Linda Åkerman

Long-Lasting Immune Responses 4 Years after GAD-Alum Treatment in Children with Type 1 Diabetes

A phase II clinical trial with glutamic acid decarboxylase (GAD) 65 formulated with aluminium hydroxide (GAD-alum) has shown efficacy in preserving residual insulin secretion in children and adolescents with recent-onset type 1 diabetes (T1D). We have performed a 4-year follow-up study of 59 of the original 70 patients to investigate long-term cellular and humoral immune responses after GAD-alum-treatment. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with GAD65. Frequencies of naïve, central and effector memory CD4+ and CD8+ T cells were measured, together with cytokine secretion, proliferation, gene expression and serum GAD65 autoantibody (GADA) levels. We here show that GAD-alum-treated patients display increased memory T-cell frequencies and prompt T-cell activation upon in vitro stimulation with GAD65, but not with control antigens, compared with placebo subjects. GAD65-induced T-cell activation was accompanied by secretion of T helper (Th) 1, Th2 and T regulatory cytokines and by induction of T-cell inhibitory pathways. Moreover, post-treatment serum GADA titres remained persistently increased in the GAD-alum arm, but did not inhibit GAD65 enzymatic activity. In conclusion, memory T- and B-cell responses persist 4 years after GAD-alum-treatment. In parallel to a GAD65-induced T-cell activation, our results show induction of T-cell inhibitory pathways important for regulating the GAD65 immunity.

GAD‐treatment of children and adolescents with recent‐onset type 1 diabetes preserves residual insulin secretion after 30 months

This study aimed to analyse data from two different studies (phase II and phase III) regarding the safety and efficacy of treatment with alum formulated glutamic acid decarboxylase GAD65 (GAD‐alum) at 30 months after administration to children and adolescents with type 1 diabetes.

Cellular and Humoral Immune Responses in Type 1 Diabetic Patients Participating in a Phase III GAD-alum Intervention Trial

OBJECTIVE GAD formulated in aluminum hydroxide (GAD-alum) has previously been shown to induce preservation of residual insulin secretion in recent-onset type 1 diabetes, but recent phase II and III GAD-alum trials failed to reach primary outcomes. The European phase III study was therefore closed after 15 months, and only a minority of patients completed the 30 months of follow-up. RESEARCH DESIGN AND METHODS This study aimed to characterize cellular and humoral responses in the Swedish patients (n = 148) participating in the phase III trial, receiving four (4D) or two (2D) GAD-alum doses or placebo. Serum GAD65 antibody (GADA) levels, GADA IgG1–4 subclass distribution, cytokine secretion, and proliferative responses in peripheral blood mononuclear cells (PBMCs) were analyzed. RESULTS The GAD65-induced cytokine profile tended to switch toward a predominant Th2-associated profile over time both in the 2D and 4D group. The groups also displayed increased GADA levels and PBMC proliferation compared with placebo, whereas GADA IgG subclass distribution changed in 4D patients. CONCLUSIONS Both 2D and 4D patients displayed GAD65-specifc cellular and humoral effects after GAD-alum treatment, but at different time points and magnitudes. No specific immune markers could be associated with treatment efficacy.

Regulatory T cell phenotype and function 4 years after GAD–alum treatment in children with type 1 diabetes

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+CD25–CD127+) 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.

Low C-peptide levels and decreased expression of TNF and CD45 in children with high risk of type 1 diabetes

Type 1 diabetes (T1D) patients have numeral and functional defects in peripheral immune cells, but the pre-diabetic period is fairly uncharacterized. Our aim was to analyze expression of immunological markers in T1D high risk children and relate it to clinical/immunological parameters. Children from ABIS (All Babies in Southeast Sweden) with ≥2 diabetes related autoantibodies were considered at high risk. Age-matched controls and new-onset T1D patients were included. Expression of genes related to immune cell function and different arms of the immune system was assessed in peripheral blood mononuclear cells using PCR array. Risk children had lower TNF and CD45, and although there were few differences between the groups, expression of many genes differed when comparing children with regard to residual insulin secretion. Hence, expression of immune related genes seemed related not only to the autoimmune process but rather to residual β-cell function, which was decreased already during the pre-diabetic phase.

Characteristics of the pre-diabetic period in children with high risk of type 1 diabetes recruited from the general Swedish population-The ABIS study

There is a need for increased understanding of the pre‐diabetic period in individuals with high risk of type 1 diabetes from the general population.

GAD-specific T cells are induced by GAD-alum treatment in Type-1 diabetes patients

Administration of Glutamic Acid Decarboxylase (GAD)65 formulated in aluminium hydroxide preserved insulin secretion in a phase II trial in recent onset Type 1 Diabetes. A subsequent European phase III trial was closed at 15months after failing to reach primary endpoint, but the majority of the Swedish patients completed the 21months follow-up. We studied the frequencies and phenotype of T cells, suppressive capacity of Tregs, GAD65-induced proliferation, and frequencies of T cells with a GAD65-specific TCR in Swedes participating in the trial. Stimulation with GAD65 induced activated T cells and also cells with a suppressive phenotype. Activated GAD65-specific effector T cells were detected by tetramer staining while the frequency of GAD65-specific Treg was not affected by the treatment. Additional doses of GAD-alum increased frequencies of CD25+CD127+, but had no effect on CD25hiCD127lo. Our findings indicate that GAD-alum treatment primarily induced activated T cells. GAD65-specific cells were mainly of activated phenotype.

Serum miRNA levels are related to glucose homeostasis and islet autoantibodies in children with high risk for type 1 diabetes

Micro RNAs (miRNAs) are promising disease biomarkers due to their high stability. Their expression in serum is altered in type 1 diabetes, but whether deviations exist in individuals with high risk for type 1 diabetes remains unexplored. We therefore assessed serum miRNAs in high-risk individuals (n = 21) positive for multiple islet autoantibodies, age-matched healthy children (n = 17) and recent-onset type 1 diabetes patients (n = 8), using Serum/Plasma Focus microRNA PCR Panels from Exiqon. The miRNA levels in the high-risk group were similar to healthy controls, and no specific miRNA profile was identified for the high-risk group. However, serum miRNAs appeared to reflect glycemic status and ongoing islet autoimmunity in high-risk individuals, since several miRNAs were associated to glucose homeostasis and autoantibody titers. High-risk individuals progressing to clinical disease after the sampling could not be clearly distinguished from non-progressors, while miRNA expression in the type 1 diabetes group deviated significantly from high-risk individuals and healthy controls, perhaps explained by major metabolic disturbances around the time of diagnosis.

Physical Activity, Blood Glucose and C-Peptide in Healthy School-Children, a Longitudinal Study

Aim To further elucidate the relationship between physical activity and several risk factors for development of diabetes (glucose, C-peptide and obesity) over time. Methods A prospective longitudinal study where physical activity was measured on 199 children from Kalmar and Linköping at age 8, and the same 107 children from Linköping again at age 12. Anthropometric data was collected and blood was analyzed for C-peptide and f-glucose. The children in the study were representative for the general Swedish child population, and on an average lean. Results High physical activity was related to lower C-peptide at age 8 and 12. This correlation was especially pronounced in boys, who also were more physically active than girls at both time points. The association seen at 8 years of age was similar at age 12 in most children. Children with higher BMI Z-Score had a higher fasting C-peptide (age 12) but linear regression showed that children with more steps per day were less likely to have a higher fasting C-peptide irrespective of BMI. Longitudinal follow-up showed that a decrease in physical activity increased insulin resistance and β-cell load. Conclusions Already in young children, physical activity improves insulin sensitivity and decreases the need of C-peptide over time. This seems to become even more pronounced with increasing age when children are followed longitudinally. Low physical activity increases the load on insulin producing β-cells, might increase the risk for both type 1- and 2 diabetes.