Signs of beta-cell autoimmunity in nondiabetic schoolchildren: a comparison between Russian Karelia with a low incidence of type 1 diabetes and Finland with a high incidence rate

OBJECTIVE: We sought to study the prevalence of autoantibodies to various islet cell antigens in the background population of two neighboring countries with a sixfold difference in the incidence of type 1 diabetes. RESEARCH DESIGN AND METHODS: Serum samples were obtained from 3,652 nondiabetic schoolchildren in Finland and from 1,988 schoolchildren in the adjacent Karelian Republic of Russia. The Karelian children were divided into three groups (Finns/Karelians, Russians, and others) based on the ethnic background of their mother. The samples were analyzed for islet cell antibodies (ICAs), insulin autoantibodies (IAAs), GAD antibodies (GADAs), and the tyrosine phosphatase-like insulinoma antigen 2 (IA-2A) protein and HLA class II genotypes. RESULTS: The frequency of ICAs, IAAs, and GADAs did not differ significantly between the Karelian (3.5, 0.6, and 0.9%, respectively) and Finnish children (2.8, 0.9, and 0.5%, respectively). Similarly, the frequency of multiple (> or = 2) autoantibodies was similar in both countries (0.5 vs. 0.6%). The frequency of IA-2A was, however, four times higher in Finland (0.6 vs. 0.15% in Russian Karelia; P = 0.03). There were no significant differences in autoantibody prevalence among the three ethnic groups in Russian Karelia. There was a falling frequency of GADAs and of positivity for multiple autoantibodies along with decreasing HLA-conferred disease susceptibility among the Finnish schoolchildren. CONCLUSIONS: These data indicate that beta-cell autoimmunity among schoolchildren is as frequent in Russian Karelia as in Finland, although the incidence of clinical type 1 diabetes is six times higher in Finland. However, in contrast to this general trend, IA-2As were more common in Finland. Since IA-2As usually appear late in the preclinical process, this suggests that progressive beta-cell autoimmunity is more rare in Russian Karelia.     

Autoantibodies to a 38-kDa glycosylated islet cell membrane-associated antigen in (pre)type 1 diabetes: association with IA-2 and islet cell autoantibodies.

OBJECTIVE: To study the association of autoantibodies against a 38-kDa glycated islet cell membrane-associated (GLIMA) protein with (pre)type 1 diabetes, patient characteristics, and other immune and genetic markers of the disease and to evaluate the possible added value of GLIMA antibody determinations for disease prediction and classification. RESEARCH DESIGN AND METHODS: Recent-onset type 1 diabetic patients (n = 100), prediabetic siblings (n = 23), and nondiabetic control subjects (n = 100) were consecutively recruited by the Belgian Diabetes Registry. GLIMA antibodies were determined by immunoprecipitation of radiolabeled islet cell proteins; islet cell antibodies (ICAs) were determined by indirect immunofluorescence; and insulin autoantibodies (IAAs), insulinoma-associated protein-2 antibodies (IA-2As), and GAD antibodies (GADAs) were determined by radioligand assays. RESULTS: GLIMA antibodies were detected in 38% of type 1 diabetic patients and 35% of prediabetic siblings (during follow-up) vs. 0% in control subjects (P < 0.001). Their prevalence was lower than that of other antibodies and was significantly associated with high levels of IA-2A and ICA (P < 0.0001). In (pre)diabetes, GLIMA antibodies could only be demonstrated in sera positive for > or = 1 other autoantibody. CONCLUSIONS: GLIMA antibodies are strongly associated with type 1 diabetes and antibody markers of rapid progression to clinical onset but have a lower diagnostic sensitivity for the disease than IAA, ICA, IA-2A, or GADA. In its present form, the GLIMA antibody assay does not provide much additional information for prediction or classification of diabetes, compared with that obtained from the measurement of IA-2As alone or in combination with IAAs, ICAs, and GADAs.     

Gestational diabetes identifies women at risk for permanent type 1 and type 2 diabetes in fertile age: predictive role of autoantibodies

OBJECTIVE: Our aim was to evaluate the predictive value of gestational diabetes mellitus (GDM), diabetes-associated autoantibodies, and other factors for development of clinical diabetes later in life. RESEARCH DESIGN AND METHODS: In this case-control study the presence of autoantibodies was studied in 435 women with GDM and in healthy matched control subjects. The need for exogenous insulin during GDM was recorded. In the GDM group, the mean follow-up period was 5.7 years and in the control group 6.1 years. RESULTS: Among the subjects with GDM, 20 (4.6%) developed type 1 diabetes and 23 (5.3%) developed type 2 diabetes, whereas none of the control subjects became diabetic. Two-thirds of those who developed type 1 diabetes tested positive initially for islet cell antibodies (ICAs), whereas 56% of them had autoantibodies to GAD (GADAs) and 38% to the protein tyrosine phosphatase-related IA-2 molecule. Only 2 of the 23 women who presented later with type 2 diabetes tested positive for autoantibodies. According to multivariate analysis, initial age < or =30 years, the need for insulin treatment for GDM, and antibody positivity for ICAs and GADAs were associated with increased risk for clinical type 1 diabetes. CONCLUSIONS: Pregnancy seems to identify women who are at risk of developing diabetes later in life. About 10% of Finnish women with GDM will develop diabetes over the next 6 years; nearly half of them develop type 1 diabetes and the other half type 2 diabetes. Age < or =30 years, the need for insulin treatment during pregnancy, and positivity for ICAs and GADAs confer a high risk of subsequent progression to type 1 diabetes in women affected by GDM.     

Zinc Transporter 8 Antibodies Complement GAD and IA-2 Antibodies in the Identification and Characterization of Adult-Onset Autoimmune Diabetes: Non Insulin Requiring Autoimmune Diabetes (NIRAD) 4

OBJECTIVE

Zinc transporter 8 (ZnT8) is an islet β-cell secretory granule membrane protein recently identified as an autoantibody antigen in type 1 diabetes. The aim of this study was to determine the prevalence and role of antibodies to ZnT8 (ZnT8As) in adult-onset diabetes.

RESEARCH DESIGN AND METHODS

ZnT8As were measured by a radioimmunoprecipitation assay using recombinant ZnT8 COOH-terminal or NH²-terminal proteins in 193 patients with adult-onset autoimmune diabetes having antibodies to either GAD (GADAs) or IA-2 (IA-2As) and in 1,056 antibody-negative patients with type 2 diabetes from the Non Insulin Requiring Autoimmune Diabetes (NIRAD) study.

RESULTS

ZnT8As-COOH were detected in 18.6% patients with autoimmune diabetes and 1.4% with type 2 diabetes. ZnT8As-NH² were rare. ZnT8As were associated with younger age and a high GADA titer. The use of GADAs, IA-2As, and ZnT8As in combination allowed a stratification of clinical phenotype, with younger age of onset of diabetes and characteristics of more severe insulin deficiency (higher fasting glucose and A1C, lower BMI, total cholesterol, and triglycerides) in patients with all three markers, with progressive attenuation in patients with two, one, and no antibodies (all P^trend < 0.001). Autoantibody titers, association with high-risk HLA genotypes, and prevalence of thyroid peroxidase antibodies followed the same trend (all P < 0.001).

CONCLUSIONS

ZnT8As are detectable in a proportion of patients with adult-onset autoimmune diabetes and seem to be a valuable marker to differentiate clinical phenotypes.Zinc transporter 8 (ZnT8) is a pancreatic β-cell secretory granule membrane protein that has been recently identified as a target of humoral immunity in type 1 diabetes (1). Autoantibodies to ZnT8 (ZnT8As) constitute an additional marker of autoimmune diabetes, which complement the established antibodies to insulin (IAAs) (2), GAD (GADAs) (3), and protein tyrosine IA-2 (IA-2As) (4). In the first report, ZnT8As were detected in 63% of young patients at onset of disease, overlapping with, but also independent of, GADAs, IAAs, and IA-2As, and the combined use of these four antibody markers raised the detection rate of autoimmunity to 94% in new-onset cases of type 1 diabetes. Moreover, ZnT8As could be detected also in the preclinical phase of type 1 diabetes, showing a trend to a later appearance relative to IAAs, GADAs, and IA-2As but with the ability to identify individuals with a more rapid progression to clinical disease. Although islet autoimmunity is responsible for the large majority of childhood- and adolescent-onset diabetes, it can be found also in 4–10% of adult-onset diabetes. This subgroup of patients test positive for humoral markers of islet autoreactivity, despite having clinical features indistinguishable from those of classic type 2 diabetes, and are characterized as having latent autoimmune diabetes of adult (LADA). Patients with LADA are identified solely by the detection of circulating islet autoantibodies, with islet cell antibodies (ICAs) and GADAs being the antibody markers with the highest prevalence (5,6), followed by IA-2As, which are detected in a minority of case subjects and are almost invariably associated with GADAs (7), whereas insulin autoantibodies, which constitute a specific marker of juvenile diabetes inversely related to age and rare in adults, are unlikely to be useful for LADA screening (8–10). The aim of this study was to evaluate the prevalence of ZnT8As in adult-onset diabetes and establish their potential use as an additional marker of autoimmunity and phenotype characterization in this patient population.     

Prediction of Type 1 Diabetes in the General Population

OBJECTIVE

To evaluate the utility of GAD antibodies (GADAs) and islet antigen-2 antibodies (IA-2As) in prediction of type 1 diabetes over 27 years in the general population and to assess the 6-year rates of seroconversion.

RESEARCH DESIGN AND METHODS

A total of 3,475 nondiabetic subjects aged 3–18 years were sampled in 1980, and 2,375 subjects (68.3%) were resampled in 1986. All subjects were observed for development of diabetes to the end of 2007. GADAs and IA-2As were analyzed in all samples obtained in 1980 and 1986.

RESULTS

A total of 34 individuals (1.0%; 9 developed diabetes) initially had GADAs and 22 (0.6%; 9 developed diabetes) IA-2As. Seven subjects (0.2%) tested positive for both autoantibodies. The positive seroconversion rate over 6 years was 0.4% for GADAs and 0.2% for IA-2As, while the inverse seroconversion rates were 33 and 57%, respectively. Eighteen subjects (0.5%) developed type 1 diabetes after a median pre-diabetic period of 8.6 years (range 0.9–20.3). Initial positivity for GADAs and/or IA-2As had a sensitivity of 61% (95% CI 36–83) for type 1 diabetes. Combined positivity for GADAs and IA-2As had both a specificity and a positive predictive value of 100% (95% CI 59–100).

CONCLUSIONS

One-time screening for GADAs and IA-2As in the general childhood population in Finland would identify ∼60% of those individuals who will develop type 1 diabetes over the next 27 years, and those subjects who have both autoantibodies carry an extremely high risk for diabetes. Both positive and inverse seroconversions do occur over time reflecting a dynamic process of β-cell autoimmunity.Type 1 diabetes is an immune-mediated disease leading to chronic insulin deficiency due to extensive and selective β-cell destruction in subjects with increased genetic disease susceptibility (1). The clinical disease manifestation represents end-stage insulitis, since only 10–20% of the insulin-producing β-cells have been estimated to still be functioning at the time of diagnosis (2). The clinical disease presentation is preceded by an asymptomatic period of variable duration. β-cell autoimmunity is characterized by the presence of autoantibodies, such as islet cell autoantibodies (ICAs), insulin autoantibodies (IAAs), autoantibodies to the 65-kDa isoform of GAD (GADAs), and autoantibodies to the intracellular portion of the protein tyrosine phosphatase–related islet antigen-2 molecule (IA-2As), in the peripheral circulation (3). Many studies (3–5) have shown that these antibodies can be used efficiently for the prediction of type 1 diabetes in first-degree relatives of affected patients. The combination of GADAs and IA-2As has a high sensitivity and specificity for type 1 diabetes in family members, although prospective studies from birth have shown that IAAs are usually the first or among the first antibodies to appear in young children (6–8). In a previous survey, we showed that the predictive characteristics of combined positivity for GADAs and IA-2As were of the same magnitude in the general population as those seen among first-degree relatives over an observation period of 15 years (9). In this study, we set out to assess the predictive characteristics of GADAs and IA-2As over a period of 27 years in a population-based series of 3,475 Finnish subjects initially aged 3–18 years. We also had the opportunity to define in this population the rates of positive and inverse seroconversions over the initial 6 years of follow-up.     

Clinical presentation and early course of type 1 diabetes in patients with and without thyroid autoimmunity

OBJECTIVE: To evaluate the prevalence of thyroid autoimmunity (TAI) in patients with recent-onset type 1 diabetes and to determine the influence of TAI on the clinical presentation and evolution of type 1 diabetes. RESEARCH DESIGN AND METHODS: We studied 111 newly diagnosed type 1 diabetes patients > 13 years old. The diagnosis of TAI was based on medical history and measurement of thyroid peroxidase (microsomal) antibodies (TPOAs). Clinical presentation of diabetes, beta-cell autoimmune markers (GADAs and 1A2As), and evolution of insulin-secretory reserves and metabolic control during the first 2 years of follow-up were analyzed. Differences between groups were evaluated by Student's t test or the chi 2 test. The influence of TAI on follow-up data was evaluated by multiple logistic regression analysis. RESULTS: TAI was present in 31 patients (14 TPOA+ patients with normal thyroid function, 12 TPOA+ patients with thyroid dysfunction, and 5 patients with previously diagnosed TAI). TAI was more prevalent in women than in men (43.7 vs. 15.9%, P = 0.001). beta-Cell autoimmunity was more prevalent in patients with TAI than in those without TAI (93.5 vs. 76.3%, P = 0.03). The evolution of insulin requirements, metabolic control, and insulin-secretory reserves was comparable in the two groups. CONCLUSIONS: TAI is present in many type 1 diabetes patients at the time of diagnosis and is associated with a high prevalence of thyroid dysfunction. The clinical presentation of diabetes and the evolution of metabolic control and insulin-secretory reserves are not influenced by the presence of TAI. Patients with type 1 diabetes should be screened for TAI at diagnosis.     

β-Cell Autoimmunity in Pediatric Celiac Disease: The Case for Routine Screening?

OBJECTIVE—To evaluate the prevalence of β-cell autoimmunity and the usefulness of a type 1 diabetes screening in patients with celiac disease.RESEARCH DESIGN AND METHODS—We measured GAD antibodies (GADAs), insulinoma-associated protein 2 antigens (IA-2As), and insulin autoantibodies (IAAs) in 188 young Italian patients with celiac disease (66 male [35.1%]). Mean age at celiac disease diagnosis was 5.4 years (0.5–17.1), and mean celiac disease duration was 4.2 years (0–28.8). Celiac disease was diagnosed by jejunal biopsy after positivity for endomysial and tissue transglutaminase antibody was confirmed.RESULTS—GADAs were positive in seven patients (3.7%), and IA-2As were positive in two patients. IAAs were negative in all cases. Metabolic evaluation was normal, and no patients developed diabetes during follow-up. There was no significant association among β-cell autoimmunity and sex, age, pubertal stage, family history, or coexistence of other autoimmune disorders; compliance to a gluten-free diet was confirmed.CONCLUSIONS—Our results showed a low prevalence of β-cell autoimmunity and do not support a precocious screening for β-cell autoimmunity in young celiac disease patients.Celiac disease, whose prevalence in the general Western population is about 1%, is associated with other autoimmune disorders (1). Type 1 diabetes and celiac disease share a prodromic period, with autoantibodies to islet or gut antigens. Antibodies to GAD (GADAs), to insulinoma-associated protein 2 antigen (IA-2A), and anti-insulin (insulin autoantibody [IAA]) are used for type 1 diabetes screening; antiendomysial antibodies (EMAs) and endomysial tissue transglutaminase antibodies (tTGAs) are recommended for celiac disease screening (2,3). Few reports investigated β-cell autoimmunity in celiac disease patients (4,5). We evaluated the frequency of β-cell autoimmunity and the usefulness of type 1 diabetes screening in young celiac disease patients.     

The high prevalence of autoantibodies to tissue transglutaminase in first-degree relatives of patients with type 1 diabetes is not associated with islet autoimmunity

OBJECTIVE: To determine the extent of celiac autoimmunity in type 1 diabetic patients and the overlap between islet and celiac autoimmunity in their nondiabetic relatives. RESEARCH DESIGN AND METHODS: IgA antibodies to tissue transglutaminase were determined in serum taken from 433 type 1 diabetic patients and 1,442 nondiabetic first-degree relatives. Samples with transglutaminase antibodies above the 97.5th percentile of 347 schoolchildren were also assayed for IgA anti-endomysial antibodies (EMAs). Markers of islet autoimmunity (islet cell antibodies and autoantibodies to insulin, glutamate decarboxylase. and protein tyrosine phosphatase IA-2) had previously been measured in all relatives. RESULTS: In the absence of known celiac disease, the prevalence of transglutaminase antibody levels above the 97.5th percentile of the schoolchildren was 13.4% in diabetic patients and 7.0% in nondiabetic relatives. ENMAs were found in addition to transglutaminase antibodies in 2.6% of probands and in 1.9% of first-degree relatives, but none of the schoolchildren. Transglutaminase antibodies were found to persist in 10 of 30 patients and in 30 of 59 relatives with follow-up samples taken at least 2 years after the initial sample. Of 186 nondiabetic relatives with islet autoantibodies, only 10 also had transglutaminase antibodies. CONCLUSIONS: We found a high prevalence of celiac autoimmunity in patients and first-degree relatives of children with type 1 diabetes, but we found limited overlap between islet and celiac autoimmunity in nondiabetic relatives. The high prevalence of celiac autoimmunity may be explained by shared genetic susceptibility and identifies a population within which screening for the disease may be justified.     

Incidence and significance of islet cell antibodies in women with previous gestational diabetes

Islet cell antibodies (ICAs) are markers for patients at risk for insulin-dependent diabetes and are associated with progressive beta-cell destruction. This prospective study was performed to estimate the incidence of these antibodies in 187 women with previous gestational diabetes. With a specific protein A monoclonal antibody (MoAb) assay, the incidence of ICAs was only 1.6% (3 of 187). Oral and intravenous glucose tolerance tests were performed in these 3 women and compared with 6 women with previous gestational diabetes without ICAs and 5 control women. Glucose tolerance was impaired only in the 3 women with ICAs, who also had an increase (P less than 0.03) in fasting plasma glucose and a decrease (P less than 0.03) in early first-phase insulin response. We conclude that the more specific MoAb method indicates a lower incidence of ICA in women with a history of gestational diabetes than previously reported and that a decreased first-phase insulin response is associated with the presence of ICAs, suggesting progressive islet cell damage.     

Antibodies to a 64,000 Mr human islet cell antigen precede the clinical onset of insulin-dependent diabetes.

Antibodies in sera from newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients are directed to a human islet cell protein of relative molecular mass (Mr) 64,000. Since IDDM seems to develop after a prodromal period of beta-cell autoimmunity, this study has examined whether 64,000 Mr antibodies could be detected in 14 individuals who subsequently developed IDDM and five first degree relatives who have indications of altered beta-cell function. Sera were screened by immunoprecipitation on total detergent lysates of human islets and positive sera retested on membrane protein preparations. Antibodies to the 64,000 Mr membrane protein were consistently detected in 11/14 IDDM patients, and in all 5 first degree relatives. 10 IDDM patients were already positive in the first samples, obtained 4-91 mo before the clinical onset of IDDM, whereas 1 patient progressed to a high 64,000 Mr immunoreactivity, at a time where a commencement of a decline in beta-cell function was detected. 64,000 Mr antibodies were detected before islet cell cytoplasmic antibodies (ICCA) in two patients. In the control groups of 21 healthy individuals, 36 patients with diseases of the thyroid and 5 SLE patients, the 64,000 Mr antibodies were detected in only one individual, who was a healthy sibling to an IDDM patient. These results suggest that antibodies against the Mr 64,000 human islet protein are an early marker of beta-cell autoimmunity and may be useful to predict a later development of IDDM.     

Comparative analysis of organ-specific autoantibodies and celiac disease--associated antibodies in type 1 diabetic patients, their first-degree relatives, and healthy control subjects

OBJECTIVE: In type 1 diabetes the coexistence with other endocrine diseases and organ-specific autoantibodies has been frequently reported leading to the concept of autoimmune polyendocrine syndrome (APS). In addition, an association of type 1 diabetes with celiac disease has been described. These disorders share a similar genetic background, and first-degree relatives of type 1 diabetic patients may also be affected significantly. Screening for specific antibodies allows early diagnosis of these disorders. RESEARCH DESIGN AND METHODS: In the present cross-sectional study, we analyzed sera from 197 recent-onset type 1 diabetic patients at the time of diagnosis, 882 first-degree relatives, and sera of 150 healthy control subjects for prevalence and co-occurence of the following antibodies (method): insulin autoantibodies (radioimmunoassay); GAD and IA-2 antibodies (radioligand assay); islet cell antibody, anti-adrenal cortex antibodies, and anti-gastric parietal cell antibodies (indirect immunofluorescence); anti-thyroglobulin and anti-thyroid peroxidase antibodies; and gliadin IgG/A and tissue-transglutaminase IgA (enzyme-linked immunosorbent assay). RESULTS: The overall frequency of gastric patietal cell antibodies and adrenal antibodies did not differ significantly among groups. In contrast, type 1 diabetes-associated antibodies and thyroid antibodies were significantly more frequent both in recent-onset type 1 diabetic patients and in the group of first-degree relatives (P < 0.05). The prevalence of gliadin IgG/IgA and transglutaminase IgA was significantly higher in the group of recent-onset type 1 diabetic patients (P < 0.05), but the difference between first-degree relatives and control subjects did not reach statistical significance. Focusing on the coexistence of antibodies, the group of recentonset type 1 diabetic patients presented with 27.4% of the subjects testing antibody-positive-specific for two or more of the envisaged disorders (i.e., type 1 diabetes, autoimmune thyroiditis, and celiac disease) compared with 3.1% in the group of first-degree relatives and 0 of 150 in the control population (P < 0.05). CONCLUSIONS: We conclude that, in an active case-finding strategy, recent-onset type 1 diabetic patients should be routinely screened at least for concomitant autoimmune thyroid disease and additionally for celiac disease. Screening in their first-degree relatives should include at a minimum the search for thyroid autoimmunity in addition to screening for pre-type 1 diabetes.     

Autoantibodies to REG, a beta-cell regeneration factor, in diabetic patients

BACKGROUND: Regenerating gene (Reg) product, Reg, acts as an autocrine/paracrine growth factor for beta-cell regeneration. The presence of autoimmunity against REG may affect the operative of the regenerative mechanisms in beta cells of Type 1 and Type 2 diabetes patients. We screened sera from Type 1 and Type 2 diabetes subjects for anti-REG autoantibodies, searched for correlations in the general characteristics of the subjects with the presence of anti-REG autoimmunity, and tested the attenuation of REG-induced beta-cell proliferation by the autoanitibodies. MATERIAL AND METHODS: We examined the occurrence of anti-REG autoantibodies in patients' sera (265 Type 1, 368 Type 2 diabetes patients, and 75 unrelated control subjects) by Western blot analysis, and evaluated inhibitory effects of the sera on REG-stimulated beta-cell proliferation by a 5'-Bromo-2'-deoxyuridine (BrdU) incorporation assay in vitro. RESULTS: Anti-REG autoantibodies were found in 24.9% of Type 1, 14.9% of Type 2 and 2.7% of control subjects (P = 0.0004). There were significant differences between the autoantibody positive and negative groups in the duration of disease in the Type 1 subjects (P = 0.0035), and the age of onset in the Type 2 subjects (P = 0.0274). The patient sera containing anti-REG autoantibodies significantly attenuated the BrdU incorporation by REG (35.6 +/- 4.06% of the control), whereas the nondiabetic sera without anti-REG autoantibodies scarcely reduced the incorporation (88.8 +/- 5.10%). CONCLUSION: Anti-REG autoantibodies, which retard beta-cell proliferation in vitro, are found in some diabetic patients. Thus, autoimmunity to REG may be associated with the development/acceleration of diabetes in at least some patients.     

Lack of association between early childhood immunizations and beta-cell autoimmunity.

OBJECTIVE: To determine whether early childhood immunization history affects the risk of developing the beta-cell autoimmunity that precedes type 1 diabetes. RESEARCH DESIGN AND METHODS: This article describes a case-control study whose participants were 317 children aged < or = 12 years who have a first-degree relative with type 1 diabetes. The children were enrolled in a prospective cohort study of the etiology of beta-cell autoimmunity, the Diabetes Autoimmunity Study in the Young, in Denver, Colorado. The main outcome measure was beta-cell autoimmunity as determined by persistent autoantibodies against insulin, GAD, or islet cell antibody (IA-2) 512. The number of cases with beta-cell autoimmunity was 25, and the number of control subjects (the remainder of the cohort) was 292. RESULTS: There was no difference between cases and control subjects in the proportion receiving hepatitis B (HBV), Haemophilus influenzae b (Hib), polio, or diphtheria tetanus pertussis (DTP) vaccines before 9 months of age; in the proportion receiving HBV at birth rather than later; or in the median age at first HBV, Hib, polio, or DTP vaccination. CONCLUSIONS: The results suggest that changing the early childhood immunization schedule would not affect the risk of developing beta-cell autoimmunity or type 1 diabetes.     

Optimized autoantibody-based risk assessment in family members. Implications for future intervention trials.

OBJECTIVE: To determine the best autoantibody-based testing strategy for recruiting relatives for future intervention trials and to establish the role of islet cell antibodies (ICAs) within this strategy. RESEARCH DESIGN AND METHODS: ICAs, insulin autoantibodies (IAAs), GAD antibodies, and IA-2 antibodies were determined in serum samples at study entry of 3,655 non-diabetic first-degree relatives of patients with type 1 diabetes who were followed for a median of 5.5 years. The cumulative risk of diabetes associated with single and combined antibody marker levels of > or = 97.5th percentile in schoolchildren was calculated by using life-table analysis. RESULTS: Of the 26 relatives who developed insulin-requiring diabetes during follow-up, 16 were aged < 20 years and 7 were aged 20-39 years at study entry. Of the 23 cases aged < 40 years, 83% had IA-2 and/or GAD antibodies, and 87% had IAA and/or GAD antibodies > or = 97.5th percentile compared with 61% who had ICAs of > or = 5 Juvenile Diabetes Foundation units (JDF U). A two-step strategy with parallel testing for IA-2/GAD antibodies followed by IAA testing identified 50% of cases aged < 20 years and was associated with a 71% risk within 10 years. In subjects aged 20-39 years, this strategy conferred a 51% risk, whereas using ICAs as the second test gave 86% sensitivity and a 74% risk. Primary screening for IA-2 and/or GAD antibodies followed by testing for IAA and/or ICA antibodies achieved the highest sensitivity in both age-groups and conferred a 63% risk. In contrast, ICAs of > or = 20 JDF U (the inclusion criteria for the European Nicotinamide Diabetes Intervention Trial) gave 48% sensitivity and 35% risk. CONCLUSIONS: ICA testing can be replaced as a primary screening measure by IA-2/GAD or IAA/GAD antibody testing. The sensitivity of ICAs (used alone or in combination with IAAs) gives them a useful role in second-line testing. Combination testing could reduce the size of screening populations needed for recruitment in future intervention trials by approximately 50% compared with testing based on ICAs alone.     

Autoimmunity against pancreatic islets and other tissues before and after interferon-alpha therapy in patients with hepatitis C virus chronic infection

OBJECTIVE: The aim of the study was to investigate the prevalence of clinical and latent autoimmune diseases in Italian patients with hepatitis C virus (HCV) chronic infection before and after treatment with interferon-alpha (IFN-alpha). RESEARCH DESIGN AND METHODS: The evidence of clinical autoimmune disease and the presence of autoantibodies were assessed in 70 patients with HCV chronic infection. Autoantibodies to islet cell (ICA), glucagon-producing cells (GCA), parietal cell (PCA), adrenal cortex (ACA), adrenal medulla (AdMA), nuclei (ANA), liver-kidney microsomal (LKM-Ab), mitochondrial, and smooth muscle (SMA) were tested using the classic indirect immunofluorescence technique. Autoantibodies to GAD (GADAb), second islet cell autoantigen (IA2-Ab), and insulin (IAA) were tested by radioimmunoassay and thyroid microsomal autoantibodies (TMHA) and thyroglobulin autoantibodies (TGHA) were assessed by hemoagglutination test. RESULTS: None of the 70 patients studied showed evidence of clinical disease before treatment with IFN-alpha. However, 1 (1.4%) patient was positive for ICA, 2 (2.8%) were positive for GCA, 2 (2.8%) for GADAb, 5 (7.1%) for PCA, 2 (2.8%) for ANA, 3 (3.7%) for SMA, 4 (5.7%) for TMHA, and 2 (2.8%) for TGHA. These frequencies were not significantly different when compared with healthy control subjects. There were 29 (41%) patients who were positive for IAA at low titers compared with 2% of the control subjects (significantly different P < 0.0001). ICA titers of one patient positive for ICA/GADAb increased during the IFN-alpha therapy, and the patient developed type 1 diabetes 5 months after the beginning of treatment. IAA levels did not change during the course of treatment, and none of the IAA+ patients developed diabetes. Thyroid autoantibody titers increased in 3 of the 4 initially positive patients, with 1 patient becoming positive and 2 thyroid antibody-positive patients developing overt hypothyroidism during IFN-alpha treatment. PCA titers increased in 1 of 5 positive patients. Antibodies to other autoantigens did not change during the course of treatment. CONCLUSIONS: We have not found an increased frequency of clinical or latent autoimmune diseases in patients with chronic HCV infection. However, this study suggests that screening patients for autoantibodies (in particular, thyroid and pancreas) before and during IFN-alpha therapy may be useful in assessing the risk of patients developing autoimmune disease.     

Crucial points at diagnosis. Type 2 diabetes or slow type 1 diabetes

Two major types of diabetes have been recognized since the late 1930s. However, in recent times there have been major changes in classification and understanding of these types, including improved knowledge of maturity-onset diabetes in the young, with the identification of mutations relating to impaired insulin secretion and the recognition of slow-onset type 1 diabetes in adults now designated as latent autoimmune diabetes in adults (LADA). A major problem area in diabetes classification concerns cases of slowly progressive forms of type 1 and type 2 diabetes, particularly in adults aged 25-50 years. This is a more contemporary problem because cases of type 2 diabetes are presenting at an increasingly younger age. In the landmark U.K. Prospective Diabetes Study of type 2 diabetes, islet cell antibodies (ICAs) and antibodies to glutamic acid decarboxylase (anti-GAD) were measured at diagnosis in 3,672 patients. The overall proportion with ICAs was 6%, and anti-GADs was 10%. These subjects clearly had type 1 diabetes or LADA by both phenotypic and genotypic features. The presence of auto antibodies correlated particularly with a younger age and phenotypic features consistent with type 1 diabetes (e.g., early age at diagnosis, lower BMI, and reduced beta-cell function). Overall, of patients requiring insulin by 6 years, 38% were anti-GAD+ at baseline compared with 5.3% of those not on insulin at 6 years. Antibodies to GAD indicate an underlying autoimmune process and have a high positive predictive value for type 1 diabetes and future insulin dependency in adults.     

Clinical, immunological, and genetic heterogeneity of diabetes in an Italian population-based cohort of lean newly diagnosed patients aged 30-54 years. Piedmont Study Group for Diabetes Epidemiology.

OBJECTIVE: In lean diabetic patients, the presentation of the disease does not allow one to easily distinguish between type 1 and type 2. Aims of this study were to describe clinical, immunological, and genetic features of lean newly diagnosed diabetic patients. RESEARCH DESIGN AND METHODS: A population-based cohort of 130 lean (BMI < 25 kg/m2) newly diagnosed patients, aged 30-54 years, was identified among residents of the province of Turin. Islet cell antibodies (ICAs), anti-GAD, fasting and glucagon-stimulated C-peptide values, and HLA DQA1-DQB1 susceptibility genotypes were assessed within 2 months of the diagnosis. RESULTS: A total of 45 (34.6%) and 29 (22.3%) patients were, respectively, ICA+ and anti-GAD+, with 15 (11.5%) having both antibodies. In 59 patients, ICAs and/or anti-GAD antibodies were detected, giving a high prevalence of autoimmunity (45.4%, 95% Cl 36.8-54.0); relative to patients without markers (n = 71), they were younger (40.8 +/- 7.5 vs. 45.0 +/- 6.5 years, P < 0.001) and showed lower values of fasting C-peptide (0.56 +/- 0.33 vs. 0.79 +/- 0.41 nmol/l, P < 0.001) and stimulated C-peptide (1.03 +/- 0.56 vs. 1.42 +/- 0.69 nmol/l, P < 0.001). The lowest stimulated C-peptide values were found in patients with both ICA and anti-GAD antibodies. Frequencies of adult-onset type 1 and type 2 diabetes were, respectively, 49.2 and 50.8%. Clinical and genetic features were not useful in the classification of patients. CONCLUSIONS: Almost 50% of lean young and middle-aged patients were ICA+ and/or anti-GAD+, suggesting a high prevalence of a slowly evolving form of type 1 diabetes. The evaluation at diagnosis of both beta-cell secretory capacity and markers of autoimmunity is recommended to provide a pathogenetic classification of the disease.     

Thyroid autoimmunity in children and adolescents with type 1 diabetes: a multicenter survey

OBJECTIVE: To investigate thyroid autoimmunity in a very large nationwide cohort of children and adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS: Data were analyzed from 17,749 patients with type 1 diabetes aged 0.1-20 years who were treated in 118 pediatric diabetes centers in Germany and Austria. Antibodies to thyroglobulin (anti-TG) and thyroperoxidase (anti-TPO) were measured and documented at least once in 7,097 patients. A total of 49.5% of these patients were boys, the mean age was 12.4 years (range 0.3-20.0 years), and the mean duration of diabetes was 4.5 years (range 0.0-19.5 years). A titer exceeding 100 units/ml or 1:100 was considered significantly elevated. RESULTS: In 1,530 patients, thyroid antibody levels were elevated on at least one occasion, whereas 5,567 were antibody-negative during the observation period. Patients with thyroid antibodies were significantly older (P < 0.001), had a longer duration of diabetes (P < 0.001), and developed diabetes later in life (P < 0.001) than those without antibodies. A total of 63% of patients with positive antibodies were girls, compared with 45% of patients without antibodies (P < 0.001). The prevalence of significant thyroid antibody titers increased with increasing age; the highest prevalence was in the 15- to 20-year age group (anti-TPO: 16.9%, P < 0.001; anti-TG: 12.8%, P < 0.001). Thyroid-stimulating hormone (TSH) levels were higher in patients with thyroid autoimmunity (3.34 microU/ml, range 0.0-615.0 microU/ml) than in control subjects (1.84 microU/ml, range 0.0-149.0 microU/ml) (P < 0.001). Even higher TSH levels were observed in patients with both anti-TPO and anti-TG (4.55 microU/ml, range 0.0-197.0 microU/ml). CONCLUSIONS: Thyroid autoimmunity seems to be particularly common in girls with diabetes during the second decade of life and may be associated with elevated TSH levels, indicating subclinical hypothyroidism.     

A proposal of three distinct subtypes of type 1 diabetes mellitus based on clinical and pathological evidence

To better understand the pathogenesis of type 1 diabetes, our group performed a pathological examination on the pancreas tissue of recent-onset type 1 diabetics and analysed their clinical characteristics. These studies led us to speculate that there are three distinct subtypes of type 1 diabetes mellitus: autoimmune, nonautoimmune fulminant and nonautoimmune nonfulminant (or nonautoimmune chronic). The autoimmune type 1 diabetes mellitus comprises about 60% of the patients and is characterized by insulitis and over-expression of class I MHC molecules in the islet cells, a high prevalence of diabetes-related autoantibodies, and a progressive loss of beta-cell function after the onset of diabetes. The nonautoimmune nonfulminant type 1 diabetes mellitus includes about 30% of the patients, shows neither insulitis nor over-expression of class I MHC antigen in the islet cells, and has a low prevalence of diabetes-related autoantibodies and a relatively slow progression of beta-cell loss after the onset of diabetes. The nonautoimmune fulminant type 1 diabetes comprises about 10% of patients and shows neither insulitis nor over-expression of class I MHC molecules, but is characterized by lymphocytic infiltration in the exocrine pancreatic tissue, elevated serum pancreatic enzyme levels, absence of diabetes-related autoantibodies and a remarkably aggressive course of disease. The appropriate classification of type 1 diabetes would increase our understanding of the pathogenesis of the disease and would allow to develop therapeutic means based on this understanding.     

Thyroid involvement in patients with overt HCV-related mixed cryoglobulinaemia

BACKGROUND: Mixed cryoglobulinaemia (MC), a systemic vasculitis associated with hepatitis C virus (HCV) infection in >90% of cases, is frequently complicated by multiple organ involvement. The prevalence of thyroid disorders in MC has not yet been studied. AIM: To investigate the prevalence and clinical features of thyroid involvement in patients with HCV-associated MC (HCV + MC). DESIGN: Case-control study. METHODS: HCV + MC patients (n = 93, 17 men and 76 women, mean +/- SD age 63 +/- 10 years, mean disease duration 14 +/- 7 years) consecutively referred to the Rheumatology Unit were matched by sex and age (+/- 2 years) to (i) 93 patients with chronic C hepatitis (CH) without MC and (ii) 93 healthy (HCV-negative) controls from the local population. Measurements included prevalence of hypo- or hyperthyroidism, thyroid autoantibodies, thyroid nodules and thyroid cancer. RESULTS: By McNemar's chi(2) test, the following thyroid abnormalities were significantly more frequent in HCV + MC patients than in HCV-negative controls: serum anti-thyroperoxidase autoantibody (AbTPO) (28% vs. 9%, p = 0.001); serum AbTPO and/or anti-thyroglobulin autoantibody (31% vs. 12%, p = 0.004); subclinical hypothyroidism (11% vs. 2%, p = 0.038); thyroid autoimmunity (35% vs. 16%, p = 0.006). Serum AbTPO were also significantly more frequent in HCV + MC patients than in CH controls (28% vs. 14%, p = 0.035). DISCUSSION: The prevalence of thyroid disorders is increased in patients with HCV-related mixed cryoglobulinaemia. We suggest careful monitoring of thyroid function in these patients.