Antibodies to GAD65 epitopes at diagnosis and over the first 10 years of clinical type 1 diabetes mellitus.

Antibodies to glutamate decarboxylase (GAD65Ab) may persist, and their titres even increase after the clinical onset of type 1 diabetes. To characterize this phenomenon in detail, we analysed sequentially antibodies to GAD65 epitope clusters in a radio-binding assay in patients with type 1 diabetes. Serum samples were taken at diagnosis and 2, 5 and 10 years later from 50 young patients who had tested positive for GAD65Ab at least once during observation.

Natural course of preclinical type 1 diabetes in siblings of affected children.

Aim: To define the dynamics of preclinical type 1 diabetes in siblings of affected children and to characterize the siblings experiencing a progressive process.

Methods: From 801 families taking part in the "Childhood Diabetes in Finland" (DiMe) Study, 715 initially unaffected siblings were graded into four stages of preclinical type 1 diabetes based on the initial number of disease-associated autoantibodies detectable close to the time of diagnosis of the index case, while another classification system covering 641 of the siblings was based on a combination of the initial number of antibodies and the first-phase insulin response (FPIR) to intravenous glucose.

Results: Based on the first classification, there was a total of 95 siblings with initial signs of prediabetes, out of whom 34 (36%) progressed, 26 (27%) remained stable and 35 (37%) regressed during prospective observation for a median of 3.

Genetic modification of risk assessment based on staging of preclinical type 1 diabetes in siblings of affected children.

We set out to study the association between human leukocyte antigen-defined genetic disease susceptibility and the stage of preclinical type 1 diabetes and whether genetic predisposition affects the natural course of preclinical diabetes in initially nondiabetic siblings of affected children. A total of 701 initially unaffected siblings were graded into four stages of preclinical type 1 diabetes based on the initial number of disease-associated autoantibodies detectable close to the time of diagnosis of the index case: no prediabetes (no antibodies), early (one antibody specificity), advanced (two antibodies), and late prediabetes (three or more antibodies). Another classification system covering 659 siblings was based on a combination of the initial number of antibodies and the first-phase insulin response (FPIR) to iv glucose: no prediabetes (no antibodies), early (one antibody specificity, normal FPIR), advanced (two or more antibodies, normal FPIR), and late prediabetes (at least one antibody, reduced FPIR).

Time-resolved fluorometric assay for detection of autoantibodies to glutamic acid decarboxylase (GAD65).

Background: Type 1 diabetes mellitus results from destruction of the pancreatic insulin-producing beta cells by a chronic autoimmune process. Methods are needed for the detection of circulating autoantibodies to glutamic acid decarboxylase (GAD65), a major marker of this process.

Methods: Streptavidin-coated microtiter plates were incubated with biotinylated GAD65, and after incubation with serum samples from patients with type 1 diabetes mellitus and control individuals, europium-labeled GAD65 was added.

Soluble adhesion molecules in pre-clinical Type 1 diabetes: a prospective study.

Aims: This prospective case-control study aimed at evaluating the time course of serum concentrations of soluble adhesion molecules; intercellular adhesion molecule-1 and L-selectin in siblings with signs of pre-clinical Type 1 diabetes in order to relate these concentrations to autoantibody status and to assess whether these markers could discriminate between those siblings who progressed to clinical diabetes and those who remained non-diabetic.

Methods: Serum levels of soluble adhesion molecules were measured with enzyme-linked immunosorbent assays in autoantibody-positive initially healthy siblings of diabetic children who progressed to clinical disease during the observation period of 10 years and in sex- and age-matched autoantibody-positive siblings who have remained unaffected.

Results: The intraindividual and interindividual variability in the concentrations of soluble adhesion molecules was conspicuous both among the progressors and non-progressors.

Signs of beta-cell autoimmunity and HLA-defined diabetes susceptibility in the Finnish population: the sib cohort from the Type 1 Diabetes Prediction and Prevention Study.

Aims/hypothesis: To assess the role of HLA-defined genetic diabetes susceptibility in the appearance of signs of beta-cell autoimmunity in a series of children derived from the general population.

Methods: Tests for five HLA DQB1 alleles and four diabetes-associated autoantibodies were carried out on 1,584 older sibs of infants with an increased HLA-defined genetic risk of Type 1 diabetes. The DQB1 genotypes were classified into those conferring high (* 02/0302), moderate (* 0302/x; where x indicates * 0302 or a non-defined allele), low (* 0301/0302, * 02/0301, * 02/x, * 0302/0602, * 0302/0603; where x indicates * 02 or a non-defined allele) or decreased risk (other genotypes).

Natural history of beta-cell autoimmunity in young children with increased genetic susceptibility to type 1 diabetes recruited from the general population.

The aim of this study was to evaluate the frequency and predictive value of diabetes-associated autoantibodies, such as islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD65 (GADA), and the IA-2 molecule (IA-2A) in genetically susceptible children from the general population during the first 2 yr of life. Of 12,170 newborn infants, 1,005 with increased genetic risk of type 1 diabetes (high risk, human leukocyte antigen DQB1*02/*0302; moderate risk, DQB1*0302/x, where x = other than *02, *0301, or *0602) were monitored for ICA, IAA, GADA, and IA-2A at 3- to 6-month intervals from birth up to a minimum age of 2 yr. In addition, all 15 genetically susceptible children from the general population who had participated in regular immunological follow-up and developed clinical type 1 diabetes by the end of April 2000 were analyzed for the development of autoantibodies.

Prevalence and fate of type 1 diabetes-associated autoantibodies in cord blood samples from newborn infants of non-diabetic mothers.

Background: Cord blood samples were collected from 1002 consecutive births at Turku University Hospital to study the prevalence and fate of type 1 diabetes-associated autoantibodies in newborn infants of unaffected mothers.

Methods: The samples were analysed for cytoplasmic islet cell antibodies (ICA), autoantibodies to the 65 kD isoform of glutamic acid decarboxylase (GADA), autoantibodies to the protein tyrosine phosphatase related IA-2 antigen (IA-2A), insulin autoantibodies (IAA) and HLA DQB1 genotypes.

Results: ICA were detected in 27 cord blood samples (2.

Autoantibodies to GAD, IA-2 and insulin in ICA-positive first-degree relatives of children with type 1 diabetes: a comparison between parents and siblings.

Background: Islet cell antibodies (ICA) represent a heterogenous group of autoantibodies to diabetes-associated antigens, including glutamic acid decarboxylase (GAD) and the IA-2 protein. The objectives of the present study were to compare the prevalence of autoantibodies to known biochemically characterized autoantigens between ICA-positive non-diabetic parents and siblings of children with type 1 diabetes and to evaluate how such antibodies explain ICA reactivity.

Methods: The presence and levels of GAD antibodies (GADA), IA-2 antibodies (IA-2A) and insulin autoantibodies (IAA) were analyzed in the sera of 184 ICA-positive first-degree relatives (79 parents and 105 siblings).

Disease-associated autoantibodies during pregnancy and at birth in families affected by type 1 diabetes.

We studied the pattern of type 1 diabetes-associated autoantibodies during pregnancy and the transplacental transfer of these autoantibodies to the fetal circulation and searched for possible signs of prenatal induction of beta-cell autoimmunity in newborn infants. The population comprised 208 mothers and their newborn infants. Seventy-four of the mothers (36%) had type 1 diabetes and 134 (64%) of the infants had an affected father or sibling.

Dynamic pattern of disease-associated autoantibodies in siblings of children with type 1 diabetes: a population-based study.

To study the dynamics of disease-associated humoral immune responses, we analyzed autoantibodies to the IA-2 protein (IA-2A), glutamic acid decarboxylase (GADA), and insulin (IAA) and also islet cell antibodies (ICA) in a population-based, prospective, representative series of 710 siblings (<20 years of age) of children with type 1 diabetes. Positivity for single autoantibodies was observed in 8-13% of these siblings during an average follow-up of 4 years. The overall incidence rates per 1,000 years (number of cases/person-years in parentheses) for positive seroconversion of IA-2A were nine (19/2,123), followed by six (12/2,049) for GADA, 19 (40/2,111) for IAA, and 16 (31/1965) for ICA.

The first signs of beta-cell autoimmunity appear in infancy in genetically susceptible children from the general population: the Finnish Type 1 Diabetes Prediction and Prevention Study.

Little is known about the timing of the etiological events and the preclinical process of type 1 diabetes during the first years of life in the general population. In this population-based prospective birth cohort study, the appearance of diabetes-associated autoantibodies as a sign of beta-cell autoimmunity and the development of type 1 diabetes were monitored from birth. Of 25,983 newborn infants, 2,448 genetically susceptible children were monitored for islet cell antibodies (ICA) at 3- to 6-month intervals.

Enterovirus antibody levels during the first two years of life in prediabetic autoantibody-positive children.

Aims/hypothesis: We evaluated the role of enterovirus infections in the pathogenesis of Type I (insulin-dependent) diabetes mellitus by monitoring enterovirus antibody levels in prediabetic children who turned positive for diabetes-associated autoantibodies in a prospective birth cohort study.

Methods: Serial serum samples taken during prospective observation starting at birth were analysed for IgG and IgA class antibodies against enterovirus antigens including purified coxsackievirus B4, echovirus 11, poliovirus 1 and a synthetic enterovirus peptide antigen using enzyme immunoassay. Maternal samples taken at the end of the third month of pregnancy were also studied.

Fecal leukocyte stain has diagnostic value for outpatients but not inpatients.

The methylene blue stain for fecal leukocytes (FL) is widely used as an adjunct to slower but more accurate tests of diarrheal etiology, such as stool culture (SCx) or toxin assays for Clostridium difficile. Prior studies investigating the utility of FL for predicting SCx and C. difficile toxin assay (CDTA) results did not evaluate the importance of inpatient versus outpatient status.

Soluble adhesion molecules in preclinical type 1 diabetes. The Childhood Diabetes in Finland Study Group.

We measured the concentrations of the soluble forms of the intercellular adhesion molecule-1 (sICAM-1) and L-selectin in 95 autoantibody-positive siblings of children with type 1 diabetes and 95 sex- and age-matched siblings testing negative for diabetes-associated autoantibodies to assess the possible role of soluble adhesion molecules as markers of progressive ss-cell destruction in preclinical diabetes and their ability to discriminate between those siblings who progress to clinical disease and those who remain nondiabetic. We observed an inverse correlation between age and the levels of both sICAM-1 (r = -0.31, p < 0.

Genetic, autoimmune, and clinical characteristics of childhood- and adult-onset type 1 diabetes.

Objective: To assess whether there are any differences in genetic, autoimmune, or clinical features between type 1 diabetes presenting in childhood and that diagnosed later.

Research Design And Methods: We studied 352 individuals (252 children and adolescents <20 years of age and 100 adults > or =20 years of age) manifesting clinical signs of type 1 diabetes over a period of 7.5 years at a university hospital in northern Finland with a primary catchment area population of approximately 300,000.

Enterovirus infection as a risk factor for beta-cell autoimmunity in a prospectively observed birth cohort: the Finnish Diabetes Prediction and Prevention Study.

Previous studies suggest that enterovirus infections may initiate and accelerate beta-cell damage years before the clinical manifestation of type 1 diabetes. We have now analyzed the role of enterovirus infections in the initiation of autoimmunity in children who have tested positive for diabetes-associated autoantibodies in a prospective study starting at birth (the Finnish Diabetes Prediction and Prevention Study). The frequency of enterovirus infections was studied using both serology and testing for the presence of enterovirus RNA in the sera of 21 children who developed and retained autoantibodies and in 104 control subjects chosen from the same study cohort and matched for the time of birth, sex, and HLA alleles determining genetic diabetes susceptibility.

Autoantibodies to glutamic acid decarboxylase in patients with therapy-resistant epilepsy.

Background: Autoantibodies to glutamic acid decarboxylase (GAD-A) are present in type 1 diabetes and stiff man syndrome (SMS), and have also been reported in cerebellar ataxia. Epilepsy was present in 4 of 19 patients with SMS and GAD-A, implying that epilepsy sometimes is associated with anti-GAD autoimmunity.

Methods: The authors investigated the prevalence of GAD-A in patients with therapy-resistant localization-related epilepsy (n = 51) and generalized epilepsy (n = 49) by a radiobinding assay.

Stability of autoantibodies and their relation to genetic and metabolic markers of Type I diabetes in initially unaffected schoolchildren.

Aims/hypothesis: To study temporal changes in positivity for autoantibodies associated with Type I (insulin-dependent) diabetes mellitus and the relations between these antibodies, HLA-DQB1-risk markers and first-phase insulin response (FPIR) in non-diabetic schoolchildren.

Methods: The stability of the antibody status over 2 years was assessed in 104 schoolchildren initially positive for islet cell antibodies (ICA) or antibodies to the 65,000 M(r) isoform of the glutamic acid decarboxylase (GADA) or both and in 104 antibody-negative control children matched for sex, age and place of residence. All children were also studied for their first-phase insulin response and HLA-DQB1 alleles on the second occasion.

Enterovirus RNA in serum is a risk factor for beta-cell autoimmunity and clinical type 1 diabetes: a prospective study. Childhood Diabetes in Finland (DiMe) Study Group.

Recent prospective studies have documented serologically an increased frequency of enterovirus infections in prediabetic children, indicating that these infections may initiate and accelerate the beta-cell damaging process several years before the clinical manifestation of type 1 diabetes. The aim of the present study was to establish whether these serological findings would be supported by the detection of enterovirus RNA in a unique prospective series of sera collected from prediabetic children 0-10 years before the manifestation of clinical type 1 diabetes. Reverse transcription followed by polymerase chain reaction employing highly conserved primers among enteroviruses were used to amplify enteroviral sequences.

Disease-associated autoantibodies as surrogate markers of type 1 diabetes in young children at increased genetic risk. Childhood Diabetes in Finland Study Group.

To evaluate the emergence of diabetes-associated autoantibodies in young children and to assess whether such antibodies can be used as surrogate markers of type 1 diabetes in young subjects at increased genetic risk, we studied 180 initially unaffected siblings (92 boys and 88 girls) of children with newly diagnosed type 1 diabetes. All siblings were younger than 6 yr of age at the initial sampling, and they were monitored for the emergence of islet cell antibodies (ICA), insulin autoantibodies (IAA), glutamate decarboxylase antibodies (GADA), and IA-2 antibodies (IA-2A) up to the age of 6 yr and for progression to clinical type 1 diabetes up to the age of 10 yr. All 160 siblings with DNA samples available were typed for susceptible (DQB1*02 and *0302) and protective (DQB1*0301 and *0602-03) HLA DQB1 alleles.

Genetic markers, humoral autoimmunity, and prediction of type 1 diabetes in siblings of affected children. Childhood Diabetes in Finland Study Group.

The relationships between genetic markers and disease-associated autoantibodies were studied in an unselected population of 701 siblings of children with type 1 diabetes, and the predictive characteristics of these markers over a period of 9 years were determined. Increased prevalences of all the antibodies were closely associated with HLA identity to the index case, the DR4 and DQB1*0302 alleles, and the DR3/4 phenotype and the DQB1*02/0302 genotype. Antibodies to GAD (GADA) were also associated with the DR3 and DQB1*02 alleles.

Absence of glutamic acid decarboxylase antibodies in childhood epilepsies.

Glutamic acid decarboxylase antibodies are present in some patients with therapy-resistant epilepsy. The authors measured glutamic acid decarboxylase antibodies in an unselected population of 114 children with different types of epilepsy. Three children with temporal lobe epilepsy and six children with various other types of epilepsy had intractable epilepsy.

Relation between T-cell responses to glutamate decarboxylase and coxsackievirus B4 in patients with insulin-dependent diabetes mellitus.

Background: the role of enteroviruses has been implicated in the etiology of insulin-dependent diabetes mellitus (IDDM). A possible connection between glutamate decarboxylase (GAD) autoimmunity and enterovirus infections in IDDM has been suggested to be based on a homology region between GAD and the non-structural protein 2C of coxsackievirus B4 (CVB4).

Objectives: the aims of the study were to measure the occurrence of cellular immunity to GAD and CVB4 in Finnish patients with newly diagnosed IDDM, and to study the relation between these two responses.