| 1. |
- Graham, J, et al.
(författare)
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Genetic effects on age-dependent onset and islet cell autoantibody markers in type 1 diabetes
- 2002
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 51:5, s. 1346-1355
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Tidskriftsartikel (refereegranskat)abstract
- Age-dependent associations between type 1 diabetes risk genes HLA, INS VNTR, and CTLA-4 and autoantibodies to GAD65 (GADAs), ICA512/IA-2, insulin, and islet cells were determined by logistic regression analysis in 971 incident patients with type 1 diabetes and 702 control subjects aged 0–34 years. GADAs were associated with HLA-DQ2 in young but not in older patients (P = 0.009). Autoantibodies to insulin were negatively associated with age (P < 0.0001) but positively associated with DQ8 (P = 0.03) and with INS VNTR (P = 0.04), supporting possible immune tolerance induction. ICA512/IA-2 were negatively associated with age (P < 0.0001) and with DQ2 (P < 0.0001) but positively associated with DQ8 (P = 0.04). Males were more likely than females to be negative for GADA (P < 0.0001), autoantibodies to islet cells (P = 0.04), and all four autoantibody markers (P = 0.004). The CTLA-4 3′ end microsatellite marker was not associated with any of the autoantibodies. We conclude that age and genetic factors such as HLA-DQ and INS VNTR need to be combined with islet autoantibody markers when evaluating the risk for type 1 diabetes development.
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| 2. |
- Padoa, CJ, et al.
(författare)
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Recombinant Fabs of human monoclonal antibodies specific to the middle epitope of GAD65 inhibit type 1 diabetes-specific GAD65Abs
- 2003
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 52:11, s. 2689-2695
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Tidskriftsartikel (refereegranskat)abstract
- Autoantibodies to the 65-kDa isoform of GAD (GAD65Abs) are associated with type 1 diabetes development, but the conformational nature of the GAD65Ab epitopes complicates the evaluation of disease risk. Six GAD65-specific recombinant Fabs (rFabs) were cloned from monoclonal antibodies b96.11, DP-C, DP-A, DPD, 144, and 221–442. The binding of GAD65Abs in 61 type 1 diabetic patients to GAD65 was analyzed by competitive radioimmunoassays with the six rFabs to ascertain disease-specific GAD65Ab binding specificities. The median binding was reduced significantly by rFab b96.11 (72%) (P < 0.0001), DP-A (84%) (P < 0.0001), DP-C (84%) (P < 0.0001), 221–442 (79%) (P < 0.0001), and DP-D (80%) (P < 0.0001). The competition pattern in type 1 diabetic patients differed from that in GAD65Ab-positive late autoimmune diabetes in adults (LADA) patients (n = 44), first-degree relatives (n = 38), and healthy individuals (n = 14). Whereas 87 and 72% of the type 1 diabetic sera were competed by rFab b96.11 and DP-C, respectively, only 34 and 26% of LADA patients, 18 and 25% of first-degree relatives, and 7 and 28% of healthy individuals showed competition (P < 0.0001). These findings support the view that type 1 diabetes is associated with disease- and epitope-specific GAD65Abs and supports the notion that the middle epitope is disease associated. These GAD65-specific rFabs should prove useful in predicting type 1 diabetes and in the study of conformational GAD65Ab epitopes.
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| 3. |
- Törn, C., et al.
(författare)
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Prognostic factors for the course of beta cell function in autoimmune diabetes
- 2000
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 85:12, s. 4619-4623
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a 2-yr follow-up of 281 patients, aged 15-34 yr, diagnosed with diabetes between 1992 and 1993. At diagnosis, 224 (80%) patients were positive for at least one of the following autoantibodies: islet cell antibodies (ICAs), glutamic acid decarboxylase antibodies (GADAs), or tyrosine phosphatase antibodies (IA-2As), the remaining 57 (20%) patients were negative for all three autoantibodies. At diagnosis, C-peptide levels were lower (0.27, 0.16-0.40 nmol/L) in autoantibody-positive patients compared with autoantibody-negative patients (0.51, 0.28-0.78 nmol/L, P < 0.001). After 2 yr, C-peptide levels had decreased significantly in patients with autoimmune diabetes (0.20, 0.10-0.37 nmol/L, P = 0.0018), but not in autoantibody-negative patients. In patients with autoimmune diabetes, a low initial level of C-peptide (odds ratio, 2.6, 95% confidence interval, 1.7-4.0) and a high level of GADAs (odds ratio, 2.5, 95% confidence interval, 1.1-5.7) were risk factors for a C-peptide level below the reference level of 0.25 nmol/L 2 yr after diagnosis. Body mass index had a significant effect in the multivariate analysis only when initial C-peptide was not considered. Factors such as age, gender, levels of ICA or IA-2A or insulin autoantibodies (analyzed in a subset of 180 patients) had no effect on the decrease in ▀-cell function. It is concluded that the absence of pancreatic islet autoantibodies at diagnosis were highly predictive for a maintained ▀-cell function during the 2 yr after diagnosis, whereas high levels of GADA indicated a course of decreased ▀-cell function with low levels of C-peptide. In autoimmune diabetes, an initial low level of C-peptide was a strong risk factor for a decrease in ▀-cell function and conversely high C-peptide levels were protective. Other factors such as age, gender, body mass index, levels of ICA, IA-2A or IAA had no prognostic importance.
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