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 distribution of HLA class II alleles associated with insulin-dependent diabetes mellitus (Type 1) in the Algerian population is poorly known. We have typed 36 Algerian Type 1 diabetic probands and their families using DQA1 and DQB1 oligonucleotide probes. Fifty-nine parental haplotypes non transmitted to diabetic offspring served as controls. The frequencies of DQA1 and DQB1 alleles and haplotypes and their associations with Type 1 diabetes were, except minor differences, similar to those reported in French. Susceptibility DQA1 (Arg52+) and DQB1 (Asp57-) alleles were significantly increased among patients versus controls (90% vs 53%, RR = 8.4, p < 10(-6), and 94% vs 64%, RR = 9.4, p < 10(-5), respectively). 85% of Type 1 diabetics versus 34% of control haplotypes were either DR3DQw2 or DR4DQw8 susceptibility haplotypes (DQA1 Arg52+, DQB1 Asp57-) (RR = 10.8, p < 10(-7). 75% of the probands vs 14% of the controls (RR = 18, p < 10(-5)) and 73% of affected siblings versus 24% of unaffected siblings (RR = 8.4, p < 0.02) possessed a genotype composed of these two susceptibility haplotypes in the homozygous or heterozygous state. 42% of the probands were DR3DQw2/DR4DQw8, corresponding to Hardy-Weinberg expectations. The lack of excess of heterozygotes could be due to the consanguine families in this sample, as among the patients with consanguine parents the frequency of DR3, 4 heterozygotes was lower (27% vs 48% in non-consanguine patients, NS) and that of DR3 homozygotes increased (45% vs 12%, respectively, p < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:HLA DQA1 and DQB1 study in Algerian type 1 diabetes families. 129 2

International comparative molecular studies of insulin-dependent diabetes mellitus can be viewed from an immunogenetical and an epidemiological perspective. Each approach independently contributes to our knowledge concerning the etiology and prevention of the disease. However, the combination of these perspectives, representing an interface between molecular biology and epidemiology, will achieve more in terms of scientific advancement and public health than either perspective alone. An excellent example of the development of molecular epidemiology has been the evolution of international comparative research through the WHO Multinational Project for Childhood Diabetes. Case-control molecular studies are currently being conducted to test the hypothesis that population variation in the frequency of HLA class II susceptibility alleles is the primary determinant of the global patterns of insulin-dependent diabetes mellitus incidence. Preliminary data suggest that this hypothesis is correct. Future international molecular epidemiological studies, encompassing host-environment interactions, will lead to a better understanding of the relationships among specific risk factors within populations and across the world. Molecular epidemiology represents a new paradigm for studying the etiology and epidemiology of infectious and non-communicable diseases, and no doubt represents a major challenge for the 1990s.
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PMID:Genetic epidemiology of insulin-dependent diabetes mellitus: international comparisons using molecular genetics. 141 25

The association of insulin-dependent diabetes mellitus (IDDM) with certain HLA alleles is well documented in pediatric patients. Whether a similar association is found in adult-on-set IDDM is not clear, although the disease occurs after the age of 20 in 50% of cases. HLA class II DRB1, DQA1, and DQB1 alleles were studied in 402 type I diabetics and 405 healthy controls (all Caucasian) using oligonucleotide typing after gene amplification. Alleles DRB1*03, DRB1*04, DQB1*0201, DQB1*0302, DQA1*0301, and DQA1*0501 were indeed enriched in diabetics and the highest relative risk was observed in patients carrying both the DRB1*03-DQB1*0201 and the DRB1*0402 or DRB1*0405-DQB1*0302 haplotypes. However none of these alleles, or specific residues, could alone account for the susceptibility to IDDM. Furthermore, there were major differences in HLA class II gene profiles according to the age of onset. Patients with onset after 15 yr (n = 290) showed a significantly higher percentage of non-DR3/non-DR4 genotypes than those with childhood onset (n = 112) and a lower percentage of DR3/4 genotypes. These non-DR3/non-DR4 patients, although presenting clinically as IDDM type 1 patients, showed a lower frequency of islet cell antibodies at diagnosis and a significantly milder initial insulin deficiency. These subjects probably represent a particular subset of IDDM patients in whom frequency increases with age. The data confirm the genetic heterogeneity of IDDM and call for caution in extrapolating to adult patients the genetic concepts derived from childhood IDDM.
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PMID:Age-dependent HLA genetic heterogeneity of type 1 insulin-dependent diabetes mellitus. 146 84

Autoimmune diseases result from the activation of self-reactive T cells induced by autoantigens or by foreign antigens cross-reactive with an autoantigen. A striking characteristic of autoimmune diseases is the increased frequency of certain HLA alleles in affected individuals. Moreover, as demonstrated for example in rheumatoid arthritis and insulin-dependent diabetes mellitus, class II alleles positively associated with autoimmune diseases share amino acid residues in the hypervariable HLA regions involved in peptide binding. Therefore, it is likely that disease-associated HLA class II molecules have the capacity to bind the autoantigen and present it to T cells, thereby inducing and maintaining, under appropriate conditions, the autoimmune disease. The data reviewed here demonstrate MHC-selective inhibition of antigen-induced T cell responses in vivo by parenterally administered soluble, MHC-binding peptide competitors, under conditions in which the competitor is not immunogenic. This suggests the feasibility of a therapeutic approach based on blockade of MHC class II molecules in the treatment of HLA-linked autoimmune diseases.
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PMID:Inhibition of T cell activation by MHC blockade: a possible strategy for immunointervention in autoimmune diseases. 150 37

HLA class II antigens are transmembrane glycosylated heterodimers composed of an alpha and a beta chain. Several of these chains are highly polymorphic. The structural bases of the polymorphism are nucleotide acid substitutions which are situated in the first domain (exon II) of alpha and beta genes. Specific sequences of these domains can be obtained by amplification of genomic DNA using the polymerase chain reaction. Polymorphic sites are recognized by restriction endonuclease treatment and separation of the DNA fragments by polyacrylamide gel electrophoresis. The resulting fragments of different lengths are used to identify different alleles. We used the above technique for typing the HLA-DQA1 alleles in 41 Tunisian diabetic patients. The frequency of DQA1*0301 was greatly increased compared with the control group. This was in agreement with previously published data in Caucasian and Japanese insulin-dependent diabetes mellitus (IDDM) patients, while the significant increase in the frequency of the DQA1*0501 allele was comparable with that of Caucasian IDDM patients but contrasted with a decrease in this allele in Japanese IDDM patients. Our results provide confirmation of the contribution of the DQA1*0301 allele to disease susceptibility in a Tunisian population.
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PMID:Association of type 1 diabetes mellitus with the HLA-DQA1*0301 allele in a Tunisian population. 168 Feb 41

Eighty unrelated diabetic children, seventy healthy controls and hundred and ten affected and unaffected first-degree relatives of twenty multiplex families were investigated by restriction fragment length polymorphism analysis of HLA class II genes using five probe/enzyme systems: DRB and DQB/Taq I, DRB and DQB/EcoRI and DQB/BamHI according to standard procedures described in the 10th Histocompatibility Workshop protocol. Comparison between the unrelated diabetic patients and the controls confirmed the positive association of type 1 diabetes with DR3(w17)DQw2 Dw24 or Dw25 and DR4DQw8 and the negative association with DR2(w15)DQw6, DR4DQw7 and DR7DQw2 haplotypes. In multiplex families, similar allele associations were found and the distinction between haplotypes present in diabetic patients and those that segregated to healthy family members allowed to observe striking differences between the "affected" and "unaffected" haplotypes, particularly for the subtypes of DR3(w17) DQw2, DR4DQw3 and DR2DQw1 haplotypes. Heterozygous siblings who carried both DR3DQw2 and DR4DQw8 subtypes disclosed a highly increased risk and more than 80% of DR3/DR4 affected siblings received a paternal DR4DQw8 together with a maternal DR3DQw2. These observations indicate that several genetic aspects influence susceptibility to type 1 diabetes: 1) some particular HLA class II subsets; 2) the parental origin of the predisposing genes; 3) the synergistic effect of both haplotypes, in particular DR3DQw2 and DR4DQw8. These results may help to better specify susceptibility markers for risk prediction in siblings.
Diabetes Res 1991 Oct
PMID:DNA polymorphism analysis of HLA class II genes in unrelated children and in first-degree relatives with type I diabetes. 168 61

Interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha (TNF-alpha) may be pathogenetically important in insulin-dependent diabetes mellitus (IDDM), which is associated with genes of the HLA region. Since a regulatory role of HLA region genes on monokine production may exist, we looked for an association between the monokine and prostaglandin E2 (PGE2) responses of monocytes (Mo) from 20 healthy males (18-50 years) with HLA-DR types relevant for IDDM susceptibility and resistance (DR1,2, DR1,3, DR1,4, DR3,4). Monokine assays were established and evaluated and the secretions of IL-1 beta, TNF-alpha, and PGE2 measured in Mo cultures (2h, 6h, 20h) prepared by endotoxin-free techniques and stimulated by low-dose E. coli lipopolysaccharides (LPS). There were no significant associations between Mo responses and HLA-DR phenotype. Likewise, Mo from DR2 (n = 5) and DR4 (n = 5) homozygous healthy males demonstrated no significant differences in monokine and PGE2 responses of Mo. In the HLA class III region a diallelic TNF-beta gene NcoI polymorphism consisting of alleles of 5.5 kb and 10.5 kb was recently described and associated with susceptibility to autoimmune diseases including IDDM. We report that IL-1 beta and TNF-alpha responses of Mo from TNF-beta 10.5 kb homozygous healthy individuals were significantly higher than for TNF-beta 5.5/10.5 kb heterozygotes. IL-1 beta and TNF-alpha responses of Mo from males (18-35 years) with newly diagnosed (n = 10) and long-standing IDDM (n = 10) and from age- and HLA-DR-matched healthy males (n = 10) were studied. LPS, gamma interferon (IFN), and TNF-alpha-stimulated Mo cultures were investigated. No significant differences were found between Mo responses of IDDM patients and controls. IFN (1000 U/ml) in the presence of LPS significantly potentiated LPS-stimulated Mo TNF-alpha secretion and reduced the levels of IL-1 beta immunoreactivity in Mo lysates. IFN and TNF-alpha did not have any effects on LPS-stimulated Mo secretion of IL-1 beta immunoreactivity. We conclude that Mo IL-1 beta and TNF-alpha production is normal in patients with recent-onset and long-standing IDDM. The interindividual differences in monokine responses may be accounted for by the diallelic human TNF-beta gene polymorphism rather than by HLA class II genes. This observation may be important for understanding the association of certain HLA haplotypes with autoimmune phenomena and disease.
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PMID:Monocyte function in IDDM patients and healthy individuals. 169 9

Graves disease is a common form of human autoimmune thyroiditis. It shares many pathological features and HLA associations with other, less easily studied, organ-specific autoimmune conditions such as insulin-dependent diabetes mellitus, and hence it is also a useful model for understanding these other diseases. We have previously shown that thyroid-infiltrating T cells in Graves disease that have been recently activated in vivo specifically recognize autologous thyroid epithelial cells. However, the autoantigens involved were not defined. In this study, we have made use of antigen-independent T-cell cloning techniques to show that at least three different thyroid antigens, three different epitopes on a single antigen, and two HLA class II elements are involved in this recognition process in a single individual. This demonstrates that T cells that are present and activated at the site of a human autoimmune disease may show considerable heterogeneity in their recognition of autoantigen on the target tissue. This contrasts with the limited heterogeneity recently reported in some animal models and has potentially important implications for both our understanding of the autoimmune process in humans and the design of immunotherapies to reverse it.
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PMID:Autoantigen recognition by thyroid-infiltrating T cells in Graves disease. 171 2

Immune activation events regulated by the human MHC are triggered by interactions between HLA class II molecules, antigenic peptides, and reactive T cells. In most autoimmune diseases, little is known about the latter two elements of this trimolecular complex, while the HLA class II contribution is being deciphered in increasingly sophisticated detail. In two cases in particular, type I diabetes and rheumatoid arthritis, susceptibility is tied to structural elements within specific HLA class II genes. Site-directed mutagenesis and gene expression studies provide a means to directly test the contribution of specific residues within individual candidate disease susceptibility genes to peptide and T cell interactions.
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PMID:Mutagenesis and expression of putative class II susceptibility genes: a "reverse immunogenetics" approach to analysis of HLA and disease. 171 79

Autoimmune diseases result from the activation of self-reactive T cells induced by autoantigens or by foreign antigens cross-reactive with an autoantigen. A striking characteristic of autoimmune diseases is the increased frequency of certain HLA alleles in affected individuals. Moreover, as demonstrated for example in rheumatoid arthritis and insulin-dependent diabetes mellitus, class II alleles positively associated with autoimmune diseases share amino acid residues in the hypervariable HLA regions involved in peptide binding. Therefore, it is likely that disease-associated HLA class II molecules have the capacity to bind the autoantigen and present it to T cells, thereby inducing and maintaining, under appropriate conditions, the autoimmune disease. The data reviewed here demonstrate MHC-selective inhibition of antigen-induced T cell responses in vivo by parenterally administered soluble, MHC-binding peptide competitors, under conditions in which the competitor is not immunogenic. This suggests the feasibility of a therapeutic approach based on MHC blockade in the treatment of HLA-linked autoimmune diseases.
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PMID:Inhibition of T cell activation by blockade of MHC class II molecules. 193 5


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