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Ezio Bonifacio

Publications and source records attributed to Ezio Bonifacio.

At least 19 recordsLinked to original sources
PubMed2026

International consensus guidance for general population screening for islet autoantibodies to diagnose early-stage type 1 diabetes: a nominal group technique process.

Type 1 diabetes is an autoimmune disease that targets and destroys insulin-producing beta cells in the pancreatic islets. The incidence of type 1 diabetes is rising globally. At the clinical diagnosis of type 1 diabetes, between 20% and 67% of children and adolescents present with diabetic ketoacidosis (DKA) requiring hospitalisation, and one-third of these require intensive care. Type 1 diabetes can be detected in early stages, prior to the insulin-requiring clinical diagnosis, through screening for islet autoantibodies (IAbs). Identifying individuals with early-stage type 1 diabetes, combined with monitoring of and education on disease progression, prevents DKA and results in a milder clinical onset. This allows for timely insulin initiation in outpatient settings and improved long-term glucose management. Early diagnosis also enables access to novel disease-modifying therapies that can delay the clinical onset of diabetes. In this international consensus, we provide guidance on the principles and practice of implementing general population screening for IAbs to diagnose early-stage type 1 diabetes. We also outline the minimum requirements for establishing effective population screening programmes to diagnose early-stage type 1 diabetes through IAb detection. This consensus statement has been endorsed by the following professional associations: Advanced Technologies & Treatments for Diabetes (ATTD); Association of Diabetes Care and Education Specialists (ADCES); Association Belge Du Diabète; Associazione Medici Diabetologi (AMD); Australian Diabetes Society (ADS); Belgian Diabetes Liga; Breakthrough T1D; Czech Diabetes Society (ČDS); EASD; Finnish Diabetes Association (FDS); Fondazione Italiana Diabete (FID); International Diabetes Federation (IDF)-Europe; International Society of Paediatric and Adolescent Diabetes (ISPAD); Paediatric Endocrinology Nursing Society (PENS); Polish Diabetes Society; Portuguese Diabetes Association (APDP); Sociedade Portuguesa de Diabetologia (SPD); Società Italiana di Diabetologia (SID); Société Francophone du Diabète (SFD) and Type 1 Diabetes Exchange (T1D Exchange).

Consensus report↗
PubMed2006

Combined testing of antibody titer and affinity improves insulin autoantibody measurement: Diabetes Antibody Standardization Program.

The aim of the workshop was to assess whether four laboratories could reproducibly measure insulin autoantibody (IAA) affinity in coded sera from non-diabetic relatives of patients with type 1 diabetes, newly diagnosed patients, and healthy blood donors, and whether combining affinity with autoantibody titer could improve concordance and performance of IAA assays. IAA affinity was measured by competitive binding using constant amounts of Tyr14A [125I] human insulin and increasing quantities of unlabeled human insulin. There was high concordance between laboratories in distinguishing high, moderate, and low affinity IAA, although IAA binding to insulin varied with assay format. Multiple islet autoantibody-positive and patient sera were identified by high affinity IAA regardless of laboratory-designated IAA status. Combining affinity and titer significantly improved sensitivity, specificity, and concordance of IAA measurement. This workshop has demonstrated that different laboratories are able to reproduce IAA affinity results and that considering IAA affinity is likely to improve the diagnostic performance of IAA assays.

Adolescent↗
PubMed2006

Monoclonal antibody 76F distinguishes IA-2 from IA-2beta and overlaps an autoantibody epitope.

IA-2 and IA-2beta are highly related proteins that are autoantigens in type 1 diabetes, and provide a model for developing reagents and assays that distinguish similar proteins with unique autoantibody epitopes. Monoclonal antibodies (mAb) to IA-2 and IA-2beta were prepared and tested for their ability to bind to the related proteins and their ability to compete for specific autoantibody epitope binding by sera from patients with type 1 diabetes. Monoclonal antibodies that specifically bound IA-2 (76F) or bound both IA-2 and IA-2beta (A9) were isolated and characterized. 76F mAb recognized IA-2 of human, rat and mouse origin in native and denatured forms and had an epitope specificity for residues 626-630 (FEYQD) which are found in the juxtamembrane (JM) region of human and mouse IA-2, but not IA-2beta. This region overlaps with the autoantibody epitope JM2. Binding to the 76F monoclonal antibody was specifically inhibited by sera with antibodies to the JM2 epitope but not with antibodies to the adjacent JM1 epitope, indicating that unique epitopes can be distinguished by this approach. 76F mAb has the unique property to distinguish between the two closely related autoantigens IA-2 and IA-2beta by targeting an IA-2 specific epitope of the juxtamembrane region. The findings define an approach to develop assays for specific antibody epitope measurements which may be relevant for disease prognosis and monitoring intervention therapies.

Amino Acid Sequence↗
PubMed2006

Induction of tolerance in type 1 diabetes via both CD4+CD25+ T regulatory cells and T regulatory type 1 cells.

Success in developing novel therapies to recommence self-tolerance in autoimmunity depends on the induction of T regulatory (Tr) cells. Here, we report that rapamycin combined with interleukin (IL)-10 efficiently blocks type 1 diabetes development and induces long-term immunotolerance in the absence of chronic immunosuppression in nonobese diabetic (NOD) mice. Rapamycin mediates accumulation in the pancreas of suppressive CD4(+)CD25(+)FoxP3(+) Tr cells, which prevent diabetes. IL-10 induces Tr type 1 (Tr1) cells, which reside in the spleen and prevent migration of diabetogenic T-cells to the draining lymph nodes. These two Tr cell subsets act in concert to control diabetogenic T-cells that are still present in long-term tolerant mice. Rapamycin plus IL-10 treatment, promoting distinct subsets of Tr cells, may constitute a novel and potent tolerance-inducing protocol for immune-mediated diseases.

Adoptive Transfer↗
PubMed2006

Predictors of postpartum diabetes in women with gestational diabetes mellitus.

The aim of this study was to stratify risk for postpartum diabetes in women who have gestational diabetes. Women with gestational diabetes were recruited between 1989 and 1999, and 302 were followed with oral glucose tolerance tests at 9 months and 2, 5, 8, and 11 years postpregnancy. The 8-year postpartum diabetes risk was 52.7% (130 diabetic cases). Risk was increased in women with autoantibodies to GAD and/or insulinoma antigen-2 (adjusted hazard ratio 4.1; P < 0.0001), women who required insulin during pregnancy (4.7; P < 0.0001), women with BMI >30 kg/m2 (1.5; P = 0.04), and women with more than two prior pregnancies (2.5; P = 0.02). Women without these risk factors had a postpartum diabetes risk of 14% by 8 years, and risk rose incrementally to 96% by 8 years in autoantibody-positive women. Parity status, C-reactive protein concentration, a diabetes family history, maternal age, weeks of gestation, and the child's birth weight did not significantly affect risk in multivariate analysis. Prospective diabetes assessment is indicated and intervention should be considered in women with gestational diabetes who are autoantibody positive, require insulin treatment during pregnancy, or are obese.

Adult↗
PubMed2006

Rapamycin and interleukin-10 treatment induces T regulatory type 1 cells that mediate antigen-specific transplantation tolerance.

Islet transplantation is a cure for type 1 diabetes, but its potential is limited by the need for constant immunosuppression. One solution to this problem is the induction of transplantation tolerance mediated by T regulatory cells. T regulatory type 1 (Tr1) cells are characterized by their production of high levels of interleukin (IL)-10, which is crucial for their differentiation and suppressive function. We investigated the effects of IL-10 administered in combination with rapamycin on the induction of Tr1 cells that could mediate a state of tolerance in diabetic mice after pancreatic islet transplantation. The efficacy of this treatment was compared with IL-10 alone and standard immunosuppression. Stable long-term tolerance that was not reversible by alloantigen rechallenge was achieved only in mice treated with rapamycin plus IL-10. Tr1 cells that produced high levels of IL-10 and suppressed T-cell proliferation were isolated from splenocytes of rapamycin plus IL-10-treated mice after treatment withdrawal. In rapamycin plus IL-10-treated mice, endogenous IL-10 mediated an active state of tolerance, as was observed when the blockade of IL-10 activity rapidly induced graft rejection >100 days after transplantation. CD4(+) T-cells from rapamycin plus IL-10-treated mice transferred antigen-specific tolerance in mice that received new transplants. Thus rapamycin plus IL-10 not only prevented allograft rejection but also induced Tr1 cells that mediated stable antigen-specific, long-term tolerance in vivo.

Adoptive Transfer↗
PubMed2005

Bone marrow mesenchymal stem cells express a restricted set of functionally active chemokine receptors capable of promoting migration to pancreatic islets.

Bone marrow-derived mesenchymal stem cells (BM-MSCs) are stromal cells with the ability to proliferate and differentiate into many tissues. Although they represent powerful tools for several therapeutic settings, mechanisms regulating their migration to peripheral tissues are still unknown. Here, we report chemokine receptor expression on human BM-MSCs and their role in mediating migration to tissues. A minority of BM-MSCs (2% to 25%) expressed a restricted set of chemokine receptors (CXC receptor 4 [CXCR4], CX3C receptor 1 [CX3CR1], CXCR6, CC chemokine receptor 1 [CCR1], CCR7) and, accordingly, showed appreciable chemotactic migration in response to the chemokines CXC ligand 12 (CXCL12), CX3CL1, CXCL16, CC chemokine ligand 3 (CCL3), and CCL19. Using human pancreatic islets as an in vitro model of peripheral tissue, we showed that islet supernatants released factors able to attract BM-MSCs in vitro, and this attraction was principally mediated by CX3CL1 and CXCL12. Moreover, cells with features of BM-MSCs were detected within the pancreatic islets of mice injected with green fluorescent protein (GFP)-positive BM. A population of bona fide MSCs that also expressed CXCR4, CXCR6, CCR1, and CCR7 could be isolated from normal adult human pancreas. This study defines the chemokine receptor repertoire of human BM-MSCs that determines their migratory activity. Modulation of homing capacity may be instrumental for harnessing the therapeutic potential of BM-MSCs.

Animals↗
PubMed2005

Predicting type 1 diabetes.

Predicting type 1 diabetes mellitus (T1DM) is a prerequisite for disease prevention. Prediction is currently performed on three levels, which include the genetic susceptibility for disease, the identification of preclinical T1DM by way of circulating islet autoantibodies, and the use of metabolic tests to stage preclinical disease into late or early prediabetes. Combinations of genetic markers such as HLA genotype, INS genotype, and if and how much family history of T1DM is present can stratify disease risk more than 1000-fold, and can be used for selection of first-degree relatives of patients with T1DM for primary intervention trials. Measurement of autoantibodies in genetically at-risk subjects identifies future cases of T1DM. Further stratification of diabetes risk in autoantibody-positive subjects can be made on the basis of autoantibody characteristics that correspond to the magnitude of the autoantibody response.

Autoantibodies↗
PubMed2005

C-reactive protein concentration is not related to islet autoimmunity status in offspring of parents with type 1 diabetes.

Autoimmunity may be associated with acute or chronic inflammation. In order to determine whether the inflammatory marker C-reactive protein (CRP) was an indicator of inflammatory events that precede, predict, or associate with islet autoimmunity or type 1 diabetes, CRP was measured in sequential antibody-negative, seroconversion, and follow-up-positive samples from 65 prospectively studied islet autoantibody-positive children. Although changes in CRP concentrations were observed in some children, overall CRP concentrations were similar in antibody-negative samples (median, 0.21 mg/L), antibody-positive samples (median, 0.26 mg/L), and samples at seroconversion (median, 0.26 mg/L). CRP concentrations at diabetes onset (median, 0.59 mg/L) were not significantly increased over antibody-negative samples (P = 0.07). CRP concentrations did not predict diabetes development. CRP concentrations were related to age (r = 0.26; P < 0.001) and were increased in samples obtained from October to January (P < 0.001). These findings suggest that CRP concentrations are not a valuable marker of progression to type 1 diabetes and highlight the importance of correcting analyses for seasonal variations.

Autoantibodies↗
PubMed2005

Humoral autoimmune responses to glutamic acid decarboxylase have similar target epitopes and subclass that show titer-dependent disease association.

Glutamic acid decarboxylase (GAD) is an autoantigen in stiff man syndrome (SMS) and type 1 diabetes (T1DM). Different GAD autoantibody characteristics in these disorders have suggested distinct underlying mechanisms of autoimmunity. Here, it is shown that increased prevalence of autoantibodies to GAD65 amino terminal and GAD67 epitopes and autoantibodies of IgG2, IgG3, or IgG4 subclass in patients with SMS (P < 0.001 vs. T1DM) are secondary to the markedly higher autoantibody titers in SMS patients (P < 0.0001) and that autoantibody epitopes and subclasses were similar when patients were matched for autoantibody titer. Exposure to autoantigen in the disorders is likely to involve similar humoral antigenic determinants, but different B cell regulation.

Antibody Formation↗
PubMed2005

Natural history of type 1 diabetes.

The natural history of autoimmune type 1 diabetes in children is associated with the appearance of islet autoantibodies early in life, which is influenced by genetic and environmental factors. Once islet autoantibodies have developed, the progression to diabetes in antibody-positive individuals is determined by the age of antibody appearance and by the magnitude of the autoimmunity, in turn related to the age of the subject. Characteristics that describe the magnitude of the autoimmunity can stage progression to type 1 diabetes in islet autoantibody-positive subjects regardless of genetic background or age.

Autoantibodies↗
PubMed2004

Brief communication: early appearance of islet autoantibodies predicts childhood type 1 diabetes in offspring of diabetic parents.

BACKGROUND: The development of type 1 diabetes mellitus is preceded by autoimmunity against islet beta cells. OBJECTIVE: To determine the risk for islet autoimmunity and childhood diabetes in offspring of affected parents. DESIGN: Prospective cohort study. SETTING: German BABYDIAB study. PARTICIPANTS: 1610 offspring of parents with type 1 diabetes. MEASUREMENTS: Autoantibodies to islet autoantigens were measured at 9 months, 2 years, 5 years, and 8 years of age. RESULTS: By 5 years of age, the frequency of islet autoantibodies was 5.9% (95% CI, 4.6% to 7.2%), the frequency of multiple islet autoantibodies was 3.5% (CI, 2.5% to 4.5%), and the frequency of diabetes was 1.5% (CI, 0.9% to 2.1%). The risk for diabetes was highest in offspring with multiple autoantibodies (40% within 5 years vs. 3% in offspring with single autoantibodies; P = 0.005). Progression to multiple islet autoantibodies was fastest in children who were autoantibody positive by age 2 years (P < 0.001), and progression to diabetes was inversely related to the age of positivity for multiple autoantibodies (P = 0.02). LIMITATIONS: The findings are limited to childhood diabetes in affected families. CONCLUSIONS: Childhood autoimmune diabetes is associated with autoimmunity that starts before 2 years of age.

Autoantibodies↗
PubMed2004

Up-regulation of CD1d expression restores the immunoregulatory function of NKT cells and prevents autoimmune diabetes in nonobese diabetic mice.

The immunoregulatory function of NKT cells is crucial for prevention of autoimmunity. The prototypical NKT cell Ag alpha-galactosylceramide is not present in mammalian cells, and little is known about the mechanism responsible for NKT cell recruitment and activation. Up-regulation of CD1d, the NKT cell restriction molecule, expressed on mononuclear cells infiltrating the target organ, could represent the physiological trigger for NKT cells to self-contain T cell immunity and to prevent autoimmune disease. Recognition of CD1d, either by itself or bound to self-ligands (selfCD1d), could drive NKT cells toward an immunoregulatory phenotype. Hence, ineffective NKT cell-mediated immunoregulation in autoimmune-prone individuals including nonobese diabetic (NOD) mice could be related to defective signals that regulate CD1d expression at time and site of autoimmunity. To test this hypothesis, we transgenically overexpressed CD1d molecules under the control of the insulin promoter within the pancreatic islets of NOD mice (insCD1d). Recognition of overexpressed CD1d molecules rescued NKT cell immunoregulatory function and prevented autoimmune diabetes in insCD1d transgenic NOD mice. Protection from diabetes was associated with a biased IL-4-secreting cytokine phenotype of NKT cells and alteration of the cytokine microenvironment in the pancreatic lymph nodes of transgenic mice. The net effect was a reduced development of the autoimmune T cell repertoire. Our findings suggest that up-regulation of CD1d expression during inflammation is critical to maintain T cell homeostasis and to prevent autoimmunity.

Animals↗
PubMed2004

Delayed exposure to wheat and barley proteins reduces diabetes incidence in non-obese diabetic mice.

Dietary gluten, vitamin D3, and fish-oil are suggested to influence the incidence of autoimmune diabetes. To determine whether modification of their intake could reduce diabetes incidence and autoimmunity in mice, pups from female non-obese diabetic (NOD) mice were fed diets modified for protein source, fatty acid content, and/or vitamin D3 content and were followed for diabetes development, insulin autoantibodies (IAA), and insulitis. Replacement of wheat and barley with poultry as the major protein source significantly affected diabetes development. Diabetes onset was delayed and diabetes incidence was significantly reduced in female mice that received the wheat and barley protein-free diet throughout life (45% by age 32 weeks vs. 88% in control mice; P < 0.01), from weaning (42%; P < 0.005), or from 3 to 10 weeks of age only (36%; P < 0.01), and diabetes development was not completely restored by gliadin supplementation of the wheat and barley protein-free diet (58%; P < 0.05). Insulin autoantibodies (P < 0.01) and insulitis scores (P < 0.02) were reduced, and intra-pancreatic IL-4 mRNA increased (P < 0.05) in wheat and barley protein-deprived mice. Diabetes incidence was neither reduced by fish-oil or vitamin D3 supplementation alone, nor in mice fed a wheat and barley protein-free diet that was supplemented with fish-oil and vitamin D3. These data support a link between dietary wheat and barley proteins and the development of autoimmune diabetes.

Animals↗
PubMed2004

Mature high-affinity immune responses to (pro)insulin anticipate the autoimmune cascade that leads to type 1 diabetes.

Children at risk for type 1 diabetes can develop early insulin autoantibodies (IAAs). Many, but not all, of these children subsequently develop multiple islet autoantibodies and diabetes. To determine whether disease progression is reflected by autoantibody maturity, IAA affinity was measured by competitive radiobinding assay in first and subsequent IAA-positive samples from children followed from birth in the BABYDIAB cohort. IAA affinity in first positive samples ranged from less than 10(6) l/mol to more than 10(11) l/mol. High affinity was associated with HLA DRB1*04, young age of IAA appearance, and subsequent progression to multiple islet autoantibodies or type 1 diabetes. IAA affinity in multiple antibody-positive children was on average 100-fold higher than in children who remained single IAA positive or became autoantibody negative. All high-affinity IAAs required conservation of human insulin A chain residues 8-13 and were reactive with proinsulin. In contrast, most lower-affinity IAAs were dependent on COOH-terminal B chain residues and did not bind proinsulin. These data are consistent with the concept that type 1 diabetes is associated with sustained early exposure to (pro)insulin in the context of HLA DR4 and show that high-affinity proinsulin-reactive IAAs identify children with the highest diabetes risk.

Amino Acid Sequence↗
PubMed2004

Tissue factor and CCL2/monocyte chemoattractant protein-1 released by human islets affect islet engraftment in type 1 diabetic recipients.

Islet survival in the early posttransplantation period is likely to be influenced by inflammatory events in and around islets. Twenty-seven human islet preparations were transplanted by 24 infusions into 14 patients with brittle type 1 diabetes under the Edmonton protocol. Patients were monitored for their coagulation [cross-linked fibrin degradation products (XDPs)] and liver function test [aspartate and alanine aminotransferase (AST and ALT)] as markers of early posttransplant complications, and these were correlated with in vitro islet number, purification, volume, monocyte-chemoattractant protein-1 (CCL2/MCP-1) and tissue factor (TF) islet release. Consistent with activation of coagulation pathways and hepatic damage, serum XDP values increased early after 11 infusions and transaminase after 13 of 24 infusions. TF and CCL2/MCP-1 were detected in supernatants of 21 and 22 islet preparations, respectively. Serum XDP peak values were correlated with TF/equivalent islets (EI) (r(2)=0.26, P = 0.001) and CCL2/MCP-1/EI (r(2) = 0.42; P < 0.001); serum transaminase areas under the curve in the first week posttransplantation were correlated with CCL2/MCP-1/EI (r(2) = 0.55; P < 0.001 for ALT and r(2) = 0.51; P = 0.001 for AST) and TF/EI (r(2) = 0.31; P = 0.002 for ALT, and r(2) = 0.36; P = 0.002 for AST). These data suggest that reducing the islet proinflammatory state may be a means to reduce the early posttransplant complications and perhaps improve islet engraftment.

Chemokine CCL2↗