BACKGROUND: Omenn syndrome (OS) is characterized by a peculiar severe T-cell immune deficiency associated with autoimmunelike manifestations. Dysregulations of the central and peripheral immune tolerance, mediated by the protein autoimmune regulator (AIRE) and regulatory T cells, respectively, were proposed as possible mechanisms of this aberrant inflammatory process. OBJECTIVE: We studied mechanisms of central and peripheral tolerance in patients with OS and also examined the gene expression profile associated with OS features. METHODS: T-cell receptor diversity, DNA rearrangement, and the expression of AIRE and forkhead box P3 mRNA as well as the expression of regulatory T cells in cells obtained from patients with OS were studied. Characterization of gene expression in these cells was carried out by using the TaqMan Low-Density Array. RESULTS: Transcript expression of peripheral blood AIRE but not forkhead box P3 was reduced in patients with OS. The expression of natural killer T and regulatory T cells was normal, although the latter showed an abnormal CD4-negative population. Patients with OS have oligoclonal T cells with limited DNA recombination activity, including the presence of early but not late T-cell maturation events, regardless of the genetic defect underlying the syndrome. The transcriptional profile associated with OS features reveals significant changes in 25.5% of the tested genes compared with normal control. CONCLUSION: Our findings suggest that T-cell oligoclonal expansion in OS emanates from an incomplete block before the maturation stage of negative selection, which may explain escape of autoreactive T cells from the thymus. Dysregulated genes in patients with OS are closely involved with self-tolerance and autoimmunity.
BACKGROUND:Omenn syndrome (OS) is characterized by a peculiar severe T-cell immune deficiency associated with autoimmunelike manifestations. Dysregulations of the central and peripheral immune tolerance, mediated by the protein autoimmune regulator (AIRE) and regulatory T cells, respectively, were proposed as possible mechanisms of this aberrant inflammatory process. OBJECTIVE: We studied mechanisms of central and peripheral tolerance in patients with OS and also examined the gene expression profile associated with OS features. METHODS: T-cell receptor diversity, DNA rearrangement, and the expression of AIRE and forkhead box P3 mRNA as well as the expression of regulatory T cells in cells obtained from patients with OS were studied. Characterization of gene expression in these cells was carried out by using the TaqMan Low-Density Array. RESULTS: Transcript expression of peripheral blood AIRE but not forkhead box P3 was reduced in patients with OS. The expression of natural killer T and regulatory T cells was normal, although the latter showed an abnormal CD4-negative population. Patients with OS have oligoclonal T cells with limited DNA recombination activity, including the presence of early but not late T-cell maturation events, regardless of the genetic defect underlying the syndrome. The transcriptional profile associated with OS features reveals significant changes in 25.5% of the tested genes compared with normal control. CONCLUSION: Our findings suggest that T-cell oligoclonal expansion in OS emanates from an incomplete block before the maturation stage of negative selection, which may explain escape of autoreactive T cells from the thymus. Dysregulated genes in patients with OS are closely involved with self-tolerance and autoimmunity.
Authors: Suk See De Ravin; Edward W Cowen; Kol A Zarember; Narda L Whiting-Theobald; Douglas B Kuhns; Netanya G Sandler; Daniel C Douek; Stefania Pittaluga; Pietro L Poliani; Yu Nee Lee; Luigi D Notarangelo; Lei Wang; Frederick W Alt; Elizabeth M Kang; Joshua D Milner; Julie E Niemela; Mary Fontana-Penn; Sara H Sinal; Harry L Malech Journal: Blood Date: 2010-05-20 Impact factor: 22.113
Authors: A Lev; A J Simon; J Ben-Ari; D Takagi; T Stauber; L Trakhtenbrot; E Rosenthal; G Rechavi; N Amariglio; R Somech Journal: Clin Exp Immunol Date: 2014-06 Impact factor: 4.330