Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0021051 (immunodeficiency)
71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunodysregulation, polyendocrinopathy, enteropathy, X linked (IPEX, OMIM 304790) is a rare, recessive disorder resulting in aggressive autoimmunity and early death. Mutations in FOXP3 have been identified in 13 of 14 patients tested. Research in the mouse model, scurfy, suggests that autoimmunity may stem from a lack of working regulatory T cells. We review published reports regarding the genetics, clinical features, immunology, pathology, and treatment of IPEX. We also report three new patients who were treated with long term immunosuppression, followed by bone marrow transplantation in two. IPEX can be differentiated from other genetic immune disorders by its genetics, clinical presentation, characteristic pattern of pathology, and, except for high IgE, absence of substantial laboratory evidence of immunodeficiency. While chronic treatment with immunosuppressive drugs may provide temporary benefit for some patients, it does not cause complete remission. Remission has been observed with bone marrow transplantation despite incomplete engraftment, but the long term outcome is uncertain.
...
PMID:Clinical and molecular features of the immunodysregulation, polyendocrinopathy, enteropathy, X linked (IPEX) syndrome. 1216 90

In the fifty years since Ogden Bruton discovered agammaglobulinemia, more than 100 additional immunodeficiency syndromes have been described. These disorders may involve one or more components of the immune system, including T, B, and NK lymphocytes; phagocytic cells; and complement proteins. Most are recessive traits, some of which are caused by mutations in genes on the X chromosome, others in genes on autosomal chromosomes. Until the past decade, there was little insight into the fundamental problems underlying a majority of these conditions. Many of the primary immunodeficiency diseases have now been mapped to specific chromosomal locations, and the fundamental biologic errors have been identified in more than 3 dozen. Within the past decade the molecular bases of 7 X-linked immunodeficiency disorders have been reported: X-linked immunodeficiency with Hyper IgM, X-linked lymphoproliferative disease, X-linked agammaglobulinemia, X-linked severe combined immunodeficiency, the Wiskott-Aldrich syndrome, nuclear factor kappaB essential modulator (NEMO or IKKg), and the immune dysregulation polyendocrinopathy (IPEX) syndrome. The abnormal genes in X-linked chronic granulomatous disease (CGD) and properdin deficiency had been identified several years earlier. In addition, there are now many autosomal recessive immunodeficiencies for which the molecular bases have been discovered. These new advances will be reviewed, with particular emphasis on the pulmonary complications of some of these diseases. In some cases there are unique features of lung abnormalities in specific defects. Infections obviously account for most of these complications, but the host reaction to infection often leads to characteristic findings that can be helpful diagnostically. Finally, advances in treatment of the underlying diseases as well as their infectious complications will be covered.
...
PMID:Pulmonary complications of primary immunodeficiencies. 1498 Feb 76

The study of a rare human X-linked disease resulting in a characteristic clinical phenotype of multiple autoimmune disorders and the in-depth exploration of a spontaneous mouse model, scurfy (sf), have contributed to a better understanding of the regulation of immunologic responses, particularly to self. Forkhead box P3 (FOXP3), the gene responsible for IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked) and sf is located on the X chromosome and is of crucial importance for the generation of CD4+ CD25+ regulatory T cells. Loss of FOXP3 function and the resultant lack of regulatory T cells result in lethal auto-aggressive lymphoproliferation, whereas overexpression of this modulator results in severe immunodeficiency. The in-depth analysis of FOXP3 regulation and elucidation of the precise mechanisms by which FOXP3 exerts its regulatory effect will provide important insights into the understanding of autoimmunity and should predictably result in new therapeutic possibilities.
...
PMID:FOXP3 acts as a rheostat of the immune response. 1566 Oct 28

In the most simplistic terms, immune tolerance can be envisioned as a balance with autoreactive cells that arise naturally in all individuals on one side and regulatory mechanisms designed to counter those autoreactive processes on the other. A tilt of the balance toward the autoreactive side, either by increasing the number or function of autoreactive cells or by diminishing regulatory mechanisms, is manifested as autoimmunity. In contrast, tilting of the balance toward increased regulation could conceivably cause immunodeficiency. Regulatory T cells (T(REG)), and particularly the naturally arising CD4(+)CD25(+) subset of T(REG) cells, provide a substantial component of the autoimmune counterbalance. The identification of forkhead box P3 (FOXP3) as a critical determinant of CD4(+)CD25(+) T(REG) development and function has provided new opportunities and generated expanded interest in studying the delicate balance between autoimmunity and regulatory mechanisms in human autoimmune diseases. Identification of both human and mouse syndromes in which FOXP3 is mutated, and consequently CD4(+)CD25(+) T(REG) cells are absent, has led to a rapid accumulation of knowledge regarding T(REG) development and function over the past 5 years. The recent development of antibody reagents to specifically identify CD4(+)CD25(+) T(REG) cells by their FOXP3 expression has provided new tools to identify these elusive cells and investigate their role in human disease. This review will focus on the current state of knowledge regarding the role of T(REG) in human autoimmune diseases and on specific human immunodeficiencies that provide interesting models of autoimmunity.
...
PMID:Regulatory T cells in human autoimmune diseases. 1690 72

Wiskott-Aldrich syndrome protein (WASp) is essential for optimal T cell activation. Patients with WAS exhibit both immunodeficiency and a marked susceptibility to systemic autoimmunity. We investigated whether alterations in Treg function might explain these paradoxical observations. While WASp-deficient (WASp(-/-)) mice exhibited normal thymic Treg generation, the competitive fitness of peripheral Tregs was severely compromised. The total percentage of forkhead box P3-positive (Foxp3(+)) Tregs among CD4(+) T cells was reduced, and WASp(-/-) Tregs were rapidly outcompeted by WASp(+) Tregs in vivo. These findings correlated with reduced expression of markers associated with self-antigen-driven peripheral Treg activation and homing to inflamed tissue. Consistent with these findings, WASp(-/-) Tregs showed a reduced ability to control aberrant T cell activation and autoimmune pathology in Foxp3(-/-)Scurfy (sf) mice. Finally, WASp(+) Tregs exhibited a marked selective advantage in vivo in a WAS patient with a spontaneous revertant mutation, indicating that altered Treg fitness likely explains the autoimmune features in human WAS.
...
PMID:Wiskott-Aldrich syndrome protein is required for regulatory T cell homeostasis. 1721 89

FoxP3 determines the development of CD4+CD25+ regulatory T (Treg) cells and represses interleukin-2 (IL-2) expression in Treg cells. However, human immunodeficiency virus type 1 (HIV-1) infects and replicates efficiently in FoxP3+ Treg cells. We report that, while inhibiting IL-2 gene expression, FoxP3 enhances gene expression from HIV-1 long terminal repeat (LTR). This FoxP3 activity requires both the N- and C-terminal domains and is inactivated by human IPEX (immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome) mutations. FoxP3 enhances HIV-1 LTR via its specific NFkappaB binding sequences in an NFkappaB-dependent fashion in T cells but not in HEK293 cells. FoxP3 decreases level of histone acetylation at the interleukin-2 locus but not at the HIV-1 LTR. Although NFkappaB nuclear translocation is not altered, FoxP3 enhances NFkappaB-p65 binding to HIV-1 LTR. These data suggest that FoxP3 modulates gene expression in a promoter sequence-dependent fashion by modulating chromatin structure and NFkappaB activity. HIV-1 LTR has evolved to both highjack the T-cell activation pathway for expression and to resist FoxP3-mediated suppression of T-cell activation.
...
PMID:FoxP3 enhances HIV-1 gene expression by modulating NFkappaB occupancy at the long terminal repeat in human T cells. 1741 86

Infection with human immunodeficiency virus (HIV) causes a dysregulation of the immune system. This is caused by HIV-specific as well as non-specific mechanisms and has not been explained fully. In particular, knowledge is lacking about the potential role of host-mediated immunosuppressive mechanisms. During recent years it has become evident that a subpopulation of T cells [T regulatory (T(regs))] play a major role in sustaining tolerance to self-antigens. To investigate the influence of initiation of highly active anti-retroviral therapy (HAART) on the T(reg) level in HIV-infected patients we have conducted a prospective study enrolling treatment-naive HIV-infected patients just prior to starting treatment with HAART, measuring levels of T(regs) by flow cytometry and mRNA expression of forkhead box P3 (FoxP3) at weeks 0, 4, 12 and 24 of treatment. In this prospective study neither the percentage of CD4(+)CD25(high+) nor the expression of FoxP3 changed significantly during 24 weeks of HAART. Furthermore, HIV patients have higher T(regs) measured as percentages of CD4(+)CD25(high+) cells paralleled by higher levels of FoxP3 compared with healthy controls. The elevated level of T(regs) was found to be independent of both immunological and virological status, indicating that initiation of HAART has minor effects on the T(reg) level in HIV-infected patients.
...
PMID:Regulatory T cells in human immunodeficiency virus-infected patients are elevated and independent of immunological and virological status, as well as initiation of highly active anti-retroviral therapy. 1882 42

Autoimmune manifestations have long been perceived as paradoxical in patients with primary immune deficiencies (PID). However, a defect in the mechanisms of control of self-reactive B and T cells may favour these manifestations. Three PID are defined by the occurrence of autoimmune manifestations: APECED (Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy), autoimmune lymphoproliferative syndrome (ALPS) and IPEX syndrome (immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome). In these conditions, organ specific autoimmune diseases such as type 1 diabetes mellitus or Hashimoto's thyroiditis are prominently encountered. Several other PID such as common variable immunodeficiency (CVID), Good syndrome and hyper-IgM syndrome are associated with a wide variety of autoimmune manifestations, mainly autoimmune cytopenias. Thus, autoimmune manifestations have been reported in 22% of patients with CVID, increasing to 50% in the subgroup of patients with systemic granulomatosis. Complement deficiencies involving components of the classical pathway are associated with systemic lupus erythematosus (SLE). Homozygous C2 deficiency, which is the most frequent hereditary deficiency in complement classical pathway components, is associated with SLE in 10% of the cases. Complete C1q and C4 deficiencies are less frequent but associated with a higher prevalence of SLE.
...
PMID:Autoimmune manifestations in primary immune deficiencies. 1902 7

CD4(+) regulatory T (T(reg)) cells have been involved in impaired immunity and persistence of viral infections. Herein, we report the level, phenotype and activation status of T(reg) cells in patients chronically infected with human immunodeficiency virus (HIV) and/or hepatitis C virus (HCV). Expression of CD25, CD45RA, CD27, CD127 and CD38 was assessed on these cells using polychromatic flow cytometry in 20 healthy controls, 20 HIV-monoinfected, 20 HCV-monoinfected and 31 HIV/HCV-co-infected patients. T(reg) cells were defined as CD4(+)forkhead box P3 (FoxP3)(+). The percentage of T(reg) cells was increased significantly in HIV patients compared with controls. Moreover, there was a significant inverse correlation between CD4 counts and T(reg) cell levels. Fewer than 50% of T(reg) cells expressed CD25, with differences in terms of CD127 expression between CD25(+) and CD25((-)) T(reg) cells. CD4(+)Foxp3(+) T(reg) cells displayed predominantly a central memory phenotype (CD45RA(-)CD27(+)), without differences between patients and healthy controls. Activated T(reg) cells were increased in HIV patients, particularly considering the central memory subset. In summary, HIV infection, but not HCV, induces an up-regulation of highly activated T(reg) cells, which increases in parallel with CD4 depletion. Hypothetically, this might contribute to the accelerated course of HCV-related liver disease in HIV-immunosuppressed patients.
...
PMID:Level, phenotype and activation status of CD4+FoxP3+ regulatory T cells in patients chronically infected with human immunodeficiency virus and/or hepatitis C virus. 1907 27

After activation by unique cytokines, CD4(+) naive T cells differentiate into lineages of helper/effector (T(H)) and regulatory T (Treg) cells that are characterized by distinct developmental pathways and unique biologic functions. The trusted binary system of T(H)1 and T(H)2 has been expanded to include the IL-17-producing T(H)17 cell lineage, which plays a role in immune responses to infectious agents and maintenance of autoimmune diseases. Acting as counterbalance, Treg cells maintain peripheral tolerance and protect the host from autoaggressive lymphocytes. T(H)1 cells produce IFN-gamma and are involved in cell-mediated immunity, T(H)2 cells produce IL-4 and contribute to humoral immunity, T(H)17 cells generate IL-17 and play an important role in immune responses to fungi and extracellular pathogens, and forkhead box protein 3-positive (FOXP3(+)) Treg cells secrete TGF-beta and IL-10 and downregulate effector T cells. Autosomal dominant hyper-IgE syndrome, a rare primary immunodeficiency disorder, is caused by hypomorphic heterozygous mutations of signal transducer and activator of transcription 3 (STAT3), preventing T(H)17 lineage differentiation and increasing susceptibility to Staphylococcus and Candida species infections. Mutations in the FOXP3 gene interfere with Treg cell development and cause immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome. Other single-gene defects resulting in reduced Treg cell function include CD25, signal transducer and activator of transcription 5b, autoimmune regulator, and Wiskott-Aldrich syndrome protein. These observations emphasize the importance of functionally distinct T-cell lineages in maintaining a balanced innate and cognate immune system.
...
PMID:TH17 cells and regulatory T cells in primary immunodeficiency diseases. 1941 Jun 87


1 2 3 Next >>

---