n = 15) and under subcutaneous immunotherapy (SCIT, n = 33), and non-allergic subjects (NC, n = 25) were analyzed by flow cytometry. In allergic patients, we found a significant decrease in IgM(+) and IgG(+) memory B cells and an increase in IgA(+) memory B cells. Additionally, the numbers of circulating IgA(+) plasmablasts in allergic patients were also increased, while those cells expressing IgM were reduced. Allergic patients have a disturbed B cell subsets distribution which seems to underlie rhinitis pathogenesis and remain unchanged after SCIT.
    Full-text · Article · Feb 2015 · Inflammation Research
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    ABSTRACT: Background Basophils are important effectors cells in allergic rhinitis (AR) since they are involved in immunoglobulin (Ig) E – mediated inflammation and in the release of pro-inflammatory mediators. Specific subcutaneous immunotherapy (SCIT) provides clear immunologic modulation in some immune cells, however its systemic effects on basophils are not well known. Methods Peripheral blood (PB) samples from 43 patients with allergic rhinitis mono-sensitized to Dermatophagoides pteronyssinus (Dpt) [33 of them under SCIT with allergoid Dpt extract, in maintenance dose (SCIT), with evaluation just before SCIT injection (SCIT-T0) and 4 hours later (SCIT-T4) and the other 10 Dpt allergic patients never having, in the past, undergone specific immunotherapy treatment (NSIT)], and 15 healthy age- and gender-matched controls (HG), were analyzed. For each sample, the total (t-IgE) and specific IgE (s-IgE) was performed, as well as, the relative frequency and absolute number of PB basophils and receptor-bound IgE and IgG expression were evaluated by flow cytometry and the Histamine N-methyltransferase (HNMT) and tryptase α/β1 (TPSAB1) gene expression was assessed by real-time PCR. Results Higher levels of receptor-bound IgE were observed in SCIT patients, which are correlated with the levels of serum t-IgE and s-IgE, whereas no significant differences were observed for receptor-bound IgG. Regarding HNMT mRNA expression, significantly lower expression levels were detected in AR patients compared to HG, independently of type of therapy. Moreover a negative correlation was found between HNMT gene expression and time under SCIT. Conversely, tryptase gene expression was significantly up-regulated in NSIT when compared to HG; however in SCIT patients, tryptase gene expression was significantly decreased than in NSIT patients. No differences were found for any parameter between SCIT-T0 and SCIT-T4 with exception of a transient increased expression of tryptase in SCIT-T4. Conclusion PB basophils from patients with AR show altered functional features, which seems to be influenced by SCIT, suggesting that these cells could be useful to clarify the SCIT triggered mechanisms at a systemic level.
    Full-text · Article · Oct 2013 · Allergy Asthma and Clinical Immunology
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    ABSTRACT: T cell receptor excision circles (TREC) on CD31+ T cells are related to recent thymic emigrant cells (RTEs). The involvement of the functional thymic tissue occurs early in the IgE-mediated allergic reaction, and in response to specific immunotherapy (SIT). Evaluation of specific immunotherapy effects on TREC number in peripheral T cells in patients allergic to Dermatophagoides pteronyssinus (Dpt). 85 respiratory allergic patients (both genders), 41 of them (Group II) under maintenance treatment to Dpt SIT (21 sublingual-SLIT, and 20 subcutaneous-SCIT), were selected. The allergic patients (Group I) without specific treatment were submitted to an allergen challenge test (22 nasal and 22 conjunctival). Peripheral cell analysis was performed immediately before treatment and 60 or 240 minutes after allergenic extract administration. TREC quantification was performed in CD4+CD31+ and CD8+CD31+. The results were expressed per 100.000 cells related to RTEs. Samples from 10 healthy individuals (Control - Group III) were obtained with the same method. The value of TRECs on RTEs was constant in control groups. For Group I patients (nasal or conjunctival test), TREC quantification in CD31+ T cells showed relevant individual changes, even in the patients tested earlier (60 minutes), and statistical significant at 240 minutes. Both SCIT and SLIT had also demonstrated enormous individual changes, particularly on TRECs/CD4+CD31+ cells assay. Basal values in Group III were significantly higher than those observed in active patients groups. Thymic functional activity is earlier involved in the allergic reaction and SIT IgE-mediated allergy is able to induce RTEs in the periphery, particularly TRECs/CD4+CD31+ cells. Both SLIT and SCIT showed reduced RETs in the periphery, probably due to maturation of regulatory T cells. Our results suggest a crucial role of the functional thymic tissue on the central mechanism of this therapy.
    Full-text · Article · Apr 2012 · European annals of allergy and clinical immunology
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    D Machado · C Pereira · B Tavares · G Loureiro · A Segorbe-Luís
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    ABSTRACT: Inhaled combined therapy improves the pulmonary function in asthmatic patients. The effect on the airway hyperresponsiveness (AHR) and the efficacy of different pharmacological schedules is not well clarified on adolescent asthmatics. Evaluate the responses to different combined inhaled therapies in adolescent asthmatics and study its impact on exercise induced AHR. Basal lung function tests (LFT) were performed in 30 adolescents (13 to 16 years old; 19 female) with allergic asthma. They were submitted to exercise challenge test (EC) followed by bronchodilator test (BD). During 4 weeks, 15 adolescents were submitted to inhaled fluticasone/salmeterol (group A) and other 15 to inhaled budesonide/formoterol (group B). After this period, they underwent another functional evaluation as previous. Before treatment, pulmonary function was similar in both groups. After 4 weeks of treatment, these groups showed an improvement of the basal LFT (p = 0.001 for FEV1 in both), decrease on bronchoconstriction induced by exercise (NS for both) and less recovery on BD response (p = 0.001 and 0.002, for FEV1 respectively groups A and B). Group B showed a better performance, with higher improvement of basal FEF 25/75 (p = 0.001), reduced bronchoconstriction response to EC (p = 0.008 for FEV1) and fewer response to BD test (p < 0.0001 for FEV1 and 0.024 for FEF 25/75) No adverse events were observed. After 4 weeks of inhaled combined therapy, these patients improved their pulmonary function and bronchomotricity. Those under budesonide/formoterol showed the highest improvement. These medications are a safe measure in controlling the asthma in these patients.
    Full-text · Article · Feb 2012 · European annals of allergy and clinical immunology
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    ABSTRACT: Introduction: T cell receptor excision circles (TRECs) on CD31+ T cells are related to recent thymic emigrant cells (RTEs). Aim: Evaluation of specific immunotherapy effects on number of TREC in peripheral T cells in patients allergic to Dermatophagoides pteronyssinus (Dpt). Method: 85 respiratory allergic patients (both genders), 41 (Group II) under maintenance treatment to Dpt SIT (21 sublingual, SLIT, and 20 subcutaneous, SCIT), were selected. The allergic patients (Group I) without specific treatment underwent an allergen challenge test (22 nasal and 22 conjunctival). Peripheral cell analysis was performed immediately before treatment and 60 or 240 minutes after allergenic extract administration. TREC count was performed in CD4+CD31+ and CD8+CD31+ cells. The results were expressed per 100,000 RTE-related cells. Samples from 10 healthy individuals (Control - Group III) were obtained using the same method. Results: The value of TRECs on RTEs was constant in control groups. Group I patients' TREC count in CD31+-T cells showed relevant individual changes, even in the patients tested earlier (60 minutes), and statistical significant at 240 minutes. Both SCIT and SLIT also demonstrated enormous individual changes, particularly on TRECs/CD4+CD31+ cell assay. Basal values in Group III were significantly higher than those observed in active patient groups. Conclusions: Thymic functional activity has early involvement in the allergic reaction and SIT. IgEmediated allergy is able to induce RTEs in the periphery, particularly TRECs/CD4+CD31+ cells. Both SLIT and SCIT showed reduced RETs in the periphery, probably due to maturation of regulatory T cells. Our results suggest a crucial role of the functional thymic tissue in the central mechanism of this therapy.
    No preview · Article · Jan 2012 · Revista Portuguesa de Imunoalergologia
  • G. Calado · G. Loureiro
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    ABSTRACT: Stress is recognized as an important factor of exacerbation, worsening and lack of treatment response in several allergic diseases, namely in conjunctivitis, rhinitis, asthma and atopic dermatitis. However, its etiopathogenic mechanisms are still poorly understood. In this article, the potential mechanisms responsible by the impact of stress in allergic disease are reviewed, addressing the role of the neuroendocrine system and its interactions with the immune system, the interference with the oxidative pathway, the impact of corticoresistance and the importance of genetic factors.
    No preview · Article · Jan 2012 · Revista Portuguesa de Imunoalergologia
  • Gisela Calado · Graça Loureiro
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    ABSTRACT: Stress is recognized as an important factor of exacerbation, worsening and lack of treatment response in several allergic diseases, namely in conjunctivitis, rhinitis, asthma and atopic dermatitis. However, its etiopathogenic mechanisms are still poorly understood. In this article, the potential mechanisms responsible by the impact of stress in allergic disease are reviewed, addressing the role of the neuroendocrine system and its interactions with the immune system, the interference with the oxidative pathway, the impact of corticoresistance and the importance of genetic factors.
    No preview · Article · Jan 2012 · Revista Portuguesa de Imunoalergologia
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    ABSTRACT: Introduction: T cell receptor excision circles (TRECs) on CD31+ T cells are related to recent thymic emigrant cells (RTEs).
    No preview · Article · Jan 2012 · Revista Portuguesa de Imunoalergologia
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    G Calado · G Loureiro · D Machado · B Tavares · C Ribeiro · C Pereira · A.S. Luís
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    ABSTRACT: BACKGROUND: The primary role of infections in chronic urticaria (CU) is controversial. We hypothesised that streptococcal tonsillitis (ST) could be a primary cause of CU or acute recurrent urticaria (ARU). METHODS: Retrospective study of 14 outpatients observed between January 2000 and December 2009, with CU/ARU and clinical and/or laboratorial suspicion of an aetiopathogenic link with ST. Clinical history, objective examination and laboratorial study were looked for. Three groups were defined: spontaneous resolution of urticaria, resolution after tonsillectomy, and still symptomatic. RESULTS: In these patients, a causal relationship between ST and urticaria is supported by: markers of streptococcal infection, the perception of a clinical relationship between tonsillitis and urticaria, the decrease of urticaria severity with early antibiotherapy to tonsillitis and urticaria resolution after tonsillectomy. CONCLUSIONS: Our study encourages the investigation of tonsillitis in these otherwise idiopathic patients, especially until young adulthood and even in the absence of any symptoms.
    Full-text · Article · Oct 2011 · Allergologia et Immunopathologia
  • G Calado · D Machado · C Ribeiro · G Loureiro · B Tavares · C Pereira · R Cunha · C Chieira

    No preview · Article · Jul 2011 · Allergologia et Immunopathologia
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    Full-text · Conference Paper · Jan 2011
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    D Machado · G Loureiro · B Tavares · G Calado · C Pereira

    Full-text · Article · Jan 2011 · Journal of investigational allergology & clinical immunology: official organ of the International Association of Asthmology (INTERASMA) and Sociedad Latinoamericana de Alergia e Inmunología

  • No preview · Article · Jun 2010 · Allergy
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    ABSTRACT: High-resolution computed tomography (HRCT) is a widespread medical imaging method for the study of thoracic diseases. In asthma it is very useful particularly when it is difficult to achieve an effective control of disease, and in severe deterioration. It was intended to evaluate the imaging changes by HRCT in asthmatic patients and to assess the expression according to the symptoms and duration of disease. Thirty three patients from the Outpatient Department, with asthma classified in the different clinical severity stages according to GINA, were randomly included. They were submitted to HRCT (Somaton Plus-4, Siemens). The lesions were classified in reversible (mucoid impaction, acinar pattern centrilobular nodules and lobar collapse) and irreversible (bronchiectasis, bronchial wall-thickening, sequellar line shadows and emphysema). The 33 asthmatic patients (20 female) had an average age of 44.76 +/- 16.98 years and a mean disease evolution time of 23.39 +/-14.83 years. 30% had mild persistent asthma, 43% moderate persistent asthma and 27% severe persistent asthma. All the patients were under inhaled corticotherapy. Only 6 patients had normal HRCT 4 with mild persistent asthma (4 to 25 years of duration of disease) and 2 with moderate persistent (10 to 48 years of duration of disease). 81.81% of the patients had changes in HRCT, being the irreversible lesions the most frequent. The most important irreversible lesions were observed in severe asthma patients with longer duration of disease. All the patients with reversible lesions had also irreversible changes. Most of the bronchiectasis were centrally located and were found in severe asthma patients. Irreversible changes were identified in 3 patients with mild asthma and a maximum of 6 years of duration of disease. HRCT findings were related with asthma severity and long lasting disease but there are some asthmatics that also present early abnormalities, even in milder forms. All the groups of asthmatic patients presented all types of imaging changes, including the irreversible ones. In asthma these changes can be the result of individual patterns of response to frequent exacerbations, leading to a persistent chronic inflammatory process that will determine airway remodelling, even in early stages of disease and/or mild asthma.
    No preview · Article · Oct 2009 · European annals of allergy and clinical immunology
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    ABSTRACT: Food allergy is an increasing problem with limited therapeutic approaches apart from to the eviction diet. A 40-year-old female patient with food allergy symptoms was polysensitized to almost all vegetable food since the age of 36; the onset of symptoms was during pregnancy. The allergological study demonstrated positive skin prick tests (SPT) to nuts, legumes, cereals, spices, several fresh fruits including peach, and other groups of vegetable foods however, it was negative to common aeroallergens. Serum specific IgE levels were negative (<0.35 kU/L) to profilin and carbohydrate determinants, but positive to Pru p 3 (3.5 kU/L). Positive double-blind placebo-controlled food challenge to peach confirmed the allergic disease. She received specific sublingual immunotherapy with native Pru p 3 at a concentration of 40 mug/ml with 5 administrations per week and a cumulative dose of 200 mug of nPru p 3 per month. After an ultra-rush build-up phase concluded in one day she continued therapy during a year with 5 administrations per week. The clinical evolution and laboratory studies demonstrated an early reduction on SPT reactions with no relevant changes on serum specific IgE, IgG, IgG(1) and IgG(4) to Pru p 3 during the immunotherapy period. The challenge test was negative 4 months after the beginning of the SLIT. Regarding clinical response she markedly improved after the first month of treatment, and by the 3th month she had no major vegetable dietary restrictions, except for nuts and pepper. These results demonstrate the excellent efficacy and safety of sublingual specific protein immunotherapy developed according to the patient specific sensitivity profile to Pru p3.
    Full-text · Article · May 2009 · Cases Journal
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    ABSTRACT: Background: Occupational respiratory diseases are common in some sectors of the textile industry. The environmental airborne particles can induce sensitisation, worsen preexisting allergic pathology or trigger work -related clinical exacerbations. Objective: To show the relationship between respiratory symptoms and textile industry occupational exposure using the specifi c inhalation challenge test (SIC) in a challenge chamber. Subjects: Twelve female textile spinners, mean age 41.5±8.44 years with work -related respiratory symptoms. Methodology: Patients underwent a clinical evaluation, skin prick tests (SPT) to aeroallergens cotton, wool and kapok, basal lung function study, serial peak expiratory fl ow (PEF) rate (in and out of the workplace) and SIC performed by bronchial exposure to textile material with clinical and functional monitoring for four hours. Results: Mean work years was 24.1±8.62 years and duration of symptoms 6.55±9.07 years. Ten workers complained of rhinitis, 10 of bronchial respiratory symptoms and seven of conjunctivitis symptoms. All patients had negative SPT to textile allergens, three patients were sensitised to aeroallergens. Basal lung function was normal in all patients. None of the workers performed serial PEF correctly. The SIC was positive in 10 workers. Discussion: Occupational disease was confi rmed in 10 workers. SIC with challenge chamber is a very important diagnostic procedure in the study of respiratory disease in textile industry
    Full-text · Article · May 2009 · Revista Portuguesa de Imunoalergologia
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    ABSTRACT: Dermatophytosis is frequent in the general population, but induction of specifi c allergic sensitisation is unusual and controversial. We present two case reports of patients with chronic urticaria (female, 49 years old; male, 55 years old). Prior to this, they had dermatophytosis lesions in the extremities that required frequent topical and systemic anti -fungal treatment cycles for 1 and 7 years, respectively. In both patients, urticaria was more intense during fungal infection fl are-ups. The allergology study showed positive skin (prick and intradermal) tests (STs) to Trichophyton mentagrophytes (Tm) and positive serum specific IgE to Trichophyton rubrum (Tr) (4.1kU/L and 1.89kU/L). The patients underwent subcutaneous specific immunotherapy (SCIT) to Tm, with progressive improvement of urticaria and complete resolution of the dermatophytosis lesions. In these two patients, SCIT demonstrated high clinical effi cacy, and it was able to modify the skin reactivity and reduce serumspecific IgE to Tr.
    Full-text · Article · Mar 2009 · Revista Portuguesa de Imunoalergologia
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    G Loureiro · B Tavares · C Pereira · M Lundberg · C Chieira

    Full-text · Article · Feb 2009 · Journal of investigational allergology & clinical immunology: official organ of the International Association of Asthmology (INTERASMA) and Sociedad Latinoamericana de Alergia e Inmunología
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    ABSTRACT: CD86 is a well-known costimulatory molecule in its interaction with CD28 and/or CTLA present on T cells, and is essential for full activation of naïve T-cell and subsequent differentiation. Usually the B7 molecules are expressed mainly on APCs and B cells and in specific conditions on other activated cells. These costimulatory molecules are involved in the development of allergic inflammation and airways hyperreactivity (AHR) in allergen-challenged mice. Activated T cells, CD4(+)CD25(+), express CD86 in the first 60 minutes after the specific inhalatory exposure. These T cells can be relevant in IgE mediated allergic reaction possibly by an autocrine costimulation via CD28/CTLA activation pathway. The blockage of the expression of CD86 could be a potential therapeutical target to reduce the magnitude or the progression of the allergic reaction. The review article also discussed relevant patents.
    No preview · Article · Feb 2009 · Recent Patents on Inflammation & Allergy Drug Discovery