Levels Of Islet Cell Antibodies Research Articles

Monitoring of Autoantibodies Following Autologous Hematopoietic Stem Cell Transplantation in 6 Children with Recently Diagnosed Type 1 Diabetes Mellitus.

BACKGROUND Bone marrow stem cells have been shown to be a promising therapeutic strategy for autoimmune diseases. This study aimed to assess the safety and efficacy of autologous hematopoietic stem cell (ABMSC) transplantation without immunoablation used to suppress the autoimmune reaction in 6 children with newly diagnosed autoimmune diabetes mellitus. We monitored the levels of islet cell antibodies (ICA), antibodies against islet antigen-related tyrosine phosphatase 2 (IA2), glutamic acid-decarboxylase (GAD) antibodies, and anti-insulin antibodies (AIA). MATERIAL AND METHODS Between 2018 and 2022, 6 children (age 6-10 years, average 8 years) recently diagnosed with type 1 diabetes mellitus with the presence of ICA, IA2, GAD, AIA and ketoacidosis, were treated with an ABMSC stimulated with Filgrastim, granulocyte colony-stimulating factor (G-CSF), 10 ug/kg/day for 4 days. Bone marrow was harvested on day 5, collected by puncture and identified as mononuclear cells >180×10⁶/kg, CD34+ >0.22%, and transplanted by intravenous (i.v.) infusion. Patients were monitored with ICA, IA2, GAD, AIA, C-peptide, blood glucose, and glycosylated hemoglobin A1c (HbA1C) 6 months after the procedure. RESULTS At 6-month follow-up, we observed a negative value of the ICA, which was previously positive (P<0.001). The IA2 (p=0.037) and GAD (P=0.377) antibodies decreased slowly but were significantly lower. AIA remained high. A decrease in blood glucose and HbA1C levels was observed (P<0.001). No complications occurred during follow-up. CONCLUSIONS Autologous hematopoietic stem cell transplantation without immunoablation was safe and effective in significantly decreasing the production and effect of autoantibodies against ICA, GAD, and IA2, as well as decreasing blood sugar levels and HbA1c.

Role of C-Peptide in Relation to Levels of Anti-GAD and Islet Cell Antibodies in Characterizing Types of Diabetes in the Young, in Eastern India

Background: Measuring fasting C-peptide (FCP) and antibodies against Glutamic acid decarboxylase (GADA) and Islet cell antibodies (ICA) are not so commonly explored in children and young adults. Objectives: To assess the levels of FCP, GADA and ICA in subjects below the age of 25 years with DM and compare their levels to differentiate between Autoimmune and Non-Autoimmune Type 1 DM. Methodology: Blood samples of 93 subjects diagnosed with DM, reporting to the tertiary care hospital, were analysed for ICA, GADA and FCP. Receiver operating characteristics (ROC) curves were analysed to check the ability of autoimmune markers, BMI and C-peptide to differentiate between Autoimmune (Ai) and Non-Autoimmune (NonAi) diabetes. Results: 30/93 (32.2%) were positive for anti-GAD ab and/or ICA and categorised as Autoimmune (Ai), the most common antibody being, anti-GAD ab (80%) in them. The level of FCP among Ai compared to NonAi, was significantly low (p 20.75 nmol/l) as a very dependable test for diagnosing Ai, Type 1 DM, in children and young adults. Its sensitivity and specificity are in the range of 86.2% and 96.8% respectively. Low level of C-peptide (<0.36 nmol/l) is a fair indicator for diagnosing Ai diabetes in the same population unlike BMI. Conclusion: This study revealed predominant positivity for anti-GAD ab (80%) among Ai+ patients. ROC analysis shows GADA above 20.75 nmol/l and Fasting C-peptide < 0.36 nmol/l as a good indicator for diagnosing Ai in children and young adults.

Islet cell antibodies (ICA) identify autoimmunity in children with new onset diabetes mellitus negative for other islet cell antibodies

The aim of this study was to explore whether islet cell antibodies (ICA) could be identified in children with newly onset diabetes mellitus but negative for autoantibodies against glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A), insulin (IAA), or any of the three variants with arginine (R), tryptophan (W), or glutamine (Q) at position 325 of the zinc transporter 8 (ZnT8A). A population-based analysis of autoantibodies was performed from 1 May 2005 to 2 September 2010 in Swedish children newly diagnosed with diabetes. ICA was analyzed with an enzyme-linked immunosorbent assay and if positive, reanalyzed in the classical ICA immunofluorescence assay, in 341 samples among 3545 children who had been tested negative for all of GADA, IA-2A, IAA, or ZnT8A (R, W, Q). An isolated positivity for ICA was identified in 5.0% (17/341) of the newly diagnosed children. The levels of ICA in positive subjects ranged from 3 to 183 JDF-U (median 30). This finding increased the diagnostic sensitivity of islet autoimmunity as 3204/3545 patients (90.4%) were islet autoantibody positive without the ICA analyses and 3221 patients (90.9%) were positive with the inclusion of ICA. The finding of an isolated positivity for ICA despite negativity for GADA, IA-2A, IAA, and ZnT8A (R, W, Q) suggests that still another yet unidentified autoantigen(s) may contribute to the ICA immunofluorescence. Hence, ICA is important to analyze in type 1 diabetes children and adolescents that would otherwise be islet autoantibody negative.

Extended family history of autoimmune diseases and phenotype and genotype of children with newly diagnosed type 1 diabetes

Based on the concept of clustering autoimmunity, children with a positive family history of autoimmunity could be expected to have a different pathogenetic form of type 1 diabetes (T1D) and thus a stronger autoimmune reactivity against β-cells and an increased prevalence of the HLA-DR3-DQ2 haplotype. We tested this hypothesis in a cross-sectional observational study from the Finnish Pediatric Diabetes Register. HLA class II genotypes and β-cell autoantibodies were analyzed, and data on the extended family history of autoimmunity and clinical markers at diagnosis were collected with a structured questionnaire from 1488 children diagnosed with T1D under the age of 15 years (57% males). Only 23 children (1.5%) had another autoimmune disease (AID) known at diagnosis, and they had a milder metabolic decompensation at diabetes presentation. One-third (31.4%) had at least one relative with an AID other than T1D with affected mothers being overrepresented (8.2%) compared with fathers (2.8%). The children with a positive family history of other AIDs had higher levels of islet cell antibodies (P=0.003), and the HLA-DR3-DQ2 haplotype in the children was associated with celiac disease in the extended family (P<0.001), but not with an increased frequency of autoimmune disorders, in general. Approximately one-third of children with newly diagnosed T1D have a first- and/or second-degree relative affected by an AID. Our data do not consistently support the hypothesis of differential pathogenetic mechanisms in such children.

Islet cell autoantibodies in patients younger than 20 years of age with recently diagnosed diabetes in Northwest of Iran

The presence or absence of islet cell autoantibodies is one of the most direct ways to distinguish between type 1 and 2 diabetic patients. The objective of the present study was to assess the prevalence of β-cell autoantibodies such as glutamic acid decarboxylase-65 antibodies (GADAs) and islet cell antibodies (ICA) among patients younger than 20 years of age with recently diagnosed diabetes in northwest of Iran. From 2006 to 2008, 163 patients were enrolled in this study. They were clinically classified into two groups: 136 with type 1 diabetes (T1D) and 27 with type 2 diabetes (T2D). Serum levels of GADAs, ICA and C-peptide were determined with enzyme linked immunosorbent assay (ELISA) kits. Fasting blood glucose and HbA1c levels were also determined. Chi-square test, independent t test and one-way analysis of variance were used for data analysis. The prevalence of GADAs in T1D patients was 33.1%, slightly lower than that of ICA 35.3%. Forty-eight patients (35.3%) with T1D were positive for ICA compared to only one (3.7%) in T2D patients. The overall occurrence of any autoantibody in T1D patients (60.3%) was significantly higher than that of T2D patients (18.5%) (P < 0.001). There was a statistically different association with family history of diabetes among the autoantibody positive versus autoantibody negative patients with T1D (P < 0.01). Our results confirmed the presence of GADAs and ICA in T1D patients in Iran, though roughly at a lower prevalence than that reported for Caucasian T1D patients, but very similar to other non-Caucasian ethnic populations.

Progression to type 1 diabetes in islet cell antibody-positive relatives in the European Nicotinamide Diabetes Intervention Trial: the role of additional immune, genetic and metabolic markers of risk

To examine the role of additional immune, genetic and metabolic risk markers in determining risk of diabetes in islet cell antibody (ICA)-positive individuals with a family history of type 1 diabetes recruited into the European Nicotinamide Diabetes Intervention Trial. Five hundred and forty-nine first-degree relatives with confirmed ICA levels > or =20 Juvenile Diabetes Foundation units (mean age 15.9 years; interquartile range 10.4-33.7 years) were recruited from 20 countries. OGTTs and IVGTTs were performed at baseline, antibodies to glutamate decarboxylase (GADA), protein tyrosine phosphatase (IA-2A) and insulin (IAA) were determined by RIA, and HLA class II genotyping was performed by PCR of sequence-specific oligonucleotides. One hundred and fifty-nine participants developed diabetes within 5 years. Univariate analysis showed that the cumulative risk of development of diabetes within 5 years varied according to age, relationship to the proband, positivity for IAA, IA-2A and GADA, number and combination of islet antibodies, HLA class II genotype, baseline glucose tolerance, and first-phase insulin secretion, but not gender or incidence of childhood type 1 diabetes in the background population. Children aged < or =10 years had a 59% risk of diabetes within 5 years, compared with 11% in those > or =25 years (p<0.0001). Using multivariate analysis, independent determinants were age, first-phase insulin response, baseline glucose tolerance and number of additional antibody markers, but not antibody type or genotype. Individuals <25 years with two or more additional antibodies at baseline had a 62% risk of diabetes within 5 years and these combined criteria identified 81% of the cases in the whole cohort. We suggest that screening and recruitment for future intervention trials should be limited to family members aged <25 years, and should be based on islet autoantibodies alone.

Human Fetal Islet Transplantation in Type 1 Diabetics: Comparison of Immunological Effects Between Multiple Implantation Regimens

Previous studies have suggested that the multiple transplants might be equally metabolically efficient to a single regimen for human adult islets. The aim of this study was to compare immunological and metabolic parameters after each of the two regimens of human fetal islets (HFI). Group A single transplants (n = 9) had 180 ± 20 × 1000 HFI equivalents (IEQs) implanted via a single intramuscular injection. In group B multiple transplants (n = 8) islets were implanted by three consecutive injections of 60 ± 10 × 1000 IEQs at 7-day intervals. We analyzed the immunological parameters of CD 4/CD 8 T lymphocyte ratios; islet cell antibodies (ICAs) and insulin antibodies (IAs). We estimated insulin secreting capacity (ISC) as the metabolic parameter. We observed that the CD 4 +/CD 8 + T-cell ratio increased, peaking on day 90, in similar fashion in both groups: day −1: A = 1.18 ± 0.03 versus B = 1.19 ± 0.04; on day 90: A = 1.79 ± 0.09, versus B = 1.75 ± 0.08 ( P = NS) immediately before the decrease in C-peptide levels. Thereafter the ratios rapidly decreased without statistical differences. The levels of ICAs did not change. The levels of IAs, which were increased before transplant, then decreased without statistical differences between the groups. The values of ISC increased after transplant and then decreased similar to the T-cell ratio. Our results demonstrated that regimens of multiple and single HFIs did not show differences in the kinetics of the immunological response presumably mediating graft destruction. The CD 4/CD 8 ratio increased as the C-peptide level decreased, peaking on day 90 at the time of a decrease in C-peptide. These results may be useful for clinical studies of HFIs for type 1 diabetic patients.

Increased Frequency of Islet Cell Antibodies in Unaffected Brothers of Children with Type 1 Diabetes

Aim: To assess the relation between islet cell antibody (ICA) positivity and demographic characteristics in an extensive series of first-degree relatives of children with type 1 diabetes (T1D). Methods: Family members of children diagnosed with T1D before the age of 16 years and attending one of 27 participating paediatric units in Finland taking care of children with diabetes were invited to volunteer for an ICA screening program aimed at identifying individuals eligible for inclusion in the European Nicotinamide Diabetes Intervention Trial (ENDIT). The final series comprised 2,522 first-degree relatives (1,107 males) with a mean age of 20.4 (range 0.1–51.9) years, out of whom 390 were fathers, 622 mothers, 717 brothers, and 793 sisters of affected cases. Results: Two hundred and four family members (8.1%) tested positive for ICA with levels ranging from 3 to 564 (median 18) Juvenile Diabetes Foundation (JDF) units. One hundred and five relatives (4.2%) had an ICA level of 18 JDF units or more. Males had detectable ICA more often than females (9.6 vs. 6.9%; p = 0.02). Antibody-positive family members under the age of 20 years had higher ICA levels than the older ones [median 18 (range 3–514) JDF units vs. 10 (range 3–564) JDF units; p = 0.008]. Among the adult relatives (≧20 years of age) antibody-positive females had higher ICA levels than the males [median 10 (range 5–564) JDF units vs. 9 (range 3–130) JDF units; p = 0.04]. Siblings had an increased frequency of high-titre ICA (≧18 JDF units) when compared to the parents (4.8 vs. 3.2%; p = 0.05). Among siblings, we found a higher frequency of ICA positivity in brothers than in sisters (10.8 vs. 6.9%; p = 0.01), and this was also true for high-titre ICA (6.0 vs. 3.8 %; p = 0.04). Geographically, the highest ICA prevalence was seen among relatives living in the middle of Finland (10.4 vs. 7.2% in the other parts of Finland; p = 0.01). Conclusions: These results imply that male gender and young age favour positive ICA reactivity among family members of children with T1D. Siblings test positive for high ICA titres (≧18 JDF units) more frequently than parents. Accordingly, judged from demographic characteristics, the yield of ICA screening in first-degree relatives would be maximized by targeting young brothers of affected cases.

Relation between course of disease in type 1 diabetes and islet cell antibodies.

The aim of this study was to estimate the possibility of predicting the course of type 1 diabetes. We analyzed the importance of islet cell antibody levels and residual beta cell function in 46 newly diagnosed patients with diabetes. Islet cell antibodies (ICAs; Juvenile Diabetes Foundation [JDF] units) were determined at the time of diagnosis by the indirect immunofluorescent method. beta cell function was estimated by C peptide levels (nmol/L) before and after glucagon stimulation at the time of clinical remission. Of the 46 patients, 13 were ICA negative (group A). Among ICA-positive patients, ICAs were < 20 JDF units (group B) in 15, between 20 and 80 JDF in 9 (group C), and > 80 JDF in 9 (group D). In group A, 9 patients had clinical remission for 7.5 +/- 1.7 months. Their basal C peptide level was 0.26 +/- 0.05 nmol/L and it increased after stimulation to 44.5 +/- 2.5%. Ten patients in group B had remission for 6.2 +/- 1.5 months. Their basal C peptide levels (0.28 +/- 0.07 nmol/L) were similarly increased after stimulation (47.5 +/- 2.5%). In group C, all patients had remission and it was of the longest duration (14.7 +/- 1.5 months). They had the highest basal C peptide levels (0.45 +/- 0.12 nmol/L) with increases to 57.5 +/- 3.5%. Seven patients in group D with ICA levels > 80 JDF had a short remission (3.2 +/- 1.2 months) despite good basal C peptide levels (0.42 +/- 0.05 nmol/L) and excellent increases after stimulation (92.5%). Our results suggest that moderate levels of ICA are associated with good residual beta cell function and longer remission. Very high ICA levels (> 80 JDF) at the time of diagnosis despite better beta cell function are associated with short clinical remission. Therefore, high ICA levels could be a marker of strong autoimmune reaction and accelerated depletion of beta cell function.

Bone Mineral Density at Time Of Clinical Diagnosis of Adult-Onset Type 1 Diabetes Mellitus

To study bone mineral density (BMD) and bone remodeling factors at the time of diagnosis of adult-onset type 1 diabetes mellitus (DM). In 22 men and 10 women, who ranged in age from 20 to 39 years, a study was undertaken promptly after diagnosis of type 1 DM (on the basis of criteria established by the World Health Organization). Before any treatment, the clinical history, glycemia, ketonuria, basal and glucagon-stimulated C-peptide levels, islet cell antibodies (ICA), glutamic acid decarboxylase autoantibodies (GADA), and bone remodeling variables were recorded for all the study subjects. Dual-energy x-ray absorptiometry (Hologic QDR1000) was performed to measure BMD in the lumbar spine (LS), femoral neck (FN), and Ward's triangle. Of the 32 patients, 24 (75%) showed positive levels of ICA or GADA (or both), whereas 8 (25%) tested negative. The BMD values-Z-scores (standard deviation [SD] adjusted for age and sex)-were lower among the patients with DM than in a matched healthy population in both the LS (-0.61 +/- 1.23 SD; P = 0.008) and the FN (-0.38 +/- 1.00 SD; P = 0.003). Twelve patients had a T-score between -2.5 SD and -1 SD in the LS, and 14 had the same scores in the FN and were classified as having osteopenia. A correlation was found between BMD values and C-peptide levels in the LS (r = 0.231; P = 0.02) and the FN (r = 0.27; P = 0.01). The BMD values did not correlate with bone remodeling markers, hemoglobin A1c, or immunologic variables. We found reduced bone mass in patients with type 1 DM at the time of the clinical diagnosis. A high percentage of patients with DM have osteopenia, which may not, therefore, be a late complication of type 1 DM. These findings need to be confirmed in larger studies.

Evaluation of the efficacy of the combination of multiple autoantibodies to islet-specific antigens in Korean type 1 diabetic patients.

With the recent cloning and recombinant expression of novel islet autoantigens, it is possible to investigate whether the quantitative expression of autoantibodies to these molecules is correlated with the semiquantitative titration of islet cell antibodies (ICA). To estimate the regional difference in the degree of association between these autoantibodies, autoantibodies reacting with ICA512/IA-2 (ICA512) and GAD65 in addition to ICA were analyzed in 131 Korean children with type 1 diabetes. Among the 131 type 1 diabetes patients, 36% was ICA512-positive, 56% was anti-GAD65-positive, and 43% was ICA-positive. However, in a subset of these with recent onset (<1 year), the prevalences of ICA512, anti-GAD65, and ICA were 75%, 75%, and 87.5%, respectively. ICA512 as well as anti-GAD65 were significantly associated with the presence of ICA. Among type 1 diabetes patients, 69% had one or more and 43% had two or more of these autoantibodies. Autoantibodies to ICA512 and anti-GAD65 were observed in 40 and in 41 of 56 ICA-positive subjects, respectively. Furthermore, ICA512 or anti-GAD65 were positive in 97% (34 of 35) and 100% (22 of 22) of patients with ICA levels > or =20 JDF-u and > or =40 JDF-u, respectively. The titer of ICA correlated with those of ICA512 (r=0.41, p<0.001) and anti-GAD65 (r=0.49, p<0.001). Both the prevalences and the titers of ICA512 or anti-GAD65 were strongly correlated with those of ICA even in Korean type 1 diabetes patients. ICA512 and anti-GAD65 in combination may be considered to be an alternative to ICA.

Prognostic factors for the course of beta cell function in autoimmune diabetes.

This study presents a 2-yr follow-up of 281 patients, aged 15-34 yr, diagnosed with diabetes between 1992 and 1993. At diagnosis, 224 (80%) patients were positive for at least one of the following autoantibodies: islet cell antibodies (ICAs), glutamic acid decarboxylase antibodies (GADAs), or tyrosine phosphatase antibodies (IA-2As); the remaining 57 (20%) patients were negative for all three autoantibodies. At diagnosis, C-peptide levels were lower (0. 27; 0.16-0.40 nmol/L) in autoantibody-positive patients compared with autoantibody-negative patients (0.51; 0.28-0.78 nmol/L; P: < 0. 001). After 2 yr, C-peptide levels had decreased significantly in patients with autoimmune diabetes (0.20; 0.10-0.37 nmol/L; P: = 0. 0018), but not in autoantibody-negative patients. In patients with autoimmune diabetes, a low initial level of C-peptide (odds ratio, 2. 6; 95% confidence interval, 1.7-4.0) and a high level of GADAs (odds ratio, 2.5; 95% confidence interval, 1.1-5.7) were risk factors for a C-peptide level below the reference level of 0.25 nmol/L 2 yr after diagnosis. Body mass index had a significant effect in the multivariate analysis only when initial C-peptide was not considered. Factors such as age, gender, levels of ICA or IA-2A or insulin autoantibodies (analyzed in a subset of 180 patients) had no effect on the decrease in beta-cell function. It is concluded that the absence of pancreatic islet autoantibodies at diagnosis were highly predictive for a maintained beta-cell function during the 2 yr after diagnosis, whereas high levels of GADA indicated a course of decreased beta-cell function with low levels of C-peptide. In autoimmune diabetes, an initial low level of C-peptide was a strong risk factor for a decrease in beta-cell function and conversely high C-peptide levels were protective. Other factors such as age, gender, body mass index, levels of ICA, IA-2A or IAA had no prognostic importance.

Glutamic acid decarboxylase antibodies (GADA) is the most important factor for prediction of insulin therapy within 3 years in young adult diabetic patients not classified as Type 1 diabetes on clinical grounds.

Differentiation between Type 1 and Type 2 diabetes in adults is difficult at diagnosis. In this study we tested the hypothesis that autoantibodies at diagnosis are predictive for insulin treatment within 3 years in patients initially not classified as Type 1 diabetes. In a nationwide population-based study, blood samples were obtained from 764 patients, all diagnosed with diabetes during a 2-year period. At diagnosis, 583 (76%) were classified as Type 1, 110 (14%) as Type 2 and 71 (9.3%) could not be classified. Among patients not classified as Type 1 diabetes, 52 (47%) of Type 2 and 42 (59%) of unclassified patients were positive for islet cell antibodies (ICA), glutamic acid decarboxylase antibodies (GADA) or tyrosine phosphatase antibodies (IA-2A). These patients (n=94) had lower body mass index (BMI) (p<0.001) and lower C-peptide (p<0.001) compared to the autoantibody negative patients (n=87). Compared to clinically classified Type 1 diabetes patients positive for autoantibodies (n=477), they have higher BMI (p<0.001), higher C-peptide (p<0.001) and the same levels of ICA, GADA and IA-2A. After 3 years, 93% of autoantibody positive patients initially not classified as Type 1 were on insulin. When ICA, GADA, IA-2A, BMI and C-peptide were tested in a multiple logistic regression, only GADA was significant for insulin treatment within 3 years (OR=18.8; 95% CI 1.8-191) in patients treated with diet or oral drugs at diagnosis. A correct classification is difficult in adult diabetic patients. The presence of pancreatic autoantibodies, especially GADA, at diagnosis of diabetes are highly predictive for insulin therapy within 3 years from diagnosis.

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. Siblings carrying the protective DR2 and DQB1*0602-3 alleles were characterized by lower frequencies of islet cell antibodies (ICA), antibodies to IA-2 (IA-2A), and GADA. Higher levels of ICA were related to HLA identity, the DR4 and DQB1*0302 alleles, and the susceptible DQB1 genotypes, while no significant differences were observed in the levels of IA-2A, GADA, or insulin autoantibodies among siblings with different HLA risk markers. The DR2 or DQB1*0602-3 alleles were not related to the levels of any antibody specificity. A combination of the genetic markers and autoantibodies increased the positive predictive values of all autoantibodies substantially, which may have clinical implications when evaluating the risk of developing type 1 diabetes at the individual level or when recruiting high-risk individuals for intervention trials. However, because such combinations also resulted in reduced sensitivity, autoantibodies alone rather than in combination with genetic markers are recommended as the first-line screening in siblings. Finally, not all siblings with a broad humoral autoimmune response or high-risk genetic markers present with type 1 diabetes, while some with a low genetic risk and weak initial signs of humoral autoimmunity may progress to disease.

Progression to diabetes in relatives with islet autoantibodies. Is it inevitable?

A large cohort of family members with islet cell antibodies (ICA) > or = 20 Juvenile Diabetes Foundation units (JDF U) was examined to determine whether there was a subgroup at low risk of progression to diabetes; whether risk of progression changed over time; and whether rate of progression to diabetes varied according to age, islet autoantibodies, and genetic markers of susceptibility. Individuals with ICA > or = 20 JDF U were identified from 4,423 family members recruited to prospective family studies in the U.K. Subjects were followed for up to 18 years. Antibodies to insulin, GAD, and IA-2 were measured in the first sample, and HLA class II typing was performed. Of 147 family members with ICA > or = 20 JDF U on at least one occasion, 29 developed type 1 diabetes after a median of 3.2 years (maximum 18.1). The cumulative risk of developing diabetes within 15 years was 47% (95% CI 28-67) for all family members with ICA > or = 20 JDF U, 2.8% (0-8.2) for those with ICA alone, and 66% (44-87) for those with at least one additional autoantibody marker. There were no differences in age, HLA class II type, or levels of ICA, insulin autoantibodies, or IA-2 antibodies between those who developed diabetes within 5 years of testing and those who developed diabetes after this time. GAD antibody levels we ..., however, higher in those who progressed more slowly. Family members with ICA alone are at low risk of progression to diabetes. Rapid development of disease after ICA detection could not be distinguished from delayed development on the basis of autoantibodies or markers of genetic susceptibility, and those with multiple antibodies remained at high risk throughout long-term follow-up. This suggests that all family members with multiple islet autoantibodies are destined to develop autoimmune diabetes.

The combination of antibodies to GAD-65 and IA-2ic can replace the islet-cell antibody assay to identify subjects at risk of type 1 diabetes mellitus.

First-degree relatives of type 1 diabetic patients are at increased risk of developing diabetes and, until recently, islet cell antibodies (ICA) have represented the major risk marker used for identification of individuals at increased risk for subsequent progression to diabetes. In order to determine the value of antibodies to GAD-65 and IA-2ic to identify individuals at high risk for type 1 diabetes mellitus, we measured both autoantibodies and ICA in 1436 first-degree relatives of patients with type 1 diabetes. In addition, the sera were analyzed for thyroid, adrenal and gastric-parietal cell autoantibodies as markers for possible polyendocrine involvement. GAD-65 Abs were found in 135 out of 1436 (9.4%) first-degree relatives and in 57 of 98 (58.2%) ICA-positive subjects. IA-2ic were detected in 52 of 1436 (3.6%) first-degree relatives and in 44 of 98 (44.8%) ICA-positive relatives. IA-2ic and/or GAD-65 were detected in 73 of 98 (74.5%) ICA-positive relatives. Interestingly, antibodies to GAD-65 and/or IA-2ic were present in 91.2% of individuals with more than 20JDF-units. Anti-IA-2ic and GAD-65 were positively correlated with high levels of ICA. Anti-IA-2ic and GAD-65 were found in 19% and 48.5% of subjects with ICA levels of 5-20JDF-u but in 68.8% and 76.5% of individuals with ICA of 40JDF-u or more, respectively (p < 0.001), compared to subjects with ICA levels less than 5 JDF-u. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring and siblings had a higher frequency of ICA and IA-2ic (p<0.05) than the subgroup of parents. A significant association was observed between IA-2ic and thyroid antibodies. In addition, higher levels of IA-2ic were found in relatives with positive TPO antibodies (p < 0.001); this correlation was particularly strong in offspring and siblings (p < 0.01). Determination of GAD-65 and IA-2ic antibodies may be considered as an alternative to primary ICA-screening, enabling the screening of large populations.

Islet cell antibodies are less predictive of IDDM among unaffected children in the general population than in sibs of children with diabetes. The Childhood Diabetes in Finland Study Group.

To examine the controversial issue of whether islet cell antibodies (ICAs) have a higher predictive value for progression to clinical IDDM in first-degree relatives of patients with diabetes than in the general population. ICAs were analyzed with standard immunofluorescence in two population-based groups: 765 sibs of children with recent-onset diabetes and 1,212 unaffected Finnish children <20 years of age at initial screening. Those positive for ICAs were additionally tested for antibodies to GAD (GADAs) and the protein tyrosine phosphatase-related IA-2 antigen (IA-2As). Subsequently, these subjects were observed for the manifestation of clinical IDDM over the next 7 years. The frequency of both detectable ICAs and ICA levels > or =20 Juvenile Diabetes Foundation units (JDF U) was significantly higher among the sibs than in the general population (7.8 vs. 4.1% and 4.8 vs. 2.0%, respectively; P < 0.001). The prevalence of GADAs (37/60 vs. 3/48; P < 0.001) and IA-2As (31/60 vs. 0/48; P < 0.001) was increased among ICA-positive sibs compared with ICA-positive individuals from the background population. Over the next 7 years, 24 sibs (3.1%) and 3 unrelated children positive for ICAs (0.3%) progressed to clinical diabetes. The positive predictive value of ICAs was thus 6% in the general population and 40% among the sibs (P < 0.001), or 13 and 59%, respectively (P < 0.001), with an antibody cutoff level of 20 JDF U. The positive predictive value was related to the number of positive autoantibodies in sibs, which was 57% in those with three antibodies, 50% in those with two antibodies, and only 6% in those with ICAs alone. These data show that the frequency of multiple autoantibodies is substantially lower in ICA-positive children representing the general population than in ICA-positive sibs of children with IDDM. As a consequence, the predictive value of ICAs for IDDM is higher in sibs of affected children than in the general population. This finding must be taken into account when planning intervention trials aimed at preventing or delaying the manifestation of clinical diabetes in individuals from the general population who test positive for ICAs.

Several different enterovirus serotypes can be associated with prediabetic autoimmune episodes and onset of overt IDDM. Childhood Diabetes in Finland (DiMe) Study Group.

In a prospective multicentre study described previously on prediabetic events in siblings of index cases with insulin-dependent diabetes mellitus, 31 children developed clinical diabetes during the observation period and 51 children seroconverted for islet cell antibodies or insulin autoantibodies. By using nonserotype specific EIA and RIA, it has shown recently that enterovirus infections in both groups were frequently associated with increases of islet cell antibody and/or insulin autoantibody titres. Serum specimens sequentially collected from 12 children during the prediabetic period were still available and were then tested for serotype-specific neutralizing antibodies. Plaque-neutralization assays were carried out for coxsackievirus A9, coxsackievirus B types 1 to 6, and echovirus types 1 and 11. An unequivocal monotypic increase in neutralizing antibodies was observed on seven occasions in six children, on one occasion with coxsackievirus A9, one with coxsackievirus B1, two with coxsackievirus B2, two with coxsackievirus B3, and one with coxsackievirus B5. In four patients, the infection was associated temporally with increases in the levels of islet cell antibodies, insulin autoantibodies and/or antibodies to glutamic acid decarboxylase, and in three other patients, it coincided with the clinical onset of insulin-dependent diabetes mellitus. These results suggest that the association of enterovirus infections with insulin-dependent diabetes mellitus is not restricted to serotype 4 of coxsackie B viruses suspected previously, but that several different serotypes might play a role in the pathogenesis of the disease.

The Melbourne Pre-Diabetes Study: prediction of type 1 diabetes mellitus using antibody and metabolic testing.

To determine the utility of various autoantibodies in predicting progression to clinical diabetes in first-degree relatives of patients with type 1 diabetes mellitus. 3315 first-degree relatives of patients with type 1 diabetes (1161 parents, 1206 siblings and 948 offspring) recruited through diabetes clinics, private endocrinologists, Diabetes Australia and the Juvenile Diabetes Foundation. Prevalence of islet cell antibodies (ICA) levels > or = 20 JDFu, insulin autoantibodies (IAA) levels > 100 nU/mL, and antibodies to glutamic acid decarboxylase (GADAb) and tyrosine phosphatase IA2 (IA2Ab); change in beta cell function over time; and development of clinical diabetes. 2.6% of relatives had elevated ICA levels, 1.3% had elevated IAA levels and 0.3% had both. High ICA levels were significantly more frequent in siblings than in offspring or parents, and were more frequent in relatives younger than 20 years. GADAb were detected in 68% and IA2Ab in 57% of relatives with elevated ICA and/or IAA levels. Diabetes developed in 33 relatives (25 siblings, 2 offspring and 6 parents). Before diagnosis of clinical diabetes, high ICA levels were detected in 18 (58%), high IAA levels in 7 (23%), both in 5 (15%), and either in 19 (61%); GADAb were detected in 26 (84%), IA2Ab in 13 (42%), both in 11 (35%), and either in 28 (90%). First phase insulin release (FPIR) less than 50 mU/L was very strongly associated with progression to diabetes. In relatives with FPIR initially greater than 50 mU/L who eventually developed diabetes, there was a gradual and continuous reduction in FPIR over time before diagnosis. Type 1 diabetes can be diagnosed in the preclinical stage. The recently described antibodies to glutamic acid decarboxylase and tyrosine phosphatase IA2 appear superior to ICA as screening tools for the preclinical diagnosis of type 1 diabetes.

Systemic bias of cytokine production toward cell-mediated immune regulation in IDDM and toward humoral immunity in Graves' disease.

Disturbed immune regulation has been postulated to be crucial in the pathogenesis of IDDM and other autoimmune or allergic diseases. We therefore tested the hypothesis of a general bias in the peripheral immune system in patients with recent-onset IDDM or Graves' disease in comparison to healthy control subjects by studying whole blood cultures stimulated with phytohemagglutinin. Cells from IDDM patients (n = 53) produced significantly higher amounts of Th1 cytokines gamma-interferon (IFN-gamma) (P = 0.028) and tumor necrosis factor alpha (TNF-alpha) (P = 0.007) than normal control subjects (n = 56), while Th2 cytokine levels (interleukin [IL]-4, IL-10) were similar. Low levels of islet cell antibodies (ICAs) in IDDM patients were associated with high levels of Th1 and Th2 cytokines. Antibodies to GAD, ICA512, or insulin did not correlate with individual cytokine profiles. Also, HLA-DQ types did not significantly correlate with either Th1 or Th2 cytokine production. Conversely, whole blood cultures from patients with Graves' disease (n = 18) produced significantly less TNF-alpha and IL-4 than normal subjects (P = 0.001-0.006). However, when the balance between Th1 and Th2 cytokine production was analyzed in individuals, the ratio between IFN-gamma or TNF-alpha and IL-4 or IL-10 was clearly biased toward Th1 reactivity in patients with IDDM (P = 0.0001), while a dominance of Th2 cytokine production was seen in Graves' disease (P = 0.0001). The ratio of counterregulatory cytokines appeared to be the most reliable marker of the individual disease process. This study provides first evidence of a systemic bias in the immune regulation of humans, which might be either toward cell-mediated immunity (Th1) in IDDM or humoral immunity (Th2) in Graves' disease.