The diverse roles of T cell subsets in asthma

• Autor(a) principal: Regateiro, F.S.
• Data de Publicação: 2021
• Outros Autores: Botelho Alves, P., Moura, A.L., Azevedo, J.P., Regateiro, Frederico S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/17166
• topic: Asthma; T cells; Regulatory T cells; Asthma endotypes; Asthma biomarkers

Asthma is a heterogeneous disease. Several distinct clinical phenotypes have been described and it is now debated whether asthma is a “single disease” or, instead, a group of inflammatory lung diseases with similar manifestations but diverse pathophysiology. More recently, these underlying inflammation mechanisms have been used to classify asthma into “endotypes” (1). Although several markers have been proposed to distinguish specific asthma endotypes (e.g., IgE sensitization in allergic asthma, peripheral eosinophil counts in eosinophilic asthma, periostin in Th2-high asthma, etc.), the most consensual distinction is based on the CD4+ T-helper (Th) cytokine profiles involved (i.e., Th2-high vs Th2-low), therefore illustrating the central role of these cells in asthma. T cells are central coordinators of the immune response. T-cell receptor (TCR) recognition is crucial for the initiation and specificity of the adaptive immune response, while T cell dervied cytokines tailor the type of immune response. Asthma is an inflammatory lung disease and T cells have been shown to play a central role in the pathophysiology of the disease. A good understanding of T cells in asthma is also important for therapeutic reasons, in particular for the choice of biological treatments in severe asthma. T cells are generally divided into two major types: CD4+ T cells and CD8+ T cells. CD4+ T cell are activated by antigen presented by major histocompatibility complex (MHC) class II on the surface of professional antigen-presenting cells (APC), whereas CD8+T cells recognize antigens presented by MHC class I on the surface of all nucleated cells. As discussed below, each of these types can be subdivided into several functionally distinct subtypes. Classically, asthma has been considered a Th2-mediated inflam matory disease. However, more recent studies have identified contributing roles for other types of T cells in the pathophysiology and the heterogeneity of the disease. In this chapter, we review how the different types and subtypes of T cells are involved in asthma and its phenotypes/endotypes.