Percorrer por autor "Almeida, Isabel"
A mostrar 1 - 2 de 2
Resultados por página
Opções de ordenação
- The Protective Role of HLA-DRB1(*)13 in Autoimmune DiseasesPublication . Bettencourt, Andreia; Carvalho, Cláudia; Leal, Bárbara; Brás, Sandra; Lopes, Dina; Martins da Silva, Ana; Santos, Ernestina; Torres, Tiago; Almeida, Isabel; Farinha, Fátima; Barbosa, Paulo; Marinho, António; Selores, Manuela; Correia, João; Vasconcelos, Carlos; Costa, Paulo P.; da Silva, Berta MartinsAutoimmune diseases (AIDs) are characterized by a multifactorial aetiology and a complex genetic background, with the MHC region playing a major role. We genotyped for HLA-DRB1 locus 1228 patients with AIDs-213 with Systemic Lupus Erythematosus (SLE), 166 with Psoriasis or Psoriatic Arthritis (Ps + PsA), 153 with Rheumatoid Arthritis (RA), 67 with Systemic Sclerosis (SSc), 536 with Multiple Sclerosis (MS), and 93 with Myasthenia Gravis (MG) and 282 unrelated controls. We confirmed previously established associations of HLA-DRB1(∗)15 (OR = 2.17) and HLA-DRB1(∗)03 (OR = 1.81) alleles with MS, HLA-DRB1(∗)03 with SLE (OR = 2.49), HLA-DRB1(∗)01 (OR = 1.79) and HLA-DRB1(∗)04 (OR = 2.81) with RA, HLA-DRB1(∗)07 with Ps + PsA (OR = 1.79), HLA-DRB1(∗)01 (OR = 2.28) and HLA-DRB1(∗)08 (OR = 3.01) with SSc, and HLA-DRB1(∗)03 with MG (OR = 2.98). We further observed a consistent negative association of HLA-DRB1(∗)13 allele with SLE, Ps + PsA, RA, and SSc (18.3%, 19.3%, 16.3%, and 11.9%, resp., versus 29.8% in controls). HLA-DRB1(∗)13 frequency in the AIDs group was 20.0% (OR = 0.58). Although different alleles were associated with particular AIDs, the same allele, HLA-DRB1(∗)13, was underrepresented in all of the six diseases analysed. This observation suggests that this allele may confer protection for AIDs, particularly for systemic and rheumatic disease. The protective effect of HLA-DRB1(∗)13 could be explained by a more proficient antigen presentation by these molecules, favouring efficient clonal deletion during thymic selection.
- Vitamin D supplementation effects on FoxP3 expression in T cells and FoxP3+/IL-17A ratio and clinical course in systemic lupus erythematosus patients: a study in a Portuguese cohortPublication . Marinho, António; Carvalho, Cláudia; Boleixa, Daniela; Bettencourt, Andreia; Leal, Bárbara; Guimarães, Judite; Neves, Esmeralda; Oliveira, José Carlos; Almeida, Isabel; Farinha, Fátima; Costa, Paulo P.; Vasconcelos, Carlos; Silva, Berta M.Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multi-organ inflammation, linked to loss of immune tolerance to self-antigens and the production of a diversity of autoantibodies, with a negative impact on the patients' quality of life. Regulatory T cells have been reported as deficient in number and function in SLE patients. However, some authors also described an enrichment of this cell type. The hypothesis that certain forms of autoimmunity may result from a conversion of Treg cells into a Th17 cell phenotype has been suggested by some studies. In fact, in SLE patients' sera, the IL-17 levels were observed as abnormally high when compared with healthy individuals. Environmental factors, such as vitamin D, that is considered a potential anti-inflammatory agent, combined with genetic and hormonal characteristics have been associated with SLE phenotype and with disease progression. The aim of this study was to evaluate the effect of vitamin D supplementation on FoxP3 expression and IL-17A-producing T cells, through FoxP3+/IL-17A ratio. Additionally, disease evolution, serum vitamin D levels, serum autoantibodies levels and calcium metabolism (to assure safety) were also studied. We assessed 24 phenotypically well-characterized SLE patients. All patients were screened before vitamin D supplementation and 3 and 6 months after the beginning of this treatment. Peripheral blood lymphocyte's subsets were analysed by flow cytometry. Serum 25(OH)D levels significantly increased under vitamin D supplementation (p = 0.001). The FoxP3+/IL-17A ratio in SLE patients after 6 months of vitamin D supplementation was higher than that in the baseline (p < 0.001). In conclusion, this study demonstrated that vitamin D supplementation provided favourable, immunological and clinical impact on SLE.