Publications (6)25.77 Total impact
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Article: T and B cell deficiency associated with yellow nail syndrome.
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ABSTRACT: Yellow nail syndrome (YNS) is a rare disorder of unknown aetiology that is characterized by yellow nails associated with lymphoedema and chronic respiratory manifestations. There are no detailed immunological studies in YNS. In this study, we present first extensive immunological analysis of both adaptive and innate immunity in two patients with YNS. One patient has common variable immunodeficiency, whereas second patient has specific antibody deficiency syndrome. Severe lymphopaenia, a striking deficiency of naïve CD4+ and CD8+ T cells and total B cells, and increased transitional B cells were observed. T cell proliferative response to mitogens and antigens was significantly reduced in both patients. Both patients failed to make specific antibody response to pneumococci. Complement, natural killer cell activity and neutrophil oxidative burst were normal. Immunoglobulin administration resulted in decreased frequency and severity of infections, and an impressive effect was observed on lymphoedema and on the recurrence of pleural effusion. Our data show that YNS is associated with both T and B cell defects. Furthermore, Immunoglobulin may be beneficial in clinical manifestations of lymphoedema.Scandinavian Journal of Immunology 03/2012; 75(3):329-35. · 2.23 Impact Factor -
Article: Differential sensitivity of naïve and subsets of memory CD4+ and CD8+ T cells to hydrogen peroxide-induced apoptosis.
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ABSTRACT: CD4+ and CD8+ memory T cells are identified into central and effector memory subsets, which are characterized by distinct homing patterns and functions. In this investigation, we show that naïve and central memory CD4+ and CD8+ T cells are sensitive to hydrogen peroxide (H2O2)-induced apoptosis, whereas effector memory CD4+ and CD8+ T cells are relatively resistant to H2O2-induced apoptosis. Apoptosis in naïve and central memory CD4+ and CD8+ is associated with the release of cytochrome c and activation of caspase-9 and caspase-3, upregulation of Bax and voltage-dependent anion channel (VDAC) expression, and decreased intracellular glutathione (GSH). In vitro GSH and a superoxide dismutase mimetic Mn(III) tetrakis (1-methyl-4-pyridyl) porphyrin inhibited H2O2-induced apoptosis in both naïve and central memory CD4+ and CD8+ T cells. Furthermore, VDAC inhibitor 4,4'-diisothiocynostilbene-2,2'-disulfonic acid blocked H2O2-induced apoptosis. These data demonstrate that H2O2 induces apoptosis preferentially in human naïve and central memory CD4+ and CD8+ T cells via the mitochondrial pathway by regulating intracellular GSH and the expression of Bax and VDAC.Genes and Immunity 11/2007; 8(7):560-9. · 3.87 Impact Factor -
Article: Role of NF-kappaB signaling pathway in increased tumor necrosis factor-alpha-induced apoptosis of lymphocytes in aged humans.
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ABSTRACT: In human aging, lymphocytes display increased sensitivity to tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis. TNF-alpha induces both survival and apoptotic signals. The survival signal is mediated by the activation of NF-kappaB. Although a role of certain proapoptotic molecules in aging has been reported, a role of altered NF-kappaB signaling pathway has not been explored in detail. In this study, we have compared TNF-alpha-induced activation of NF-kappaB, phosphorylation of IkappaBalpha, and the expression of IKKbeta between lymphocytes from young and aged humans. Furthermore, we have explored a role of IKKbeta in increased susceptibility of lymphocytes from aged humans to TNF-alpha-induced apoptosis. Lymphocytes from aged humans displayed decreased activation of NF-kappaB, reduced phosphorylation of IkappaBalpha, and decreased expression of IKKbeta. In addition, overexpression of IKKbeta in lymphocytes from aged humans normalized TNF-alpha-induced apoptosis to the level of young subjects. These data suggest a deficiency of NF-kappaB signaling pathway and a role of IKKbeta, at least in part, for increased sensitivity of lymphocytes from aged humans to TNF-alpha-induced apoptosis.Cell Death and Differentiation 03/2005; 12(2):177-83. · 8.85 Impact Factor -
Article: Biochemical and molecular basis of thimerosal-induced apoptosis in T cells: a major role of mitochondrial pathway.
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ABSTRACT: The major source of thimerosal (ethyl mercury thiosalicylate) exposure is childhood vaccines. It is believed that the children are exposed to significant accumulative dosage of thimerosal during the first 2 years of life via immunization. Because of health-related concerns for exposure to mercury, we examined the effects of thimerosal on the biochemical and molecular steps of mitochondrial pathway of apoptosis in Jurkat T cells. Thimerosal and not thiosalcylic acid (non-mercury component of thimerosal), in a concentration-dependent manner, induced apoptosis in T cells as determined by TUNEL and propidium iodide assays, suggesting a role of mercury in T cell apoptosis. Apoptosis was associated with depolarization of mitochondrial membrane, release of cytochrome c and apoptosis inducing factor (AIF) from the mitochondria, and activation of caspase-9 and caspase-3, but not of caspase-8. In addition, thimerosal in a concentration-dependent manner inhibited the expression of XIAP, cIAP-1 but did not influence cIAP-2 expression. Furthermore, thimerosal enhanced intracellular reactive oxygen species and reduced intracellular glutathione (GSH). Finally, exogenous glutathione protected T cells from thimerosal-induced apoptosis by upregulation of XIAP and cIAP1 and by inhibiting activation of both caspase-9 and caspase-3. These data suggest that thimerosal induces apoptosis in T cells via mitochondrial pathway by inducing oxidative stress and depletion of GSH.Genes and Immunity 09/2002; 3(5):270-8. · 3.87 Impact Factor -
Article: TNF-alpha-induced apoptosis in neonatal lymphocytes: TNFRp55 expression and downstream pathways of apoptosis.
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ABSTRACT: Previously we have shown decreased Fas-mediated apoptosis in cord blood lymphocyte subsets. In this study, we compared tumor necrosis factor (TNF)-alpha-induced apoptosis in T lymphocytes and their subsets between cord blood and peripheral blood from healthy young controls. The expression of TNF receptor I (TNFR-I) was assessed by flow cytometry and quantitative RT-PCR. The expression of adapter molecules TNF receptor-associated death domain (TRADD), Fas-associated death domain (FADD) and TNF-associated factor-2 (TRAF-2) and caspase 3 was analyzed by Western blotting. The activity of caspase 3 and caspase 8 was measured by colorimetric assay. The susceptibility of CD4+ and CD8+ T cells to TNF-alpha-induced apoptosis was measured by terminal deoxytidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Both CD4+ and CD8+ T cell subsets from cord blood demonstrated decreased susceptibility to TNF-alpha-induced apoptosis that was associated with decreased activation of both caspase 8 and caspase 3 as compared to T cell subsets in peripheral blood. Furthermore, expression of TNFR-I, TRADD and caspase 3 was decreased in cord blood lymphocytes as compared to peripheral blood lymphocytes. The significance of these observations is discussed.Genes and Immunity 02/2000; 1(4):271-9. · 3.87 Impact Factor -
Article: Cartilage-hair hypoplasia syndrome: increased apoptosis of T lymphocytes is associated with altered expression of Fas (CD95), FasL (CD95L), IAP, Bax, and Bcl2.
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ABSTRACT: Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive short-limbed dwarfism associated with thin and sparse hair and cell mediated or combined immunodeficiency. However, the basis of immune deficiency in CHH is unclear. In this study, we investigated a role of apoptosis in immunodeficiency in a patient with CHH. An increased apoptosis of both CD4+ and CD8+ T cells, as determined by TUNEL assay, was observed in CHH compared to an age-matched healthy dwarf control. Increased apoptosis in CHH was associated with increased expression of Fas (CD95), CD95L, and Bax and decreased expression of Bcl-2 and inhibitor of apoptosis protein (IAP) compared to the control. These data suggest that lymphopenia and immunodeficiency in CHH may be, at least in part, due to increased apoptosis of T cells, possibly through the Fas/ FasL signaling pathway.Journal of Clinical Immunology 12/1999; 19(6):428-34. · 3.08 Impact Factor
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Institutions
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1999–2002
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University of California, Irvine
- Department of Medicine
Irvine, CA, USA
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