Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of non-HLA single nucleotide polymorphisms from a panel of candidate genes in genetic susceptibility to type I diabetes (TID) among Filipinos was examined by PCR/SSOP typing of 90 patients and 94 controls, previously typed for the HLA class I and class II loci. We report the association of CTLA-4 A49G variation (cytotoxic T-lymphocyte associated-4) to TID among Filipinos, consistent with some but not all previous reports in other ethnic groups. The G allele frequency (0.61 versus 0.45, P=0.003) and GG genotype frequency (0.42 versus 0.22, P=0.004) were each increased in patients compared to controls, respectively. Among Filipinos, the CTLA-4 genotypes are associated with disease only in the presence of the predisposing DR3, 4, and 9 haplotypes (P=0.012). Compared to the AA genotype, the increased risk of diabetes predisposition is greatest in genotype GG bearing the DR susceptible alleles (DR3, 4, and 9) (odds ratio=4.6, P=0.001), demonstrating that non- HLA loci, acting in concert with HLA, can play potent roles in modifying susceptibility to TID.
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PMID:Association of CTLA-4 variation with type I diabetes in Filipinos. 1218 34

Dimeric Fc receptor (FcR) nonbinding anti-CD3 antibodies have been developed to minimize toxicities associated with classical anti-CD3 monoclonal antibodies (e.g., OKT3). Studies with murine analogs of non-FcR-binding antibodies have shown reduced mitogenicity compared to OKT3. In a trial of an FcR nonbinding humanized anti-CD3 mAb hOKT3gamma1(Ala-Ala) for treatment of patients with type 1 diabetes, we found significant increases in IL-10 and IL-5 in the serum of 63% and 72% of patients, respectively, and TNF-alpha and IL-6 levels that were lower than those previously reported following OKT3 therapy. The activation signal delivered by hOKT3gamma1(Ala-Ala) was associated with calcium signaling and cytokine production by previously activated human cells in vitro. However, the production of IL-10, compared to IFN-gamma on a molar basis, was greater after culture with hOKT3gamma1(Ala-Ala) than with OKT3. Flow cytometric studies confirmed that OKT3 induced IFN-gamma and IL-10 production, but hOKT3gamma1(Ala-Ala) induced only detectable IL-10 production in CD45RO(+) cells. Moreover, in vivo, we found IL-10(+)CD4(+) T cells after drug treatment. These cells were heterogeneous but generally CD45RO(+), CTLA-4(-), and expressed CCR4. A subgroup of these cells expressed TGF-beta. Thus, the non-FcR binding anti-CD3 mAb, hOKT3gamma1(Ala-Ala) delivers an activation signal to T cells that is quantitatively and qualitatively different from OKT3. It leads to the generation of T cells that might inhibit the autoimmune response and may be involved in the beneficial effect on beta cell destruction in Type 1 diabetes.
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PMID:Activation of human T cells by FcR nonbinding anti-CD3 mAb, hOKT3gamma1(Ala-Ala). 1256 67

Dendritic cells (DCs) not only induce but also modulate T cell activation. 1,25-Dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] induces DCs with a tolerogenic phenotype, characterized by decreased expression of CD40, CD80, and CD86 co-stimulatory molecules, low IL-12, and enhanced IL-10 secretion. We have found that a short treatment with 1,25-(OH)(2)D(3) induces tolerance to fully mismatched mouse islet allografts, and that this tolerance is stable to challenge with donor-type spleen cells and allows acceptance of donor-type vascularized heart grafts. This effect is enhanced by co-administration of mycophenolate mofetil (MMF), a selective inhibitor of T and B cell proliferation, that also has effects similar to 1,25-(OH)(2)D(3) on DCs. Graft acceptance is associated with impaired development of type 1 CD4(+) and CD8(+) cells and an increased percentage of CD4(+)CD25(+) regulatory cells expressing CD152 in the spleen and in the draining lymph node. Transfer of CD4(+)CD25(+) cells from tolerant mice protects 100% of the syngeneic recipients from islet allograft rejection. CD4(+)CD25(+) cells that are able to inhibit the T cell response to a pancreatic autoantigen and to significantly delay disease transfer by pathogenic CD4(+)CD25(-) cells are also induced by treatment of adult nonobese diabetic (NOD) mice with a selected vitamin D receptor (VDR) ligand. This treatment arrests progression of insulitis and Th1 cell infiltration, and inhibits diabetes development at non-hypercalcemic doses. The enhancement of CD4(+)CD25(+) regulatory T cells able to mediate transplantation tolerance and to arrest type 1 diabetes development by a short oral treatment with small organic compounds that induce tolerogenic DCs, like VDR ligands, suggests possible clinical applications of this approach.
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PMID:Tolerogenic dendritic cells induced by vitamin D receptor ligands enhance regulatory T cells inhibiting autoimmune diabetes. 1272 48

We have recently described an impaired proliferative response of CD4(+) T-cells to primary antigens in patients with insulin-dependent diabetes mellitus (IDDM) [Clin. Immunol. 103 (2002) 249]. In order to further investigate possible mechanisms underlying this impairment, several factors known to be involved in the down-regulation of the immune response both at the level of APCs and CD4(+) T-cells were investigated: Monocyte-derived dendritic cells (MDDC) from IDDM patients were shown to express elevated amounts of CD86 (B7.2) (p=0.003) and reduced amounts of the adhesion molecule CD54 (ICAM-1) (p=0.03) on their cell surface compared to age-matched healthy controls and patients with non-insulin-dependent diabetes mellitus (NIDDM) as well as decreased SDS-PAGE stability of HLA-DQ and -DR peptide complexes directly isolated from the IDDM patients' peripheral blood mononuclear cells (PBMCs). Expression of CTLA-4 (CD152), known to be involved in the down-regulation of the immune response, was shown to be increased on CD4(+) T-cells from IDDM patients after exposure to the primary antigen KLH (keyhole limpet hemocyanin) presented by MDDC (p=0.0047). Likewise, purified CD4(+) T-cells from IDDM patients produced elevated levels of the cytokine TGF-beta1 after stimulation with immobilized monoclonal antibodies directed against CD3 and CD28 (p=0.014). When monocytes from IDDM patients were stimulated with lipopolysaccharide (LPS), an increased tendency to produce the inhibitory cytokine interleukin (IL)-10 (p=0.007) and the acute phase cytokine IL-6 (p=0.044) was observed, whereas the concentrations of tumor necrosis factor (TNF)-alpha, IL-1beta, and IL-12 were comparable to controls. Taken together, our data suggest that a deviation in the expression of certain molecules known to be involved in the peripheral control of the immune response is present in IDDM patients and is underlying the observed impairment of the primary immune response.
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PMID:Impaired primary immune response in type-1 diabetes. Functional impairment at the level of APCs and T-cells. 1274 78

Since negative selection in the thymus is incomplete, some self-reactive T cells are able to mature and seed the periphery. To study how these T cells interact following encounter with the self-protein they recognize in the periphery, we have developed an adoptive transfer system in which HEL-specific TCR transgenic CD4 T cells are transferred to mice expressing HEL protein in the pancreas under the control of the rat insulin promoter. Here we show that after adoptive transfer of HEL-specific T cells functional tolerance is maintained despite evidence that the T cells encounter and respond to pancreas-expressed antigen. Even the provision of an additional activation stimulus by peripheral immunization with HEL protein is insufficient to induce the T cells to cause autoimmune tissue injury. However, in the presence of blocking anti-CTLA-4-mAb, immunized adoptive transfer recipients rapidly developed diabetes. These data suggest that the CTLA-4 pathway regulates the pathogenicity of antigen-specific T cells following a peripheral activation stimulus.
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PMID:Functional tolerance is maintained despite proliferation of CD4 T cells after encounter with tissue-derived antigen. 1288 58

Type 1 diabetes (T1D) and the autoimmune thyroid diseases (AITD) are the most common autoimmune endocrine diseases. Both are organ-specific T-cell mediated diseases. Abundant epidemiological data support a strong genetic basis for both T1D and AITD. Furthermore, both diseases commonly occur in the same individuals and in the same families. Indeed, studies suggest that the etiology of T1D and AITD may involve common genetic factors. Two immune regulatory genes, HLA and CTLA-4 contribute to the susceptibility to both diseases. Additionally, two tissue-specific genes, the insulin VNTR in T1D and Thyroglobulin in AITD play a major role in their pathogenesis. Therefore, it is likely that both immune regulatory and target tissue genes contribute to these and other autoimmune diseases.
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PMID:The etiology of autoimmune diabetes and thyroiditis: evidence for common genetic susceptibility. 1455 Aug 80

Interleukin-18 (IL-18) is a potent proinflammatory cytokine which is strongly associated with the development of diabetes in NOD mice. To test the putative involvement of IL-18 gene polymorphism in predisposition to human type 1 diabetes, the SNPs at position -607 (C/A) and -137 (G/C) in the promoter region of IL-18 gene were analyzed by sequence-specific PCR in 116 patients with type 1 diabetes and 114 normal controls. A linkage disequilibrium found only three of the four possible haplotypes defined by these SNPs. The distribution of the IL-18 gene genotypes at position -607 was significantly different between patients with type 1 diabetes and normal controls (P=0.023). Furthermore, there was a significant increase in haplotype 1 (-607C/-137G) in the patients compared with controls (P=0.006). The association study of the susceptible CTLA-4 genotype (GG at nucleotide position 49 in exon 1) or HLA-DR4-DQB1*0401 and type 1 diabetes showed that the predisposing IL-18 gene haplotype modulates the risk on CTLA-4 GG genotype, but not on HLA-DR4-DQB1*0401 haplotype. Among subjects carrying the CTLA-4 GG genotype, the frequency of IL-18 haplotype 1 in patients with type 1 diabetes was significantly higher than that in controls (91% vs. 71%, P=0.012). However, IL-18 haplotype 1 was not frequent in patients who do not exhibit the CTLA-4 high-risk genotype. These results suggest that the IL-18 gene polymorphism is associated with a type 1 diabetes susceptibility, and there might be a gene-gene interaction between IL-18 gene with susceptible CTLA-4 gene.
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PMID:Association between IL-18 gene promoter polymorphisms and CTLA-4 gene 49A/G polymorphism in Japanese patients with type 1 diabetes. 1470 15

The presence of islet cell autoantibodies (ICA), and especially of glutamic acid decarboxylase autoantibodies (GAD65Ab), in patients with non-insulin-dependent diabetes mellitus identifies the so-called latent autoimmune diabetes in the adult (LADA). LADA patients have an increased risk for developing insulin deficiency, and in 60-80% of cases the exogenous insulin therapy must be started within 5-6 years. GAD65Ab identify a subgroup of type 2 diabetic (T2DM) patients with low body mass index (BMI) at the time of diagnosis. The presence of GAD65Ab at high titres and directed against COOH-terminal epitopes of the autoantigen, or the presence of both GAD65Ab and ICA, discriminates patients with clinical characteristics very similar to those of a slowly progressive form of type 1 diabetes (T1DM). On the other hand, the presence of low levels GAD65Ab, in the absence of ICA or other immune markers, such as IA-2 antibodies, characterizes a subgroup of patients with clinical characteristics almost indistinguishable from those of typical T2DM patients. The autoimmune origin of LADA is also demonstrated by the increased frequency of thyroid and adrenal autoantibodies, as compared to GAD65Ab-negative T2DM patients, and by the strong genetic association with HLA-DR3-DQ2, -DR4-DQ8 and the polymorphisms of the MHC class I chain-related A (MICA) and CTLA-4 genes. Metabolic studies have shown the coexistence of insulin resistance and insulin secretion defect supporting the hypothesis that LADA may be the result of the interaction of a genetic background predisposing for islet autoimmunity and a genetic background predisposing for T2DM.
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PMID:[Immunologic and genetic aspects of latent autoimmune diabetes in the adult]. 1475

An individual's predisposition to Type I diabetes (T1D) is largely determined by complex interactions between several genetic loci and other, nonheritable factors. In T1D, the HLA locus has been known for decades to contribute 50% of the inherited risk. Outside the HLA are many proposed candidate loci with smaller effects, but only two confirmed candidate genes, the INS-VNTR and the CTLA-4 genes, which together do not contribute more than 15% of the risk. Because of the high frequency of the disease-associated DNA variants of these genes, understanding the biological mechanisms of such DNA variation in the context of T1D can have tremendous impact on the development of preventive therapeutics. However, establishing a causal relationship between common DNA variations and disease-predisposing functional effects is not trivial and remains difficult, as the effects are expected to be subtle. The variable-number tandem-repeat (VNTR) region upstream of the insulin gene is known to mediate expression in the thymus and pancreas, whereas various polymorphisms in the 5' and 3' regulatory regions of CTLA-4 are thought to alter gene expression and a coding A49G polymorphism exerts effects on post-translational processing. This review details the latest efforts in elucidating the functional mechanisms that explain the genetic association of the INS-VNTR and CTLA-4 genes with T1D.
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PMID:Mechanisms of genetic susceptibility to type I diabetes: beyond HLA. 1497 24

CD4+CD25+ regulatory T cells are essential in the protection from organ-specific autoimmune diseases. In the pancreas, they inhibit actions of autoreactive T cells and thereby prevent diabetes progression. The signals that control the generation, the maintenance, or the expansion of regulatory T cell pool in vivo remain poorly understood. Here we show that a transient pulse of transforming growth factor beta (TGF-beta) in the islets during the priming phase of diabetes is sufficient to inhibit disease onset by promoting the expansion of intraislet CD4+CD25+ T cell pool. Approximately 40-50% of intraislet CD4+ T cells expressed the CD25 marker and exhibited characteristics of regulatory T cells including small size, high level of intracellular CTLA-4, expression of Foxp3, and transfer of protection against diabetes. Results from in vivo incorporation of BrdUrd revealed that the generation of a high frequency of regulatory T cells in the islets is due to in situ expansion upon TGF-beta expression. Thus, these findings demonstrate a previously uncharacterized mechanism by which TGF-beta inhibits autoimmune diseases via regulation of the size of the CD4+CD25+ regulatory T cell pool in vivo.
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PMID:TGF-beta regulates in vivo expansion of Foxp3-expressing CD4+CD25+ regulatory T cells responsible for protection against diabetes. 1507 Jul 59


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