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Reign in Blood: Immune Regulation in Type 1 Diabetes
Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Type 1 Diabetes (T1D) is an autoimmune disease resulting in insulin deficiency as a result ofautoimmune destruction of pancreatic β-cells. Preserving β-cell function in patients with T1D would be of great benefit since patients with sustained endogenous insulin secretion are known to suffer less from secondary complications due to hyperglycemia. Glutamic acid decarboxylase 65 (GAD65) is a major autoantigen targeted by self-reactive lymphocytes in T1D, and has been used in several attempts at treating T1D by inducing tolerance to β-cell antigens. We showed positive clinical effects of GAD65 formulated with aluminium hydroxide (GAD-alum) on preservation of C-peptide secretion in a phase II clinical trial. Unfortunately, a phase III clinical trial in a larger population failed to confirm this finding. Regulatory T cells (Treg) are instrumental in maintaining peripheral tolerance to self-antigens. Deficiencies in Treg function are thought to influence the pathogenesis of autoimmune diseases, including T1D. One proposed mechanism of achieving tolerance to β-cell antigens in T1D is the induction of antigen-specific Treg through immunomodulation. The general aim of this thesis was to study immune regulation in T1D, the role of Treg and immunomodulatory effects of GAD-alum treatment in particular. Our hypothesis was that Treg biology is altered in T1D and pre-diabetes, and that an induction of GAD65-specific Treg contributes to the clinical efficacy of GAD-alum treatment. We demonstrated that T cells expressing Treg-associated markers were increased in number in patients with recent-onset T1D, as well as in children with high risk of developing T1D. We found that antigen recall 4 years after GAD-alum treatment induced cells with both regulatory and effector phenotypes in GAD-alum treated patients. Furthermore there was no effect on Treg-mediated suppression in GAD-alum treated patients, while patients with T1D, regardless of treatment, exhibited deficient Treg-mediated suppression of Teff that was intrinsic to the Treg population. We followed patients participating in a phase III trial of GAD-alum, and using an extended antibody panel we demonstrated that antigen recall induced mainly Teff cells in treated patients, along  with increased frequencies of memory T cells, non-suppressive CD45RA-FOXP3lo cells and increased GAD65-induced proliferation of mainly Teff and memory T cells. Finally we examined whether SNPs in genes encoding inflammasome components contributed to T1D risk, but found no effects of variant alleles on the risk of developing T1D, or on the efficacy of GAD-alum treatment. We show small effects on C-peptide secretion and autoantibody positivity in patients with T1D. In conclusion, we find that while Treg are deficient in patients with T1D, induction of Treg is an unlikely mechanism of action of GAD-alum treatment.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. , 113 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1377
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-98250DOI: 10.3384/diss.diva-98250ISBN: 978-91-7519-533-9 (print)OAI: oai:DiVA.org:liu-98250DiVA: diva2:653604
Public defence
2013-11-08, Berzeliussalen, Campus US, Linköpings universitet, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2013-10-04 Created: 2013-10-04 Last updated: 2013-10-07Bibliographically approved
List of papers
1. Increased expression of regulatory T cell-associated markers in recent-onset diabetic children
Open this publication in new window or tab >>Increased expression of regulatory T cell-associated markers in recent-onset diabetic children
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2011 (English)In: Open Journal of Immunology, ISSN 2162-450X, E-ISSN 2162-4526, Vol. 1, no 3, 57-64 p.Article in journal (Refereed) Published
Abstract [en]

CD4+CD25hi T cells are thought to be crucial for the maintenance of immunological tolerance to self antigens. In this study, we investigated the frequencies of these cells in the early stage of type 1 diabetes, as well as in a setting of possible pre-diabetic autoimmunity. Hence, the expression of FOXP3, CTLA-4, and CD27 in CD4+ CD25hi T cells was analyzed using flow cytometry in 14 patients with recent onset type 1 diabetes, in 9 at-risk individuals, and 9 healthy individuals with no known risk for type 1 diabetes. Our results show there were no differences in the frequency of CD4+CD25hi cells between groups. However, compared to controls, recent-onset type 1 diabetic patients had higher expression of FOXP3, CTLA-4, and CD27 in CD4+ CD25hi cells from peripheral blood. The median fluorescence intensity of FOXP3 was significantly higher in CD4+CD25hi cells from patients with type 1 diabetes than from controls. Furthermore, a positive correlation between the frequency of FOXP3+ cells and the median fluorescence intensity of FOXP3 was observed among patients with type 1 diabetes. These data suggest that the frequency of CD4+CD25hi FOXP3+ T cells in the periphery is not decreased but rather increased at onset of type 1 diabetes. Thus, functional deficiencies rather than reduced numbers of CD4+CD25hi cells could contribute to the development of type 1 diabetes. 

Place, publisher, year, edition, pages
Irvine, CA. USA: Scientific Research Publishing, 2011
Keyword
Regulatory T cells; Type 1 Diabetes; Autoantibodies
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-75890 (URN)10.4236/oji.2011.13007 (DOI)
Available from: 2012-03-15 Created: 2012-03-15 Last updated: 2017-12-07
2. Regulatory T cell phenotype and function 4 years after GAD–alum treatment in children with type 1 diabetes
Open this publication in new window or tab >>Regulatory T cell phenotype and function 4 years after GAD–alum treatment in children with type 1 diabetes
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2013 (English)In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 172, no 3, 394-402 p.Article in journal (Refereed) Published
Abstract [en]

Glutamic acid decarboxylase (GAD)65 formulated with aluminium hydroxide (GAD-alum) was effective in preserving insulin secretion in a Phase II clinical trial in children and adolescents with recent-onset type 1 diabetes. In addition, GAD-alum treated patients increased CD4+CD25hi forkhead box protein 3+ (FoxP3+) cell numbers in response to in-vitro GAD65 stimulation. We have carried out a 4-year follow-up study of 59 of the original 70 patients to investigate long-term effects on the frequency and function of regulatory T cells after GAD-alum treatment. Peripheral blood mononuclear cells were stimulated in vitro with GAD65 for 7 days and expression of regulatory T cell markers was measured by flow cytometry. Regulatory T cells (CD4+CD25hiCD127lo) and effector T cells (CD4+CD25CD127+) were further sorted, expanded and used in suppression assays to assess regulatory T cell function after GAD-alum treatment. GAD-alum-treated patients displayed higher frequencies of in-vitro GAD65-induced CD4+CD25+CD127+ as well as CD4+CD25hiCD127lo and CD4+FoxP3+ cells compared to placebo. Moreover, GAD65 stimulation induced a population of CD4hi cells consisting mainly of CD25+CD127+, which was specific of GAD-alum-treated patients (16 of 25 versus one of 25 in placebo). Assessment of suppressive function in expanded regulatory T cells revealed no difference between GAD-alum- and placebo-treated individuals. Regulatory T cell frequency did not correlate with C-peptide secretion throughout the study. In conclusion, GAD-alum treatment induced both GAD65-reactive CD25+CD127+ and CD25hiCD127lo cells, but no difference in regulatory T cell function 4 years after GAD-alum treatment.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2013
Keyword
CD4 T cells (T helper, Th0, Th1, Th2, Th3, Th17), diabetes, immune regulation, regulatory T cells (Treg), therapy/immunotherapy
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-93379 (URN)10.1111/cei.12078 (DOI)000318073000004 ()
Note

Funding Agencies|Swedish Research Council|K2008-55x-20652-01-3|Swedish Child Diabetes Foundation (Barndiabetesfonden)||Medical Research Council of Southeast Sweden||JDRF|1-2008-106|Ile-de-France CODDIM||Inserm Avenir Program||

Available from: 2013-05-31 Created: 2013-05-31 Last updated: 2017-12-06Bibliographically approved
3. GAD-alum treatment induces GAD-specific CD4 T cells in a phase III clinical trial
Open this publication in new window or tab >>GAD-alum treatment induces GAD-specific CD4 T cells in a phase III clinical trial
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2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Glutamic Acid Decarboxylase (GAD)65 formulated in aluminium hydroxide (GAD-alum preserved insulin secretion in a phase II clinical trial in recent onset type 1 diabetes. GADalum treated patients up-regulated FOXP3 upon antigen recall at 21 and 30 months after treatment. A 4-year follow-up of the study revealed increased frequencies of both CD25+CD127+ and CD25hiCD127lo cells in treated patients after antigen recall. A subsequent european phase III trial was closed after 15 months after failing to reach primary outcome. We monitored antigen recall induced frequencies of memory, effector and regulatory T cells throughout the phase III trial. Antigen recall induced mainly CD25+CD127+, CD45RO+ and non-suppressive FOXP3loCD45RA- cells in GAD-alum treated patients. In addition, a population of activated FSChiSSChi cells was observed, enriched in CD25+CD127+, CD45RO+ and proliferating cells. GAD65-specific T cells determined by tetramer staining were induced by antigen recall in GAD-alum treated patients and were more frequent in the FSChiSSChi population. Additional doses of GAD-alum increased frequencies of CD25+CD127+, CD45RO+ and FSChiSSChi cells but had no effect on frequencies of CD25hiCD127lo. Our findings indicate that antigen recall after GAD-alum treatment primarily induces memory and activated T cells. In particular, GAD65-specific cells were mainly of a memory or activated phenotype. Additional doses of GAD-alum mainly affect memory T cell frequency and T cell activation.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-98251 (URN)
Available from: 2013-10-04 Created: 2013-10-04 Last updated: 2013-10-04
4. Polymorphisms in NALP3 inflammasome components NLRP3 and CARD8 affect C-peptide secretion in type 1 diabetes
Open this publication in new window or tab >>Polymorphisms in NALP3 inflammasome components NLRP3 and CARD8 affect C-peptide secretion in type 1 diabetes
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2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Interleukin-1β has long been known to have potential roles in type 1 diabetes (T1D) pathogenesis. Production of active Iinterleukin-1β is dependent on the action of a caspase activating protein complex called NALP3 inflammasome. The NALP3 inflammasome is composed of NALP3/Cryopyrin, ASC and CARD8. Polymorphisms in the NLRP3 and CARD8 genes have been linked to several autoinflammatory diseases. The NALP3 inflammasome is crucial for adjuvanticity of aluminium hydroxide, which is used as adjuvant in clinical trials of glutamic acid decarboxylase (GAD)-alum in T1D. Our aim was to investigate the effect of common polymorphisms of NLRP3 on T1D susceptibility as well as on GAD-alum treatment efficacy. The single nucleotide polymorphisms NLRP3 Q705K, CARD8 C10X and an SNP downstream of the NLRP3 gene, rs10733113, were genotyped using a Taqman genotyping assay. The A allele of CARD8 C10X was associated with a lower stimulated insulin secretion 3 months after diagnosis in males. Patients with at least one G allele at rs10733113 were more likely to produce auto-antibodies against two or more of the islet antigens GAD, Insulin or IA-2. None of the genotyped SNPs had any significant influence on efficacy of GAD-alum treatment, but individuals with at least one rs10733113 G allele treated with placebo had lower residual insulin secretion than those with the AA genotype at 9, 15 and 21 months after start of treatment.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-98248 (URN)
Available from: 2013-10-04 Created: 2013-10-04 Last updated: 2013-10-04Bibliographically approved

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