SAMAR FRESCHI DE BARROS

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6
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Unidades Organizacionais
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina
LIM/19 - Laboratório de Histocompatibilidade e Imunidade Celular, Hospital das Clínicas, Faculdade de Medicina

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  • article 6 Citação(ões) na Scopus
    Thymopoiesis in Pre- and Post-Hematopoietic Stem Cell Transplantation
    (2018) ROCHA, Luis Klaus A. da; BARROS, Samar Freschi de; BANDEIRA, Francine; BOLLINI, Alexia; TESTA, Lucia Helena de A.; SIMIONE, Anderson Joao; SOUZA, Marina de O. e; ZANETTI, Lilian P.; OLIVEIRA, Leila Cibele S. de; SANTOS, Ana Claudia F. dos; SOUZA, Mair Pedro de; COLTURADO, Vergilio Antonio R.; KALIL, Jorge; MACHADO, Clarisse M.; GUILHERME, Luiza
    Hematopoietic stem cell transplantation (HSCT) is an important therapeutic option for some hematological diseases. However, patients who undergo HSCT acquire a state of immunodeficiency that causes significant mortality. Reconstitution of thymic function is needed to support the immune system. One way to measure thymic function is through T-cell receptor excision circle (TREC) quantification. TRECs are generated by T-cell receptor gene rearrangements during T-cell maturation in the thymus and represent a reliable marker for thymic output. In this study, we aimed to assess aging and malignant hematological diseases as two important factors that may influence thymic output before HSCT. We observed that patients before HSCT presented signal joint TREC (sjTREC) numbers lower than 606.55 copies/mu g DNA (low values) compared with healthy individuals, with an odds ratio (OR) of 12.88 [95% confidence interval (CI): 5.26-31.53; p < 0.001]. Our results showed that a group of older individuals (>= 50 years old), comprising both healthy individuals and patients, had an OR of 10.07 (95% CI: 2.80-36.20) for low sjTREC values compared with younger individuals (<= 24 years old; p < 0.001). Multiple logistic regression analysis confirmed that both older age (>= 50 years old) and malignant hematological diseases and their treatments were important and independent risk factors related to thymic function impairment (p < 0.001). The median sjTREC value for patients of all ages was significantly lower than the sjTREC median for the subgroup of older healthy individuals (>= 50 years old; p < 0.001). These data suggested that patients before HSCT and healthy individuals exhibited age-dependent thymic impairment, and that prior treatment for hematological diseases may exacerbate aging-related deterioration of natural thymic function. Furthermore, we analyzed these patients 9 months post-HSCT and compared patients who underwent autologous HSCT with those who underwent allogeneic HSCT. Both groups of patients achieved sjTREC copy numbers similar to those of healthy individuals. We did not find a close relationship between impaired thymic function prior to HSCT and worse thymic recovery after HSCT.
  • article 0 Citação(ões) na Scopus
    A brazilian nationwide multicenter study on deficiency of deaminase-2 (DADA2)
    (2023) MELO, Adriana; CARVALHO, Luciana Martins de; FERRIANI, Virginia Paes Leme; CAVALCANTI, Andre; APPENZELLER, Simone; OLIVEIRA, Valeria Rossato; NETO, Herberto Chong; ROSARIO, Nelson Augusto; POSWAR, Fabiano de Oliveira; GUIMARAES, Matheus Xavier; KOKRON, Cristina Maria; MAIA, Rayana Elias; SILVA, Guilherme Diogo; KELLER, Gabriel; FERREIRA, Mauricio Domingues; VASCONCELOS, Dewton Moraes; TOLEDO-BARROS, Myrthes Anna Maragna; BARROS, Samar Freschi; NETO, Nilton Salles Rosa; KRIEGER, Marta Helena; KALIL, Jorge; MENDONCA, Leonardo Oliveira
    IntroductionThe deficiency of ADA2 (DADA2) is a rare autoinflammatory disease provoked by mutations in the ADA2 gene inherited in a recessive fashion. Up to this moment there is no consensus for the treatment of DADA2 and anti-TNF is the therapy of choice for chronic management whereas bone marrow transplantation is considered for refractory or severe phenotypes. Data from Brazil is scarce and this multicentric study reports 18 patients with DADA2 from Brazil.Patients and methodsThis is a multicentric study proposed by the Center for Rare and Immunological Disorders of the Hospital 9 de Julho - DASA, Sao Paulo - Brazil. Patients of any age with a confirmed diagnosis of DADA2 were eligible for this project and data on clinical, laboratory, genetics and treatment were collected.ResultsEighteen patients from 10 different centers are reported here. All patients had disease onset at the pediatric age (median of 5 years) and most of them from the state of Sao Paulo. Vasculopathy with recurrent stroke was the most common phenotype but atypical phenotypes compatible with ALPS-like and Common Variable Immunodeficiency (CVID) was also found. All patients carried pathogenic mutations in the ADA2 gene. Acute management of vasculitis was not satisfactory with steroids in many patients and all those who used anti-TNF had favorable responses.ConclusionThe low number of patients diagnosed with DADA2 in Brazil reinforces the need for disease awareness for this condition. Moreover, the absence of guidelines for diagnosis and management is also necessary (t).
  • article 0 Citação(ões) na Scopus
    Underlying IPEX syndrome in a patient with idiopathic juvenile arthritis and vitiligo
    (2022) MENDONCA, Leonardo Oliveira; CHUSTER, Adriana Pitchon dos Reis; DORNA, Mayra Barros; BARROS, Samar Freschi; ALVES, Janaina Baptista; GONCALVES, Victor Lucas; YANG, Ariana Campos; KALIL, Jorge; TOLEDO-BARROS, Myrthes Anna Maragna; KOKRON, Cristina Maria
    Background: IPEX syndrome is an X-linked inborn error of immunity clinically characterized by the triad of: enteropathy, polyendocrinopathy and eczema. However many other clinical presentations lacking the triad above described have been reported what underpin the need of careful clinical suspicion, immunological evaluation and genetic sequencing. Case presentation: Here we report a case of a Brazilian boy with severe eczema as the first and only presentation requiring cyclosporin therapy. Progressive and cumulative symptoms of arthritis and enteropathy lead to the suspicion of an inborn error of immunity. Peripheral FOXP3 expression was normal (CD127-/CD4+/CD25+/FOXP3+-396 cells-63%) and a pathogenic mutation in FOXP3 gene (c.1150G > A; p.Ala384Thr), confirmed the diagnosis of IPEX syndrome. Conclusions: IPEX syndrome should be suspected in patients presenting with severe eczema associated or not with other autoimmune/hyper inflammatory diseases in life. Our study also reinforces that FOXP3 expression by flowcytometry seems not to be a good screening method, and genetic sequencing is mandatory even in those with high suspicion and normal peripheral FOXP3 expression.