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GAD-alum treatment in patients with type 1 diabetes and the subsequent effect on GADA IgG subclass distribution, GAD(65) enzyme activity and humoral response
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2010 (English)In: Clinical Immunology, ISSN 1521-6616, E-ISSN 1521-7035, Vol. 137, no 1, 31-40Artikel i tidskrift (Refereed) Published
Abstract [en]

We have previously shown that two injections of 20 mu g GAD-alum to recent onset type 1 diabetic children induced GADA levels in parallel to preservation of insulin secretion. Here we investigated if boosted GADA induced changes in IgG1, 2, 3 and 4 subclass distributions or affected GAD(65) enzyme activity. We further studied the specific effect of GAD-alum through analyses of IA-2A, tetanus toxoid and total IgE antibodies. Serum from children receiving GAD alum or placebo was collected pre-treatment and after 3, 9, 15 and 21 months. At 3 months a reduced percentage of IgG1 and increased IgG3/IgG4 were detected in GAD-alum treated. Further, IA-2A, IgE and tetanus toxoid antibodies, as well as GAD(65) enzyme activity, were unaffected confirming the specific effect of treatment. In the GAD-alum group, higher pretreatment GADA were associated to more pronounced C-peptide preservation. The induced IgG3/IgG4 and reduced IgG1 suggest a Th2 deviation of the immune response.

Keyword [en]
Immunotherapy, GAD(65), GAD-alum, GADA, Type 1 diabetes, T1D, IgG, IgG subclass
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-60511 (URN)10.1016/j.clim.2010.06.001 (DOI)000282204900005 (ISI)oai:DiVA.org:liu-60511 (OAI)
Note

Original Publication: Mikael Chéramy, Camilla Skoglund, Ingela Johansson, Johnny Ludvigsson, Christiane S Hampe and Rosaura Casas, GAD-alum treatment in patients with type 1 diabetes and the subsequent effect on GADA IgG subclass distribution, GAD(65) enzyme activity and humoral response, 2010, CLINICAL IMMUNOLOGY, (137), 1, 31-40. http://dx.doi.org/10.1016/j.clim.2010.06.001 Copyright: Elsevier Science B.V., Amsterdam http://www.elsevier.com/

Available from2010-10-15 Created:2010-10-15 Last updated:2013-09-12Bibliographically approved
In thesis
1. Autoantibodies related to type 1 diabetes in children
Open this publication in new window or tab >>Autoantibodies related to type 1 diabetes in children
2011 (English)Doktorsavhandling, sammanläggning (Other academic)
Abstract [en]

Type 1 diabetes is an autoimmune disease resulting from destruction of the insulin producing beta cells in the pancreas. The patients need life-long heavy treatment and still complications, both acute and later in life, are common. The incidence of type 1 diabetes has increased rapidly during the last decades, especially among young children. The disease can be predicted by genes predisposing type 1 diabetes, mainly human leukocyte antigen (HLA) genes, together with presence of autoantibodies to beta-cell antigens, where multiple autoantibodies confer the highest risk. A number of immune system intervention trials are now ongoing aiming to halt the progression of the inflammatory process in the beta cells.

This thesis aimed to investigate the prevalence and levels of autoantibodies in healthy children and in children with type 1 diabetes. Another aim was to study different properties of one of these autoantibodies, such as to which epitopes the antibodies bind and the distribution of immunoglobulin (Ig)-G subclasses, after immunomodulatory treatment in children with type 1 diabetes.

We found that positivity to autoantibodies against glutamic acid decarboxylase (GADA) and tyrosine phosphatase like protein islet antigen-2 (IA-2A) was associated with HLA risk genotypes in 5-year old children from the general population. HLA risk genotypes seemed important for persistence of autoantibodies and for development of type 1 diabetes, while emergence of autoantibodies, especially transient autoantibodies, seemed to be more influenced by environmental factors. Improved methods for detection of autoantibodies are needed, for prediction of diabetes and for identification of high-risk individuals suitable for prevention treatments. Therefore, an assay for measurement of insulin autoantibodies (IAA), based on surface plasmon resonance (SPR), was developed. The main advantages of this method are that there is no need for labelling and that it is time-saving compared to the traditionally used radioimmunoassay (RIA), but further development of the method is needed.

Treatment with GAD-alum (Diamyd) in children with type 1 diabetes has shown to preserve residual insulin secretion. This clinical effect was accompanied by an increase in GADA levels. We investigated the epitope reactivity of GADA in both GAD-alum and placebo treated children, and found that binding to one of the tested epitopes was temporarily increased after injection of GAD-alum. This result suggests that the quality of GADA was, to some extent, transiently affected by the treatment. On the other hand, no changes in binding to epitopes associated with stiff person syndrome (SPS) were observed, which together with the lack of change in GAD65 enzyme activity further strengthens the safety of the treatment. We also observed that the distribution of IgG subclasses was changed by GAD-alum treatment, with a lower proportion of IgG1 and higher IgG3 and IgG4. Lower IgG1 and higher IgG4 suggest a temporary switch towards a protective Th2 immune response, which has previously been observed in the same individuals for other immunological markers.

In conclusion, measurement of autoantibodies related to type 1 diabetes is an important tool for studying the autoimmune process in pre-diabetic and type 1 diabetic children. In addition to the use as markers of disease progression, the autoantibodies may be used for studying the effects of immunomodulatory treatments on the humoral immune response.

Publisher, range
Linköping: Linköping University Electronic Press, 2011. 116 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1218
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-64593 (URN)978-91-7393-276-9 (ISBN)
Public defence
2011-02-18, Berzeliussalen, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 09:00 (English)
Opponent
Supervisors
Available from2011-01-28 Created:2011-01-28 Last updated:2011-01-28Bibliographically approved
2. Characteristics of GADA in Type 1 Diabetes following Immunomodulation with GAD65
Open this publication in new window or tab >>Characteristics of GADA in Type 1 Diabetes following Immunomodulation with GAD65
2012 (English)Doktorsavhandling, sammanläggning (Other academic)
Abstract [en]

Type 1 diabetes (T1D) is a serious autoimmune disease which increases worldwide and affects children at a young age, but there still is no cure available. Clinical intervention trials in recent onset T1D patients are therefore very important, since even a modest preservation of β-cell function has proven to reduce end-organ complications. Glutamic acid decarboxylase 65 (GAD65) is one of the major antigens in T1D, to which autoantibodies (GADA) are formed. Immunomodulation with aluminum-formulated GAD65 (GAD-alum) has been considered both in the prevention and intervention of T1D. In a phase II trial using GADalum we showed clinical benefits in C-peptide preservation, but unfortunately a following larger European phase III trial failed to reach primary end-point. The general aim of this thesis was to study the characteristics and phenotypes of GADA following immunomodulation with GAD-alum in T1D patients during a phase II and III trial.

In the phase II trial, a transient increase of the GADA IgG3 and IgG4 subclasses, and a decrease in IgG1 was detected as part of the treatment-induced GADA levels after 2 GADalum doses, a result interpreted to be T helper (Th) 2-associated. This Th2-associated immune response was also observed, in parallel to increased GADA levels, during the following phase III trial including a larger group of patients. However, enhanced Th2-like IgG subclass distribution, reflected as increased IgG4 frequency, was in contrast only observed in the group treated with 4 doses of GAD-alum. In addition, the GADA fold-change was associated with in vitro GAD65-stimulated cytokine secretion, but only in patients receiving 2 GAD-alum doses. Furthermore, a 4-year follow-up of the phase II trial showed that the effect of GAD-alum treatment was long-lasting as GADA titers remained elevated. Even though the phase III trial did not reach primary end-point, and was closed after 15 months, preservation of β-cell function was observed in the small sub-group of Swedish patients receiving 2 GAD-alum doses that completed the 30 months trial-period. During the trials, concerns were raised whether the elevated GADA titers might induce Stiff person syndrome (SPS), a disease affecting the nervous system, but in vitro analysis of GADA phenotypes showed that the GAD65-enzyme activity and GADA epitope distribution differed from that detected in SPS patients.

Continued research to clarify how immunomodulation with autoantigens affects immune responses and also to identify which patients are suitable for treatment, is crucial for optimizing future T1D intervention- and prevention trials.

Publisher, range
Linköping: Linköping University Electronic Press, 2012. 83 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1337
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-84842 (URN)978-91-7519-774-6 (ISBN)
Public defence
2012-11-15, Berzeliussalen, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 13:00 (English)
Opponent
Supervisors
Available from2012-10-24 Created:2012-10-24 Last updated:2012-10-30Bibliographically approved

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Chéramy, MikaelSkoglund, CamillaJohansson, IngelaLudvigsson, JohnnyHampe, Christiane SCasas, Rosaura
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