| 1. |
- Vaziri Sani, Fariba, et al.
(författare)
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A novel triple mix radiobinding assay for the three ZnT8 (ZnT8-RWQ) autoantibody variants in children with newly diagnosed diabetes
- 2011
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Ingår i: JIM - Journal of Immunological Methods. - : Elsevier. - 0022-1759 .- 1872-7905. ; 371:1-2, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Autoantibodies against the zinc transporter 8 (ZnT8A) are common in type 1 diabetes (T1D). ZnT8A analyses are complicated by the fact that there are three variants of the autoantigen at amino acid position 325 representing ZnT8-R (Arginine), ZnT8-W (Tryptophan) and ZnT8-Q (Glutamin). The aims of the study were: 1) to develop an autoantigen triple mix Radio-Binding Assay (RBA) for ZnT8A: 2) to identify the individual ZnT8-R,-W,-QA reactivity and 3) to validate the triple mix ZnT8A RBA in children with newly diagnosed T1D. less thanbrgreater than less thanbrgreater thanMethods: Serum samples were obtained from 2664 (56% males, n = 1436) patients in the Swedish nationwide Better Diabetes Diagnosis (BDD) study representing patients with T1D (97%, n = 2582), T2D (1.7%, n = 46), MODY (1.0%, n = 28) and secondary diabetes (0.3%, n = 8). cDNA coding for the C-terminal end of each variant was prepared by site-directed mutagenesis and subcloned into a high efficiency in vitro transcription translation vector. The ZnT8 variants were labeled with 35S-methionine and used in a standard RBA separating free from autoantibody-bound autoantigen with Protein A-Sepharose. less thanbrgreater than less thanbrgreater thanResults: ZnT8-TripleA was detected in 1678 (65%) patients with T1D, 4 (9%) T2D, 3 (11%) MODY and in none (0%) of the patients with secondary diabetes. Among the T1D patients ZnT8-RA was detected in 1351 (52%) patients, ZnT8-WA in 1209(47%) and ZnT8-QA in 790(31%) demonstrating that 1661 (64%) had one or several ZnT8A. The ZnT8-TripleA assay showed a false positive rate of 1.9% (n = 49). Only 1.2% (n = 32) of the T1D patients were false negative for ZnT8-TripleA compared to 0/46(0%) of the T2D patients. The precision (intra assay CV) and reproducibility (inter assay CV) of the ZnT8-TripleA assay did not differ from the RBA of the individual ZnT8 variants. less thanbrgreater than less thanbrgreater thanConclusion: We conclude that the ZnT8-TripleA assay had low false positive and false negative rates. The ZnT8-TripleA assay would therefore be highly suitable not only to analyze patient with newly diagnosed diabetes but also for screening the general population since this assay demonstrated high sensitivity and very high specificity.
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| 2. |
- Andersen, Marie Louise M., et al.
(författare)
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Association between autoantibodies to the Arginine variant of the Zinc transporter 8 (ZnT8) and stimulated C-peptide levels in Danish children and adolescents with newly diagnosed type 1 diabetes
- 2012
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Ingår i: Pediatric Diabetes. - : Hindawi Limited. - 1399-543X .- 1399-5448. ; 13:6, s. 454-462
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Tidskriftsartikel (refereegranskat)abstract
- Background The zinc transporter 8 (ZnT8) was recently identified as a common autoantigen in type 1 diabetes (T1D) and inclusion of ZnT8 autoantibodies (ZnT8Ab) was found to increase the diagnostic specificity of T1D. Objectives The main aims were to determine whether ZnT8Ab vary during follow-up 1 year after diagnosis, and to relate the reactivity of three types of ZnT8Ab to the residual stimulated C-peptide levels during the first year after diagnosis. Subjects A total of 129 newly diagnosed T1D patients <15 years was followed prospectively 1, 3, 6, and 12 months after diagnosis. Methods Hemoglobin A1c, meal-stimulated C-peptide, ZnT8Ab, and other pancreatic autoantibodies were measured at each visit. Patients were genotyped for the rs13266634 variant at the SLC30A8 gene and HLA-DQ alleles. Results The levels of all ZnT8Ab [ZnT8Arg (arginine), ZnT8Trp (tryptophan), ZnT8Gln (glutamine)] tended to decrease during disease progression. A twofold higher level of ZnT8Arg and ZnT8Gln was associated with 4.6%/5.2% (p = 0.02), 5.3%/8.2% (p = 0.02) and 8.9%/9.7% (p = 0.004) higher concentrations of stimulated C-peptide 3, 6, and 12 months after diagnosis. The TT genotype carriers of the SLC30A8 gene had 45.8% (p = 0.01) and 60.1% (p = 0.002) lower stimulated C-peptide 6 and 12 months after diagnosis compared to the CC and the CT genotype carriers in a recessive model. Conclusions The levels of the Arg variant of the ZnT8 autoantibodies are associated with higher levels of stimulated C-peptide after diagnosis of T1D and during follow-up. Carriers of the TT genotype of the SLC30A8 gene predict lower stimulated C-peptide levels 12 months after diagnosis.
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| 3. |
- Wiberg, Anna, 1987-
(författare)
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Immunopathology of the Pancreas in Type 1 Diabetes
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Type 1 diabetes (T1D) results from a loss of functional insulin-producing pancreatic beta cells. The etiology of T1D is poorly understood, but the detection of infiltrating inflammatory cells in the pancreas and circulating autoantibodies has led to the common notion that an autoimmune process plays a central role in the pathogenesis of the disease.The aim of this doctoral thesis was to assess various aspects of the immunopathology of type 1 diabetes. To this purpose, studies have been conducted on pancreatic material from the Network for Pancreatic Organ Donors with Diabetes (nPOD) collection, the Nordic Network for Islet Transplantation, and the Diabetes Virus Detection (DiViD) study.Paper I is a study on pancreatic tissue from organ donors with varying duration of T1D as well as non-diabetic donors and subjects with other types of diabetes, in which persistent expression of glucose transporters was shown on the beta cell membrane despite several years of T1D. Glucose transporter 1 was also confirmed as the predominant glucose transporter on human pancreatic islets. In paper II, we report on signs of inflammation in the exocrine but not in the endocrine pancreas in non-diabetic organ donors with diabetes-related autoantibodies, suggesting that diabetes-associated autoantibodies can occur in response to unspecific pancreatic lesions.Paper III aimed to characterize the T cell-infiltration of pancreatic islets in material from recent-onset T1D patients. Insulitis was shown in all subjects, but with distinct differences in expression analysis of T- and B cell activation to cell-mediated allorejected kidney transplant. Also Paper IV was conducted on material from recent-onset cases and showed increased islet glucagon content, in combination with a reduced number of islets but sustained mean islet size.Together, these results provide expansion of our knowledge of the immunopathology in T1D, and will hopefully assist in bringing us towards a deeper understanding of T1D aetiology and eventually an effective cure.
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| 4. |
- Mendu, Suresh Kumar, et al.
(författare)
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Increased GABA(A) channel subunits expression in CD8(+) but not in CD4(+) T cells in BB rats developing diabetes compared to their congenic littermates
- 2011
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 48:4, s. 399-407
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Tidskriftsartikel (refereegranskat)abstract
- GABA (γ-aminobutyric acid), the main inhibitory neurotransmitter in the central nervous system is also present in the pancreatic islet β cells where it may function as a paracrine molecule and perhaps as an immunomodulator of lymphocytes infiltrating the pancreatic islet. We examined CD4(+) and CD8(+) T cells from diabetes prone (DR(lyp/lyp)) or resistant (DR(+/+)) congenic biobreeding (BB) rats for expression of GABA(A) channels. Our results show that BB rat CD4(+) and CD8(+) T cells express α1, α2, α3, α4, α6, β3, γ1, δ, ρ1 and ρ2 GABA(A) channel subunits. In CD8(+) T cells from DR(lyp/lyp) animals the subunits were significantly upregulated relative to expression levels in the CD8(+) T cells from DR(+/+) rats as well as from CD4(+) T cells from both DR(lyp/lyp) and DR(+/+) rats. Functional channels were formed in the T cells and physiological concentrations of GABA (100 nM) decreased T cell proliferation. Our results are consistent with the hypothesis that GABA in the islets of Langerhans may diminish inflammation by inhibition of activated T lymphocytes.
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| 5. |
- Svensson, Matilda1, et al.
(författare)
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Antibodies to Influenza Virus A/H1N1 Hemagglutinin in Type 1 Diabetes Children Diagnosed Before, During and After the SWEDISH A(H1N1)pdm09 Vaccination Campaign 2009-2010
- 2014
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 79:2, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- We determined A/H1N1-hemagglutinin (HA) antibodies in relation to HLAD-Q genotypes and islet autoantibodies at clinical diagnosis in 1141 incident 0.7 to 18-year-old type 1 diabetes patients diagnosed April 2009-December 2010. Antibodies to S-35-methionine-labelled A/H1N1 hemagglutinin were determined in a radio-binding assay in patients diagnosed before (n = 325), during (n = 355) and after (n = 461) the October 2009-March 2010 Swedish A(H1N1) pdm09 vaccination campaign, along with HLA-DQ genotypes and autoantibodies against GAD, insulin, IA-2 and ZnT8 transporter. Before vaccination, 0.6% patients had A/H1N1-HA antibodies compared with 40% during and 27% after vaccination (P less than 0.0001). In children less than3 years of age, A/H1N1-HA antibodies were found only during vaccination. The frequency of A/H1N1-HA antibodies during vaccination decreased after vaccination among the 3 less than 6 (P = 0.006) and 13 less than 18 (P = 0.001), but not among the 6 less than 13-year-olds. HLA-DQ2/8 positive children less than3 years decreased from 54% (15/28) before and 68% (19/28) during, to 30% (9/30) after vaccination (P = 0.014). Regardless of age, DQ2/2; 2/X (n = 177) patients had lower frequency (P = 0.020) and levels (P = 0.042) of A/H1N1-HA antibodies compared with non-DQ2/2; 2/X (n = 964) patients. GADA frequency was 50% before, 60% during and 51% after vaccination (P = 0.009). ZnT8QA frequency increased from 30% before to 34% during and 41% after vaccination (P = 0.002). Our findings suggest that young (less than3 years) along with DQ2/2; 2/X patients were low responders to Pandemrix (R). As the proportion of DQ2/8 patients less than3 years of age decreased after vaccination and the frequencies of GADA and ZnT8QA were enhanced, it cannot be excluded that the vaccine affected clinical onset of type 1 diabetes.
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| 6. |
- La Torre, Daria, et al.
(författare)
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Decreased cord-blood phospholipids in young age-at-onset type 1 diabetes
- 2013
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 62:11, s. 3951-3956
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Tidskriftsartikel (refereegranskat)abstract
- Children developing type 1 diabetes may have risk markers already in their umbilical cord blood. It is hypothesized that the risk for type 1 diabetes at an early age may be increased by a pathogenic pregnancy and be reflected in altered cord-blood composition. This study used metabolomics to test if the cord-blood lipidome was affected in children diagnosed with type 1 diabetes before 8 years of age. The present case-control study of 76 index children diagnosed with type 1 diabetes before 8 years of age and 76 healthy control subjects matched for HLA risk, sex, and date of birth, as well as the mother's age and gestational age, revealed that cord-blood phosphatidylcholines and phosphatidylethanolamines were significantly decreased in children diagnosed with type 1 diabetes before 4 years of age. Reduced levels of triglycerides correlated to gestational age in index and control children and to age at diagnosis only in the index children. Finally, gestational infection during the first trimester was associated with lower cord-blood total lysophosphatidylcholines in index and control children. In conclusion, metabolomics of umbilical cord blood may identify children at increased risk for type 1 diabetes. Low phospholipid levels at birth may represent key mediators of the immune system and contribute to early induction of islet autoimmunity.
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| 7. |
- Gu, Gucci Jijuan, et al.
(författare)
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Elevated Serum GAD65 and GAD65-GADA Immune Complexes in Stiff Person Syndrome.
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Glutamic acid decarboxylase 65 (GAD65) and autoantibodies specific for GAD65 (GADA) are associated with autoimmune diseases including Stiff Person Syndrome (SPS) and Type 1 diabetes (T1D). GADA is recognized as a biomarker of value for clinical diagnosis and prognostication in these diseases. Nonetheless, it remains medically interesting to develop sensitive and specific assays to detect GAD65 preceding GADA emergence, and to monitor GADA-GAD65 immune complexes in blood samples. In the present study, we developed a highly sensitive proximity ligation assay to measure serum GAD65. This novel assay allowed detection of as little as 0.65 pg/ml GAD65. We were also able to detect immune complexes involving GAD65 and GADA. Both free GAD65 and GAD65-GADA levels were significantly higher in serum samples from SPS patients compared to healthy controls. The proximity ligation assays applied for detection of GAD65 and its immune complexes may thus enable improved diagnosis and better understanding of SPS.
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| 8. |
- Falorni, Alberto, et al.
(författare)
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Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program
- 2015
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:11, s. 1761-1770
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Tidskriftsartikel (refereegranskat)abstract
- Background: 21-Hydroxylase autoantibodies (21OHAb) are markers of an adrenal autoimmune process that identifies individuals with autoimmune Addison's disease (AAD). Quality and inter-laboratory agreement of various 21OHAb tests are incompletely known. The objective of the study was to determine inter-laboratory concordance for 21OHAb determinations. Methods: Sixty-nine sera from 51 patients with AAD and 51 sera from 51 healthy subjects were blindly coded by a randomization center and distributed to 14 laboratories that determined 21OHAb, either by an "in-house" assay (n=9) using in vitro-translated S-35-21OH or luciferase-labeled 21OH or a commercial kit with I-125-21OH (n=5). Main outcome measures were diagnostic accuracy of each participating laboratory and inter-laboratory agreement of 21OHAb assays. Results: Intra-assay coefficient of variation ranged from 2.6% to 5.3% for laboratories using the commercial kit and from 5.1% to 23% for laboratories using "in-house" assays. Diagnostic accuracy, expressed as area under ROC curve (AUC), varied from 0.625 to 0.947 with the commercial kit and from 0.562 to 0.978 with "in-house" methods. Cohen's. of inter-rater agreement was 0.603 among all 14 laboratories, 0.691 among "in-house" laboratories, and 0.502 among commercial kit users. Optimized cutoff levels, calculated on the basis of AUCs, increased the diagnostic accuracy of every laboratory (AUC >0.9 for 11/14 laboratories) and increased the Cohen's. of inter-rater agreement. Discrepancies in quantitation of 21OHAb levels among different laboratories increased with increasing autoantibody levels. Conclusions: The quality of 21OHAb analytical procedures is mainly influenced by selection of cutoff value and correct handling of assay materials. A standardization program is needed to identify common standard sera and common measuring units.
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| 9. |
- Lind, Alexander, et al.
(författare)
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First trimester enterovirus IgM and beta cell autoantibodies in mothers to children affected by type 1 diabetes autoimmunity before 7 years of age
- 2018
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Ingår i: Journal of Reproductive Immunology. - : Elsevier BV. - 0165-0378. ; 127, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Background: Autoimmune (type 1) diabetes (T1D) is a frequent chronic disease in children and adolescents globally. Gestational enterovirus (EV) infections have been associated with an increased risk for T1D in the offspring. We test the hypothesis that EV infections during the first trimester were associated with beta cell autoantibodies in mothers of children who developed islet autoantibodies before 7 years of age. Materials and methods: Local registries were used to identify mothers to children born 2000–2007 who developed either beta cell autoantibodies or T1D during follow up. Serum samples from the first trimester were located in the Biobank. A total of 448 index mothers were identified and compared to 891 matched control mothers. EV-IgM was determined in a capture enzyme immunoassay. Beta cell autoantibodies were analyzed in standard radio binding assays. Results: The frequency of EV-IgM in index mothers was 20% (89/448), which did not differ from the control mothers 20% (175/891) (p = 0.922). Index mothers had multiple beta cell autoantibodies more often than control mothers (p = 0.037). Beta cell autoantibodies were increased during the November–April winter months in index compared to control mothers (p = 0.022). The observed difference was possibly explained by the months of February-April (p = 0.014). Concomitant EV-IgM and beta cell autoantibodies tended to be more common among index compared to control mothers (p = 0.039). Conclusion: EV-IgM during the first trimester may be associated with beta cell autoantibodies in mothers to children who developed either beta cell autoantibodies or T1D before 7 years of age.
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| 10. |
- Wallenius, Madeleine, et al.
(författare)
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Autoantibodies in Pandemrix®-induced narcolepsy : Nine candidate autoantigens fail the conformational autoantibody test
- 2019
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Ingår i: Autoimmunity. - : Informa UK Limited. - 0891-6934 .- 1607-842X. ; 52:4, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- Study objectives: Narcolepsy type 1 (NT1) is a chronic sleep disorder characterized by loss of hypocretin-producing neurons. Increased NT1 incidence was observed in Sweden following mass-vaccination with Pandemrix®. Genetic association to HLA DQB1*06:02 implies an autoimmune origin, but target autoantigen remains unknown. Candidate autoantigens for NT1 have previously been identified in solid-phase immunoassays, while autoantibodies against conformation-dependent epitopes are better detected in radiobinding assays. The aims are to determine autoantibody levels against nine candidate autoantigens representing (1) proteins of the hypocretin transmitter system; Preprohypocretin (ppHypocretin), Hypocretin peptides 1 and 2 (HCRT1 and HCRT2) and Hypocretin receptor 2 (HCRTR2); (2) proteins previously associated with NT1; Tribbles homologue 2 (TRIB2), Pro-opiomelanocortin/alpha-melanocyte-stimulating-hormone (POMC/α-MSH) and Prostaglandin D2 Receptor DP1 (DP1); (3) proteins suggested as autoantigens for multiple sclerosis (another HLA DQB1*06:02-associated neurological disease); ATP-dependent Inwardly Rectifying Potassium Channel Kir4.1 (KIR4.1) and Calcium-activated chloride channel Anoctamin 2 (ANO2). Methods: Serum from post-Pandemrix® NT1 patients (n = 31) and their healthy first-degree relatives (n = 66) were tested for autoantibody levels in radiobinding assays separating autoantibody bound from free labelled antigen with Protein A-Sepharose. 125I-labelled HCRT1 and HCRT2 were commercially available while 35S-methionine-labelled ppHypocretin, HCRTR2, TRIB2, α-MSH/POMC, DP1, KIR4.1 or ANO2 was prepared by in vitro transcription translation of respective cDNA. In-house standards were used to express data in arbitrary Units/ml (U/ml). Results: All radiolabelled autoantigens were detected in a concentration-dependent manner by respective standard sera. Levels of autoantibodies in the NT1 patients did not differ from healthy first-degree relatives in any of the nine candidate autoantigens. Conclusions: None of the nine labelled proteins proposed to be autoantigens were detected in the radiobinding assays for conformation-dependent autoantibodies. The results emphasise the need of further studies to identify autoantigen(s) and clarify the mechanisms in Pandemrix®-induced NT1.
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