A carregar...
Projeto de investigação
Bolsa de Doutoramento FCT: Estudo funcional de células CD8+CD28- em voluntários atópicos e voluntários não atópicos [SFRH/BD/16448/2004]
Financiador
Autores
Publicações
Asthma is more frequently associated with non-allergic than allergic rhinitis in Portuguese patients
Publication . Lourenço, Olga; Fonseca, AM; Barata, Luis Taborda
Background: Rhinitis prevalence is increasing worldwide and is frequently associated with
asthma, for which it is a risk factor. The aims of the study were to characterise the adult population
with rhinitis attending the Cova da Beira Hospital Allergy Clinic, and to assess the relationship
between rhinitis and asthma.
Methods: In total, 686 patients were characterised by clinical history and anterior rhinoscopy,
and classified according to international guidelines. Atopy was determined by skin prick testing
to aeroallergens and quantification of specific IgE.
Results: Seventy two percent of patients had allergic rhinitis (AR), and 28% had non-allergic
rhinitis (NAR). NAR was more frequently associated with older age, perennial symptoms and
female gender. NAR patients more frequently had bronchial asthma. In addition, more NAR
than AR patients also had drug allergy, pharyngitis, sinusitis and urticaria. AR patients with
nasal polyps more frequently had asthma. Grass pollen and mites were the major sensitisers
for AR patients. Sensitisation profiles were not significantly different between urban- and ruralbased
AR patients.
Conclusions: Asthma was more frequently associated with non-allergic than with allergic rhinitis.
The two types of rhinitis did not differ in clinical severity. Although sensitisation profiles
were not different between the urban and rural patients, allergic rhinitis prevalence was higher
in urban patients.
Phenotypic and functional aspects of CD8 + T cells in atopy: from populations to cells
Publication . Lourenço, Olga Maria Marques; Barata, Luís Manuel Taborda; Arosa, Fernando Aguilar
The prevalence of allergic diseases has been increasing during the last decades. It is believed that the development of allergic diseases in susceptible individuals is dependent on T cells, especially type 2 CD4+ T cells. CD8+ T cells may also be involved in the pathophysiology of allergic diseases, albeit studies in animal models of asthma have found confounding results. With our study we attempted to clarify the phenotypic and functional properties of CD8+ T cells in allergic disease settings. The specific aims were to assess allergen-specific proliferation and cytokine synthesis of CD8+ T cells and evaluate their suppressor function on antigen-specific responses. In addition, it was also our goal to assess the presence of CD8+ T cells at the target organ and their activation status, correlating our findings with disease severity and control. In order to contextualize our cellular findings, we initially characterised our study population from an epidemiological point of view. We enrolled asthma and rhinitis patients attending the Allergy Clinic of the Cova da Beira Hospital. Asthma and rhinitis were diagnosed by a positive clinical history and specific diagnostic tests, and severity was assessed by current guidelines. We also identified the main co-morbidities in both disease settings and evaluated asthma symptoms in rhinitis patients and rhinitis symptoms in asthma patients. In the allergic groups we investigated the sensitisation profiles to aeroallergens and concluded that major allergens included grass and cereal pollen, mites and olive tree pollen. Sensitisation profiles and severity were also compared between rural and urban-based allergic patients. In this regard, we found contrasting results between asthmatic patients and patients with rhinitis. In the second part of our study we clarified the role of CD8+ T cells in allergic inflammation through basic cellular systems. We assessed proliferation capacity and cytokine synthesis in response to Dermatophagoides pteronyssinus extract, and devised a co-culture system in order to evaluate the suppressor function of CD8+ T cells. CD8+CD28+ and CD28− T cells isolated from the peripheral blood had distinct phenotypes and proliferated at different levels to common stimuli, although sharing similar cytokine production patterns. A potential suppressor activity was not found in the co-culture systems, either for CD8+CD28+ or CD28− T cells. We then studied CD8+ T cells at the target-organ, assessing activation phenotype in cells from the induced sputum of asthmatic patients. We showed that CD8+ T cells are activated at the target-organ, although we were unable to demonstrate a relationship between activation of this T cell subset and severity or control of asthma.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Bolsa de Doutoramento
Número da atribuição
SFRH/BD/16448/2004