Prevention strategies for type 1 diabetes mellitus: current status and future directions

Fetal and Neonatal Illnesses Caused or Influenced by Maternal Transplacental IgG and/or Therapeutic Antibodies Applied During Pregnancy

The human fetus is protected by the mother’s antibodies. At the end of the pregnancy, the concentration of maternal antibodies is higher in the cord blood, than in the maternal circulation. Simultaneously, the immune system of the fetus begins to work and from the second trimester, fetal IgM is produced by the fetal immune system specific to microorganisms and antigens passing the maternal-fetal barrier. The same time the fetal immune system has to cope and develop tolerance and T_REG cells to the maternal microchimeric cells, latent virus-carrier maternal cells and microorganisms transported through the maternal-fetal barrier.

The maternal phenotypic inheritance may hide risks for the newborn, too. Antibody mediated enhancement results in dengue shock syndrome in the first 8 month of age of the baby.

A series of pathologic maternal antibodies may elicit neonatal illnesses upon birth usually recovering during the first months of the life of the offspring. Certain antibodies, however, may impair the fetal or neonatal tissues or organs resulting prolonged recovery or initiating prolonged pathological processes of the children.

The importance of maternal anti-idiotypic antibodies are believed to prime the fetal immune system with epitopes of etiologic agents infected the mother during her whole life before pregnancy and delivery.

The chemotherapeutical and biological substances used for the therapy of the mother will be transcytosed into the fetal body during the last two trimesters of pregnancy. The long series of the therapeutic monoclonal antibodies and conjugates has not been tested systematically yet. The available data are summarised in this chapter.

The innate immunity plays an important role in fetal defence. The concentration of interferon is relative high in the placenta. This is probably one reason, why the therapeutic interferon treatment of the mother does not impair the fetal development.

Current status of immunomodulatory and cellular therapies in preclinical and clinical islet transplantation

Clinical islet transplantation is a β-cell replacement strategy that represents a possible definitive intervention for patients with type 1 diabetes, offering substantial benefits in terms of lowering daily insulin requirements and reducing incidences of debilitating hypoglycemic episodes and unawareness. Despite impressive advances in this field, a limiting supply of islets, inadequate means for preventing islet rejection, and the deleterious diabetogenic and nephrotoxic side effects associated with chronic immunosuppressive therapy preclude its wide-spread applicability. Islet transplantation however allows a window of opportunity for attempting various therapeutic manipulations of islets prior to transplantation aimed at achieving superior transplant outcomes. In this paper, we will focus on the current status of various immunosuppressive and cellular therapies that promote graft function and survival in preclinical and clinical islet transplantation with special emphasis on the tolerance-inducing capacity of regulatory T cells as well as the β-cells regenerative capacity of stem cells.

Developing a Deeper Understanding of Autism: Connecting Knowledge through Literature Mining

In the field of autism, an enormous increase in available information makes it very difficult to connect fragments of knowledge into a more coherent picture. We present a literature mining method, RaJoLink, to search for matched themes in unrelated literature that may contribute to a better understanding of complex pathological conditions, such as autism. 214 full text articles on autism, published in PubMed, served as a source of data. Using ontology construction, we identified the main concepts of what is already known about autism. Then, the RaJoLink method, based on Swanson's ABC model, was used to reveal potentially interesting, but not yet investigated, connections between different concepts in research. Among the more interesting concepts identified with RaJoLink in our study were calcineurin and NF-kappaB. Both terms can be linked to neuro-immune abnormalities in the brain of patients with autism. Further research is needed to provide stronger evidence about calcineurin and NF-kappaB involvement in autism. However, the analysis presented confirms that this method could support experts on their way towards discovering hidden relationships and towards a better understanding of the disorder.

Prevention of Type 1 Diabetes Mellitus using a Novel Vaccine

Type 1 diabetes mellitus (T1DM) affects 1 in 300 people and the incidence of the disease is rising worldwide. T1DM is caused by chronic autoimmune destruction of the insulin-producing β-cells. The exact etiology and primary auto-antigen are not yet known. The autoimmune, chronic, and progressive nature of the disease raises the possibility of intervention, preferably by slowing down or stopping the destruction of the β-cells as early as the prediabetic stage. Since the 1980s, several attempts have been made to maintain β-cell function using immunosuppressive agents, immune modulation such as plasmapheresis, cytokine therapy, or antibody treatment. These agents were not diabetes specific; the occasionally observed beneficial effect did not compensate for the often very severe side effects. According to the latest assumption, the administration of diabetes-specific auto-antigens can elicit tolerance, which can prevent the destruction of the β-cells, hopefully without serious side effects. The authors summarize current understanding of the immunology of T1DM, review the trials on prevention, and discuss their vaccination study.

Approaches in type 1 diabetes research: A status report

Type 1 diabetes is a multifactorial disease with an early age of onset, in which the insulin producing beta cell of the pancreas are destroyed because of autoimmunity. It is the second most common chronic disease in children and account for 5% to 10% of all diagnosed cases of diabetes. India is having an incidence of 10.6 cases/year/100,000, and recent studies indicate that the prevalence of type 1 diabetes in India is increasing. However in view of poor health care network, there is no monitoring system in the country. Of the 18 genomic intervals implicated for the risk to develop type 1 diabetes, the major histocompatibility complex (MHC) region on chromosome 6p21.31 has been the major contributor estimated to account for 40-50%, followed by 10% frequency of INS-VNTR at 5' flanking region of the insulin gene on chromosome 11p15.5. However, population studies suggest that > 95% of type 1 diabetes have HLA-DR3 or DR4, or both, and in family studies, sibling pairs affected with type 1 diabetes have a non-random distribution of shared HLA haplotypes. As predisposing genetic factors such as HLA alleles are known, immunological interventions to prevent type 1 diabetes are of great interest. In the present study we have reviewed the status of molecular genetics of the disease and the approaches that need to be adopted in terms of developing patient and suitable control cohorts in the country.

Autoimmune polyendocrine syndrome type 1 (APS-1) as a model for understanding autoimmune polyendocrine syndrome type 2 (APS-2)

Autoimmune polyendocrine syndromes type 1 and 2 (APS-1 and APS-2) are diverse in regards to their component diseases and immunologic features of pathogenesis. Animal models and human studies highlight the importance of alleles of HLA (human leukocyte antigen)-like molecules determining tissue specific targeting that with the loss of tolerance leads to organ specific autoimmunity. Knowledge of the syndromes and component diseases allows clinicians to recognize and prevent illness prior to morbidity. With the current understanding of the syndromes, a paradigm for diagnosis, screening and treatment can be established. Once genetically susceptible individuals are identified screening for autoantibodies can be performed. Amongst autoantibody positive individuals, monitoring for physiologic decompensation, with a goal of treating prior to morbidity and in some cases mortality, follows. With continued basic and clinical research, therapies aimed at treating the underlying autoimmunity and disease prevention should become possible.

Prevention of diabetes: effect of mycophenolate mofetil and anti-CD25 on onset of diabetes in the DRBB rat

BACKGROUND

Anti-CD25 and mycophenolate mofetil (MMF) treatment of patients with new-onset diabetes is currently being tested as one of the trials in TrialNet. We tested the effectiveness of MMF and anti-CD25 in preventing autoimmune diabetes in the diabetes-resistant biobreeding (DRBB) rat.

METHODS

Autoimmune diabetes in the DRBB rat was induced with a Treg cell depletion regimen starting at 24-26 d of age. Treatment was started on the first day of the depletion regimen in the following groups: (i) control (vehicle); (ii) MMF 25 mg/kg/d intramuscularly daily for 8 wk; (iii) anti-CD25 0.8 mg/kg/d intraperitoneally 5 d/wk for 3 wk; and (iv) combination of MMF and anti-CD25. In a second set of experiments, treatments were started on day 5 of the depletion regimen (delayed treatment) with groups 1, 3, and 4. Rats that had diabetes-free survival for at least 30 d after the treatment was stopped underwent a second Treg depletion (redepletion).

RESULTS

In each of the three treatment groups (n = 10/group), onset of diabetes was delayed or prevented in 20, 40 and 80% in groups 2, 3, and 4, respectively. After redepletion, diabetes-free survival was unchanged in group 2 and decreased to 10 and 30% in groups 3 and 4, respectively. With delayed treatment, groups 3 and 4 had 33 and 50% diabetes-free survival that decreased to 0 and 33% after redepletion.

SUMMARY

MMF and anti-CD25 alone or in combination are effective in delaying and preventing diabetes in the DRBB rat especially if treatment is started before stimulation and expansion of the autoreactive T cells.

Diets rich in polyphenols and vitamin A inhibit the development of type I autoimmune diabetes in nonobese diabetic mice

Type I juvenile diabetes mellitus is characterized by the infiltration of activated T lymphocytes and monocytes into the islets of Langerhans of the pancreas, resulting in inflammation and progressive destruction of the insulin-producing beta cells. We hypothesized that feeding nonobese diabetic (NOD) mice diets rich in polyphenols or vitamin A, both known modulators of immune function, would decrease the autoimmune inflammatory process associated with type I diabetes. NOD mice were fed a control diet (C) and diets containing either 1% freeze-dried grape powder (GP) or 250 IU vitamin A/g (VA; 0.262 micromol retinyl acetate/g) of food. Mice were considered diabetic and killed when blood glucose reached 13.9 mmol/L or greater. By approximately 7 mo of age, 71% of C mice progressed to diabetes. Incidence of diabetes was reduced to 33% (P < 0.05) and 25% (P < 0.05) in mice receiving 1% dietary grape powder and VA, respectively. Splenocytes from mice receiving both GP and VA had lower TNF-alpha production after LPS stimulation than C mice (P < 0.05). Histological analysis of pancreatic tissue showed a significant reduction in the severity of insulitis in the mice receiving GP and VA compared with C mice. These data suggest that diets rich in polyphenols or vitamin A have protective effects against autoimmune inflammatory attack of the islet beta cells and have the potential to reduce the onset and pathogenesis of autoimmune diabetes.

Costimulation and autoimmune diabetes in BB rats

Costimulatory signals regulate T-cell activation. To investigate the role of costimulation in autoimmunity and transplantation, we studied the BB rat model of type 1 diabetes. Diabetes-prone BB (BBDP) rats spontaneously develop disease when 55-120 days of age. We observed that two anti-CD28 monoclonal antibodies (mAb) with different functional activities completely prevented diabetes in BBDP rats. Anti-CD154 mAb delayed diabetes, whereas treatment with CTLA4-Ig or anti-CD80 mAb accelerated disease. Anti-CD86 or anti-CD134L mAbs had no effect. Diabetes resistant BB (BBDR) rats are disease-free, but >95% of them develop diabetes after treatment with polyinosinic-polycytidylic acid and an mAb that depletes Treg cells. In the induced BBDR model, anti-CD154 mAb delayed onset of diabetes, whereas CTLA4-Ig, anti-CD134L or either of the anti-CD28 mAbs had little or no effect. In contrast, blockade of the CD134-CD134L pathway was highly effective for preventing autoimmune recurrence against syngeneic islet grafts in diabetic BBDR hosts. Blockade of the CD40-CD154 pathway was also effective, but less so. These data suggest that the effectiveness of costimulation blockade in the treatment of type 1 diabetes is dependent on both the costimulatory pathway targeted and the mechanism of induction, stage, intensity and duration of the pathogenic process.

VEGF gene variability and type 1 diabetes: evidence for a protective role

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine originally described as an angiogenic factor. A number of reports have recently demonstrated that VEGF increases pancreatic islet survival after islet transplantation by stimulating angiogenesis and improving islet revascularization. Whether VEGF can protect from the autoimmune destruction of insulin-producing beta-cells that characterizes the development of type 1 diabetes is presently unknown. To clarify this issue, we studied the association of three polymorphisms of the promoter region of VEGF with type 1 diabetes in the Italian and the Finnish populations. The polymorphisms considered [C(-2578)A, G(-1190)A, and G(-1154)A] are known to modulate in vitro and in vivo VEGF expression. We found that VEGF promoter genotypes are associated with type 1 diabetes in both populations, but with different combinations. In Italian individuals, the -2578AA and -1190AA genotypes are associated with type 1 diabetes and accelerate its onset, while in Finnish individuals, -1154GG and -1190GG protect from type 1 diabetes and delay its onset. In conclusion, because the expected functional consequence of both genotype combinations is a reduced VEGF expression in diabetic patients, we propose a protective role of VEGF in the development of type 1 diabetes.

Contribution of peptides to multiple sclerosis research

Multiple sclerosis (MS) is an autoimmune disease associated with chronic inflammatory demyelination of the central nervous system in genetically susceptible individuals. Because of the disease complexity and heterogeneity, its pathogenesis remains unknown despite extensive research efforts, and specific effective treatments have not yet been developed. Peptide-based research has been important in attempts to unravel particular aspects of this complex disease, including the characterization of the different molecular mechanisms of MS, with the goal of providing useful products for immune-mediated therapies. In fact, in the past decade, peptide-based research has been predominant in research aimed to identify and/or develop target antigens as synthetic probes for specific biomarkers as well as innovative immunomodulating therapies. This review presents an overview of the contributions of peptide science to MS research and discusses future directions of peptide-based investigations.

Lack of effect of intermittently administered sodium fusidate in patients with newly diagnosed type 1 diabetes mellitus: the FUSIDM trial

AIMS/HYPOTHESIS

We evaluated in a double-blind study the effect of early treatment with the immunomodulatory drug fusidin in patients with newly diagnosed type 1 diabetes mellitus.

METHODS

Twenty-eight adults with newly diagnosed type 1 diabetes were included in the study. The patients were randomly assigned (computer-generated random number sequence) to two experimental groups. Patients allocated to the fusidin (FUS) group (n=15) received sodium fusidate (fusidin; 500 mg orally three times daily for 4 weeks). Subsequently the drug was given at the same dose and scheduled for two consecutive weeks a month followed by 2 weeks a month without the drug for 20 weeks. Subjects allocated to the placebo (PCB) group (n=13) received placebo according to the same schedule and conditions described for sodium fusidate in the FUS group. All patients received a diet adjusted to their age and BMI, and intensive insulin therapy.

RESULTS

There were no statistically significant differences between the FUS and PCB groups in beta cell function, evaluated by basal and glucagon-stimulated C-peptide values during the follow-up (24 and 48 weeks). There was also no difference between the two groups in insulin requirement after 48 weeks (0.4+/-0.2 and 0.4+/-0.2 U/kg body weight for the FUS and PCB groups, respectively). Antibody titres, including insulin autoantibodies, were similar in the two groups during the follow-up.

CONCLUSIONS/INTERPRETATION

Early treatment of newly diagnosed type 1 diabetes patients with intermittently administered fusidin failed to influence the natural course of the disease.

Therapeutic peptidomimetic strategies for autoimmune diseases: costimulation blockade*

Cognate interactions between immune effector cells and antigen-presenting cells (APCs) govern immune responses. Specific signals occur between the T-cell receptor peptide and APCs and nonspecific signals between pairs of costimulatory molecules. Costimulation signals are required for full T-cell activation and are assumed to regulate T-cell responses as well as other aspects of the immune system. As new discoveries are made, it is becoming clear how important these costimulation interactions are for immune responses. Costimulation requirements for T-cell regulation have been extensively studied as a way to control many autoimmune diseases and downregulate inflammatory reactions. The CD28:B7 and the CD40:CD40L families of molecules are considered to be critical costimulatory molecules and have been studied extensively. Blocking the interaction between these molecules results in a state of immune unresponsiveness termed 'anergy'. Several different strategies for blockade of these interactions are explored including monoclonal antibodies (mAbs), Fab fragments, chimeric, and/or fusion proteins. We developed novel, immune-specific approaches that interfere with these interactions. Using experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis mediated by central nervous system (CNS)-specific T-cells, we developed a multi-targeted approach that utilizes peptides for blockade of costimulatory molecules. We designed blocking peptide mimics that retain the functional binding area of the parent protein while reducing the overall size and are thus capable of blocking signal transduction. In this paper, we review the role of costimulatory molecules in autoimmune diseases, two of the most well-studied costimulatory pathways (CD28/CTLA-4:B7 and CD40:CD40L), and the advantages of peptidomimetic approaches. We present data showing the ability of peptide mimics of costimulatory molecules to suppress autoimmune disease and propose a mechanism for disease suppression.

ADA Outstanding Scientific Achievement Lecture 2004. Thirty years of investigating the autoimmune basis for type 1 diabetes: why can't we prevent or reverse this disease?

Thirty years ago, a convergence of investigational observations lead to the now widely accepted notion that type 1 diabetes results from an autoimmune destruction of insulin-producing beta-cells in subjects genetically predisposed to the disease. Improvements in understanding of the natural history of type 1 diabetes, the biochemical identification of autoantigens, the discovery of spontaneous animal models for the disease, the availability of immune-modulating agents, and other important facets, including disease prediction, drove an early sense of optimism that the prevention of type 1 diabetes was possible and, in some research circles, that ability was thought to be within a not-to-distant reach. Unfortunately, those early expectations proved overly optimistic, and despite the aforementioned knowledge gains, the generation of improved investigational tools, the identification of methods to prevent the disease in animal models, and the formation of very large disease prevention trials, a means to prevent type 1 diabetes in humans continues to remain elusive. Believing in the concept of "informative failures" (a.k.a., wise people learn from their mistakes), this lecture reviews the knowledge base collected over this time period and, when combined with an analysis of those research experiences, sets forth a proposal for future investigations that will, hopefully, turn discoveries into a means for the prevention or reversal of type 1 diabetes.

Polyclonal anti-T-cell therapy for type 1 diabetes mellitus of recent onset

The destruction of pancreatic beta-cells in type 1 diabetes mellitus is mediated by autoreactive T-lymphocyte clones. We initiated a prospective randomized controlled trial of polyclonal rabbit anti-T-cell globulin (ATG) in patients with type 1 diabetes within 4 weeks of diagnosis and with residual post-glucagon C-peptide levels still over 0.3 nmol/l. ATG was administered as an initial bolus of 9 mg/kg followed by 3 consecutive doses of 3 mg/kg. An interim analysis was performed to establish whether any significant changes in C-peptide production and insulin requirement had occurred that would justify the continuation of this pilot study. By May 2004, 11 subjects were assigned to treatment with ATG along with intensified insulin therapy and 6 to intensified insulin therapy with placebo, and were followed for a period of at least 6 months. During the first 12 months a significant difference in the insulin dose trends was found between the groups (p = 0.010) with a lower insulin dosage in the ATG group. There was also a difference in the glucagon stimulated C-peptide level trends of marginal significance (p = 0.068). Compared to values at screening, stimulated C-peptide levels significantly improved in the ATG group (p = 0.012) but not in the placebo group. Complete diabetes remission occurred in 2 patients in the ATG and in none of the placebo group. Glycosylated hemoglobin at 12 months tended to be lower in the ATG group (p = 0.088). Significant adverse effects of ATG treatment, mainly transient fever and moderate symptoms of serum sickness (7 and 6 subjects, respectively) were observed during the first month only. The interim analysis of this ongoing study suggests that short-term ATG therapy in type 1 diabetes of recent onset contributes to the preservation of residual C-peptide production and to lower insulin requirements in the first year following diagnosis.

Impairment of CD4(+)CD25(+) regulatory T-cells in autoimmune liver disease

BACKGROUND/AIMS

CD4(+) lymphocytes constitutively expressing the IL-2-receptor alpha-chain (CD25) regulate the activation of CD4 and CD8 autoreactive T-cells by suppressing their proliferation and effector function. The aim of this study is to: (1) measure the percentage of CD4(+)CD25(+) T-cells (T-regs) in patients with autoimmune liver disease at presentation and during remission, (2) correlate their frequency with disease activity, (3) determine their ability to expand and (4) to inhibit interferon-gamma (IFNgamma) production by CD4(+)CD25- T-cells.

METHODS

41 patients were studied. Percentage of T-regs was determined on peripheral blood mononuclear cells (PBMCs) by triple-colour flow cytometry; their ability to expand by exposing PBMCs to a T-cell expander (CD3/CD28 Dynabeads); their immunoregulatory function by measuring their ability to suppress IFNgamma production by CD4(+)CD25(-) T-cells.

RESULTS

T-regs were significantly less in patients than in controls, and at diagnosis than during remission. Their percentage was inversely correlated with titres of anti-liver kidney microsomal and soluble liver antigen autoantibodies. T-regs ability to expand was significantly lower in patients than in controls, but that to suppress IFNgamma production by CD4(+)CD25(-) T-cells was maintained.

CONCLUSIONS

Decreased T-regs numbers and ability to expand may favour the emergence of liver-targeted autoimmunity, despite preserved suppressor function. Treatment should aim at increasing T-regs number.