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- Lipid Antigen Presentation by CD1b and CD1d in Lysosomal Storage Disease PatientsPublication . Pereira, C.; Pérez-Cabezas, B.; Ribeiro, H.; Maia, M.; Cardoso, M.; Dias, A.; Azevedo, O.; Ferreira, M.; Garcia, P.; Rodrigues, E.; Castro-Chaves, P.; Martins, Esmeralda; Aguiar, P.; Pineda, M.; Amraoui, Y.; Fecarotta, S.; Leão-Teles, E.; Deng, S.; Savage, P.; Macedo, M.The lysosome has a key role in the presentation of lipid antigens by CD1 molecules. While defects in lipid antigen presentation and in invariant Natural Killer T (iNKT) cell response were detected in several mouse models of lysosomal storage diseases (LSD), the impact of lysosomal engorgement in human lipid antigen presentation is poorly characterized. Here, we analyzed the capacity of monocyte-derived dendritic cells (Mo-DCs) from Fabry, Gaucher, Niemann Pick type C and Mucopolysaccharidosis type VI disease patients to present exogenous antigens to lipid-specific T cells. The CD1b- and CD1d-restricted presentation of lipid antigens by Mo-DCs revealed an ability of LSD patients to induce CD1-restricted T cell responses within the control range. Similarly, freshly isolated monocytes from Fabry and Gaucher disease patients had a normal ability to present α-Galactosylceramide (α-GalCer) antigen by CD1d. Gaucher disease patients' monocytes had an increased capacity to present α-Gal-(1-2)-αGalCer, an antigen that needs internalization and processing to become antigenic. In summary, our results show that Fabry, Gaucher, Niemann Pick type C, and Mucopolysaccharidosis type VI disease patients do not present a decreased capacity to present CD1d-restricted lipid antigens. These observations are in contrast to what was observed in mouse models of LSD. The percentage of total iNKT cells in the peripheral blood of these patients is also similar to control individuals. In addition, we show that the presentation of exogenous lipids that directly bind CD1b, the human CD1 isoform with an intracellular trafficking to the lysosome, is normal in these patients.
- Fatty Liver Caused by Glycogen Storage Disease Type IX: A Small Series of Cases in ChildrenPublication . Leuzinger Dias, C.; Maio, I.; Brandão, J.; Tomás, E.; Martins, Esmeralda; Santos Silva, E.Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) affecting children and adolescents has increased dramatically in recent years. This increase is most probably related to the obesity pandemic and the high consumption of fructose. However, hepatic steatosis has some rare causes (e.g., some metabolic diseases) of which clinicians should be aware, particularly (but not only) when patients are non-obese or non-overweight. Differential diagnosis is notably important when pathologies have a specific treatment, such as for glycogenosis type IX (GSD-IX). Aims: To contribute to the knowledge on the differential diagnosis of NAFLD in paediatric age and to the clinical, biochemical, molecular, and histological characterisations of GSD-IX, a rare metabolic disorder. Methods: We performed a retrospective study of a small series of cases (n = 3) of GSD-IX diagnosed in the past 6 years, who were currently being followed up in the Units of Gastroenterology or Metabolic Diseases of the Paediatric Division of our hospital and whose clinical presentation was NAFLD in paediatric age. Results: Three male patients were diagnosed with NAFLD before 2 years of age, 2 with confirmed diagnosis before the age of 3 years (alanine aminotransferase [ALT], liver ultrasound, and molecular analysis) and 1 whose diagnosis was confirmed at 11 years (ALT, liver ultrasound, liver histology, and molecular analysis). None of the patients were obese or overweight, and the daily fructose consumption was unknown. The outcome was favourable in all 3 patients, with follow-up periods ranging from 2 to 6 years. Conclusion: The decision on how far the search for secondary causes of NAFLD should go can be difficult, and GSD-IX must be on the list of possible causes.