Genetic heterogeneity of autoimmune diabetes: age of presentation in adults is influenced by HLA DRB1 and DQB1 genotypes (UKPDS 43). UK Prospective Diabetes Study (UKPDS) Group

AIMS/HYPOTHESIS

Juvenile-onset, insulin-dependent diabetes is associated with islet cell antibodies and with specific "high-risk" HLA-DRB1 and HLA-DQB1 genotypes. Patients with Type II (non-insulin-dependent) diabetes mellitus can have islet-related antibodies, but the genotypic associations at different ages of onset have not been evaluated. Our aim was to determine (i) the prevalence of DRB1 and DQB1 genotypes in patients at diagnosis of Type II diabetes at different ages from 25 to 65 years compared with the general population, and (ii) whether the presence of islet cell antibodies (ICA) or glutamic acid decarboxylase antibodies (GADA) or both by age is associated with different DRB1 and DQB1 genotypes.

METHODS

The antibodies to islet cells and those to glutamic acid decarboxylase were measured in 1712 white Caucasian diabetic subjects at diagnosis of diabetes and they were genotyped for HLA DRB1*03 and DRB1*04 and the high-risk DRB1*04-DQB1* 0302 haplotype. To assess over-representation of high-risk alleles for Type I (insulin-dependent) diabetes mellitus, the prevalence of high-risk alleles in diabetic patients was expressed relative to the prevalence of low-risk alleles, non-DR3/non-DR4, that provided a reference denominator in both the diabetic patients and in 200 non-diabetic control subjects. The prevalence of ICA or GADA or both in patients with different HLA genotypes was assessed in those diagnosed in four age groups, 25-34 years, 35-44 years, 45-54 years and 55-65 years.

RESULTS

In Type II diabetic patients presenting at ages 25-34, 35-44 and 45-54 years, there was an increased prevalence of DR3/DR4 compared with the general population with approximately 6.5-fold, 2.9-fold, 2.1-fold over-representation, respectively (p < 0.0001, < 0.01, < 0.05) but this was not found in those aged 55-65 years old. In the group aged 25-34 years, 32 % of patients with ICA or GADA or both had DRB1*03/DRB1*04-DQB1*0302 compared with 10% in those aged 55-65 years and expected 3% prevalence. Conversely, only 14% of those aged 25-34 years with antibodies had non-DR3/non-DR4, compared with 35 % in those aged 55-65 years. There was thus pronounced age heterogeneity in DRB1 and DQB1 predisposition to Type II diabetes. The antibodies displaced DRB1 or DQB1 genotypes in the multivariate model for requiring insulin therapy by 6 years of follow-up.

CONCLUSION/HYPOTHESIS

The age of presentation of Type I diabetes in adulthood was in part dependent on the DRB1/DQB1 genotype. Islet cell antibodies and glutamic acid decarboxylase antibodies were strongly associated with DRB1*03/DRB1*04-DQB1*0302 in early adulthood but showed little relation with specific HLA genotypes after the age of 55 years.

HLA-DMB expression by thyrocytes: indication of the antigen-processing and possible presenting capability of thyroid cells

Expression of HLA class II molecules on thyrocytes is a characteristic feature of autoimmune thyroid disease and may lead the thyroid cells to present autoantigens to CD4+ T lymphocytes. Since HLA-DM is a critical molecule in class II-restricted antigen processing and presentation, we assessed the expression of HLA-DMB, -invariant chain (Ii), class II transactivator (CIITA) and DRA in an untransformed, pure thyrocyte strain HTV-59A. Here we report that both HLA-DMB mRNA and the protein are expressed in thyrocytes and that CIITA expression is enhanced by interferon-gamma (IFN-gamma) treatment and occurs before DMB, Ii and DRA up-regulation, suggesting CIITA expression is a requirement for antigen processing in thyrocytes. These results indicate that thyrocytes are capable of antigen processing and possibly antigen presentation to T cells.

IL-10 expression in thyroid glands: protective or harmful role against thyroid autoimmunity?

IL-10 is a cytokine which not only suppresses cellular immunity but also stimulates the humoral response. In certain animal models of autoimmunity, IL-10 exerts a protective effect against autodestruction. This study was to ascertain whether there could be a role for IL-10 in human autoimmune thyroid disease. Total RNA was extracted from snap-frozen thyroid blocks from surgical specimens. Five 'normal', five multinodular, six Graves and two Hashimoto thyroids (one euthyroid and one hypothyroid) were studied. Approximately 7 microg of total RNA from each gland were reverse transcribed with oligo-dT primers. Pre-plateau semiquantitative polymerase chain reaction (PCR) was performed with specific IL-10 primers. PCR products were run on a 1-5% agarose gel, blotted onto a N-hybond nylon membrane, hybridized with a specific internal probe labelled with gamma-32P-ATP and autoradiographed. Statistical analysis of densitometric values showed significantly higher IL-10 levels in the autoimmune than in the non-autoimmune glands. In situ hybridization and immunohistochemistry showed that the IL-10 message was located within the infiltrating lymphomononuclear cells. Histological analysis revealed that the autoimmune thyroids with the highest IL-10 levels were characterized by relevant degrees of B and T cell infiltration and also exhibited the greatest percentage of spontaneous HLA class II expression on thyrocytes. IL-10 and neutralizing anti-IL-10 antibodies were not able to regulate in vitro spontaneous or interferon-gamma (IFN-gamma)/phytohaemagglutinin (PHA)-induced HLA class II on thyrocytes. We conclude that in active autoimmune thyroiditis, in addition to the well documented production of Th1 cytokines, Th2-related lymphokines can be detected simultaneously. It can be envisaged that in this condition the role of IL-10 might be directed to the stimulation of B cell proliferation and antibody production rather than to the suppression of proinflammatory cytokine release.

Simultaneous onset of type 1 diabetes mellitus in identical infant twins with enterovirus infection

This report describes classical Type 1 insulin deficient diabetes mellitus (DM) arising in twins aged 14 months, both of whom had evidence of enterovirus infection. The diagnosis of Type 1 DM was made in the second twin within 12 days of the first. Enterovirus infection was detected in each twin at diagnosis by polymerase chain reaction (PCR). Both twins were negative for enterovirus by PCR 5 months following diagnosis, although both were then positive for islet cell antibodies. Sequencing of the amplicons produced by PCR suggested that the viruses from each twin were not the same but that they were both variants related to echovirus 6.

The "Sardinia-IDDM study": an attempt to unravel the cause of insulin-dependent diabetes mellitus in one of the countries with the highest incidence of the disease in the world

Sardinia and Finland have the highest incidence of IDDM in the world. Thus, both regions represent ideal observatories for investigating the environmental, genetic and immunological factors, which have led to this dramatic increase. We have concentrated our efforts in Sardinia. Among several projects, there is the mapping of the Island for hot and cold spots for overt IDDM. In order to map the Island for pre-IDDM, we have collected and bled around 10,000 school children (age 6-14 years) and we are now in the process to enroll around 30,000 newborn. We report here our initial results, which show that progression to IDDM is accompanied in both cohorts by the presence of a combination of ICA with either GAD and IA-2 antibodies or both. This approach should lead to design reliable models of IDDM prediction in the general population, which will benefit an early insulin treatment and, hopefully, an effective prevention of the disease.

Heterogeneity in the occurrence of a subset of autoantibodies to glutamic acid decarboxylase in autoimmune polyendocrine patients with islet cell antibodies

Glutamic acid decarboxylase-65 (GAD-65) is a major target for autoantibodies and autoreactive T cells in patients with insulin-dependent diabetes mellitus (IDDM). Autoantibodies to GAD are also found in patients with stiff man syndrome (SMS) or polyendocrine autoimmunity (PE). The epitope specificities of autoantibodies to GAD in IDDM and SMS have been well documented, but the locations of autoantibody epitopes of GAD in PE patients have not been mapped. Thus, the properties of anti-GAD antibodies in PE patients (with or without diabetes) were investigated. The ability of PE serum antibodies to inhibit the binding of the mouse monoclonal antibody, GAD-6, to native GAD in ELISA was determined. For PE patients without diabetes, levels of inhibition of GAD-6 binding ranged from 0% to almost 70% and were unrelated to the level of binding of serum antibodies to GAD (P = 0.351) or to the functional affinities of these antibodies. This suggests differences in the epitope specificities of anti-GAD antibodies in different patients. Levels of inhibition were also unrelated to clinical condition. SMS antibodies showed similar levels of inhibition of GAD-6 binding. Similar analysis was applied to PE patients with diabetes and levels of inhibition of GAD-6 binding to GAD were determined. These ranged from 0% to 80%, and levels of inhibition were similar in samples taken before or after diabetes onset. There was no significant difference between anti-GAD antibodies from PE patients with or without diabetes in the range of abilities to inhibit GAD-6 binding to GAD, although the highest levels of inhibition were given by sera from non-diabetic patients. This raises the possibility of differential expression of subsets of anti-GAD antibodies in progressive versus slow or non-progressive anti-islet autoimmune responses. Serum antibodies of PE and SMS patients did not inhibit the binding of antibodies specific for the extreme C-terminus of GAD, indicating that this is not the site of the epitopes for the patients' antibodies or for GAD-6.

The Sardinian IDDM study: 1. Epidemiology and geographical distribution of IDDM in Sardinia during 1989 to 1994

Analysis of the geographical variation of risk for a disease is a key issue in descriptive epidemiology and may provide useful suggestions for planning further studies to identify the underlying causes. We adopted a Bayesian approach to investigate the geographical distribution of insulin-dependent diabetes mellitus (IDDM) incidence rate across Sardinia. Data on incidence of IDDM in children aged under 15 years (619 IDDM cases) in Sardinia was obtained by the Sardinian Eurodiab ACE register. The overall completeness of ascertainment was: 91.3%. The average yearly standardized incidence rate for the years 1989-1994 was 33.24 per 100000 (95% C.I. 30.60, 35.88), which is the second highest in Europe after Finland. Sex and age-specific risks were higher in males than in females. Considering the variation of IDDM risk according to the age at diagnosis, the risk profile increased up to the 13th year of age for both sexes, being steeper in males. The degree of geographical variation in IDDM risk was small with a slight difference between the highest and the lowest standardized rate across the map. Indeed, even the municipalities at lowest risk in Sardinia showed a risk higher than most European countries. The Sardinian population is genetically atypical, characterized by genetic homogeneity and marked susceptibility to autoimmune diseases. Our finding of a small geographical variation within the island coupled with a marked temporal trend previously observed in data on military conscripts could be interpreted as evidence of a relatively recent environmental aetiological factor that was uniformly distributed across the island and had its effect in a genetically predisposed population.

Sardinia: a battlefield approach to type I diabetes epidemiology. Sardinia-IDDM Study Groups

Sardinia and Finland have the highest incidence of insulin-dependent diabetes mellitus (IDDM) in the world. Therefore, both regions represent ideal observatories for investigating the environmental, genetic and immunological factors which have led to this dramatic increase. We have concentrated our efforts on Sardinia. Among several projects, there is the mapping of the island for hot and cold spots for overt IDDM. In order to map the island for pre-IDDM, we have collected and bled around 10,000 school children (age 6-14 years) and we are now in the process of enrolling around 30,000 new-born babies. We report here our initial results, which show that progression to IDDM is accompanied in both cohorts by the presence of a combination of islet-cell antibodies with either glutamic acid decarboxylase or IA-2 antibodies or both. This approach should lead to the design of reliable models of IDDM prediction in the general population, which will benefit an early insulin treatment and, hopefully, an effective prevention of the disease.

Prediction of IDDM in the general population: strategies based on combinations of autoantibody markers

Strategies for assessing risk of progression to IDDM, based on single and combined autoantibody measurement, were evaluated in 2,855 schoolchildren (median age 11.4 years) and 256 children with newly diagnosed IDDM (median age 10.2 years), recruited to a population-based study in the Oxford region. In 256 children with IDDM, levels of antibodies > or =97.5th centile of the schoolchild population were found in 225 (88%) for islet cell antibodies (ICAs), in 190 (74%) for antibodies to GAD, in 193 (75%) for antibodies to protein tyrosine phosphatase IA-2 (IA-2), and in 177 (69%) for autoantibodies to insulin (IAAs). Estimates of risk of progression to IDDM within 10 years, derived by comparing the distribution of antibody markers in the two populations (schoolchildren and children with IDDM), were 6.7% (ICAs), 6.6% (GAD antibodies), 5.6% (IA-2 antibodies), and 4.8% (IAAs) for schoolchildren with levels above the 97.5th centile, increasing to 20, 23, 24, and 11%, respectively, for antibody levels >99.5th centile. Most children with IDDM had multiple antibody markers, and 89% of those diagnosed over age 10 years had > or =2 antibodies above the 97.5th centile, as compared against 0.7% of schoolchildren, in whom this combination gave a 27% 10-year estimated risk of IDDM. Risk increased but sensitivity fell as combined antibody thresholds were raised, or the number of antibodies above the threshold was increased. Strategies based on detection of > or =2 antibodies with primary testing for GAD and IA-2 antibodies and second line testing for ICAs and/or IAAs were evaluated. Detection of at least two markers selected from GAD antibodies > or =97.5th centile and/or IA-2 antibodies > or =99.5th centile and/or ICAs > or =97.5th centile identified 0.25% of schoolchildren and 83% of children with newly diagnosed IDDM, with an estimated risk of 71% (95% CI 57-91). Although confirmation from prospective studies is still needed, this analysis suggests that antibody combinations can predict diabetes in the general population.

UKPDS 25: autoantibodies to islet-cell cytoplasm and glutamic acid decarboxylase for prediction of insulin requirement in type 2 diabetes. UK Prospective Diabetes Study Group

BACKGROUND

Autoantibodies to islet-cell cytoplasm (ICA) and glutamic acid decarboxylase (GADA) can occur in apparently typical, non-insulin dependent diabetes mellitus (type 2). We investigated whether the presence of either or both antibodies characterises a subtype of diabetes and provides better prediction of requirement for insulin therapy by 6 years' follow-up than clinical variables.

METHODS

We measured ICA and GADA at diagnosis of diabetes in a representative population of 3672 white patients with type 2 diabetes, aged between 25 and 65 years. The phenotype was assessed by age of onset, body-mass index, percentage haemoglobin A1c (HbA1c), and islet beta-cell function. We investigated the need for insulin therapy among 1538 patients not assigned insulin and followed up for 6 years from diagnosis.

FINDINGS

The proportion of patients with ICA and GADA decreased with increasing age at diagnosis (from 33 [21%] of 157 patients aged 25-34 [corrected] to 66 [4%] of 1769 aged 55-65 for ICA; from 53 [34%] to 122 [7%] for GADA). Among patients younger than 35 at diagnosis, those with ICA or GADA had lower body-mass index than those without (mean 24.9 [SD 6.0] vs 31.7 [7.3] kg/m2; p < 0.0001 and had higher percentage of HbA1c (9.7 vs 8.7%, p < 0.05). 94% of patients with ICA and 84% of those with GADA required insulin therapy by 6 years, compared with 14% of those without the antibodies (p < 0.0001). Among patients older than 55 at diagnosis, the difference between those with and without antibodies in body-mass index was smaller (27.2 [5.4] vs 28.6 [4.8] kg/m2, p < 0.001); 44% of those with ICA, 34% of those with GADA, and 5% with neither antibody required insulin therapy by 6 years (p < 0.0001). Among patients older than 45 years, body-mass index and HbA1c provided little predictive information for insulin requirement, whereas the positive predictive values of GADA (> or = 60 U/L) alone, or both GADA (> or = 20 U/L) and ICA (> 5 U/L), for insulin therapy were 52% and 68%.

INTERPRETATION

Among young adults with type 2 diabetes, the phenotype of those with ICA or GADA antibodies was similar to that of classic juvenile-onset insulin-dependent diabetes, and either phenotype or antibodies predicted insulin requirement. In older adults, the phenotype was closer to that of patients without antibodies and only the presence of antibodies predicted an increased likelihood of insulin requirement.

Analysis of apoptosis in relation to tissue destruction associated with Hashimoto's autoimmune thyroiditis

The level of apoptosis has been investigated in thyroid tissue from eight patients with Graves's disease, one with Hashitoxicosis, three with Hashimoto's thyroiditis, and five patients with multinodular goitre, using flow cytometry and an in situ immunofluorescence technique. Cryostat sections have also been studied for Bcl-2 and APO-1/Fas expression in the thyrocytes and infiltrating lymphocytes, to determine their susceptibility to apoptosis. An increased level of apoptosis was detected in Hashimoto's glands. This was associated with decreased Bcl-2 staining and a patchy APO-1/Fas reactivity on thyrocytes. In addition, APO-1/Fas expression was noted within the germinal centres of lymphoid follicles. It is suggested that the dysregulation of apoptosis-related genes could be an important factor in the progression of destructive thyroid autoimmune disease.

Identification of a novel type 1 diabetes-specific epitope by screening phage libraries with sera from pre-diabetic patients

We used random peptide libraries displayed on phage to search for ligands to insulin dependent diabetes mellitus-related antibodies and were able to identify several candidate disease-related peptides. One of them, clone 92, showed a significant difference in the frequency of reactivity with the sera of patients and normal controls. Human immunoglobulins immunopurified on phage 92 specifically stained the islets on human pancreatic sections. When injected into rabbits, the selected peptide elicited antibodies that also stained human and rat pancreatic sections, with a pattern similar to that observed with immunoglobulins purified from the sera of patients. No reactivity was observed in other tissues. Our results indicate that the peptide identified in this work mimics a novel, diabetes-related self-antigen.

The genetic and bacteriological aspects of Peyronie's disease

PURPOSE

Peyronie's disease has been associated with HLA tissue types, including HLA-A1, DR3, DQw2 and HLA-B7 cross-reactive group antigens which include HLA-B27. This association was tested as was the process of molecular mimicry where the host HLA surface antigen cross-reacts with a microorganism.

MATERIALS AND METHODS

HLA tissue typing was performed on 51 white patients with Peyronie's disease, of whom 15 also had Dupuytren's contracture of the hand. Fecal, urine and urethral samples were taken from patients with Peyronie's disease who had proved penile inflammation on biopsy. The samples were cultured for species of Campylobacter, Shigella, Salmonella, Yersinia, Chlamydia and gonococcus, all known to cross-react with the HLA-B27 surface antigen. Antibodies to Klebsiella species, Proteus species and Escherichia coli were also assessed in the sera of 65 patients with Peyronie's disease.

RESULTS

A significant association between Peyronie's disease and HLA-B27 was found (p = 0.02). The remaining antigens of the HLA-B7 group were not significantly associated with the disease individually (HLA-B7 p > 0.2, HLA-B22 p > 0.6, HLA-B40 p > 0.7) or as a group (p = 0.69). The previously found associations did not reach significance in this study (HLA-A1 p > 0.5, HLA-B8 p > 0.2, HLA-Cw7 p = 0.1, HLA-DR3 p > 0.4, HLA-DQ2 p > 0.4). Cultures for all enteric and urethral organisms were negative, and patients with Peyronie's disease did not have elevated serum titers of anti Klebsiella, anti Proteus or anti E. coli antibodies.

CONCLUSIONS

Although there is an association between Peyronie's disease and HLA-B27, molecular mimicry does not occur with the organisms tested, and an infectious agent has not been found in this study.

The effect of TNF*B gene polymorphism on TNF-alpha and -beta secretion levels in patients with insulin-dependent diabetes mellitus and healthy controls

TNF-alpha and -beta have been implicated in the development of HLA-associated autoimmune diseases. It has been suggested that inter-individual differences in the secretion levels of these cytokines may contribute to the predisposition of certain individuals to the development of diseases such as insulin-dependent diabetes mellitus (IDDM). We have investigated whether a diallelic TNF*B polymorphism detected using the enzyme Ncol influences the TNF-alpha and/or -beta secretory capacity of peripheral blood mononuclear cells (PBMC) from PHA stimulated healthy individuals and IDDM patients. We have shown that the level of TNF-beta secreted correlates with the TNF*B genotype in healthy individuals: those with the TNF B*2 allele secreted significantly higher levels of TNF-beta (P = 0.025) than those with the TNF*B1 allele. In IDDM patients, the reverse situation was observed, with those patients with the TNF*B1 allele secreting higher levels of TNF-beta than those with the TNF*B2 allele. No correlation was found between TNF-alpha levels and TNF*B genotype. Furthermore, when IDDM patients and controls were matched for TNF*B genotype, the IDDM patients with the TNF*B2 allele secreted significantly lower levels of TNF-beta than controls with this allele. On analysis of IDDM-susceptible extended HLA haplotypes in the homozygous groups, 4/7 IDDM patients with the TNF*B2 allele were Bw62-DR4 compared with 0/16 matched controls. Thus, the extended haplotype Bw62-DR4-TNF*B2/2 rather than IDDM per se is almost certainly responsible for the depressed TNF-beta secretion found in the IDDM-TNF*B2 homozygous cohort.

Islet cell surface antibodies are more common in patients and relatives in areas and during seasons with high incidence of insulin-dependent diabetes mellitus

Although existence of islet cell antibodies (ICA) is regarded as secondary to beta cell death, islet cell surface antibodies (ICSA) might play a role in the disease process. We have collected information from nine European clinics to determine whether ICSA are more common in diabetic children or their relatives in geographical areas or time periods of high incidence of insulin-dependent diabetes mellitus (IDDM). In Finland and Sweden ("North group") with a high incidence of IDDM during childhood, 36% of the patients were positive or weakly positive for ICSA at diagnosis compared with 24% in France (p = 0.1), 11% in Berlin-Vienna (p < 0.01), and 14% in Italy (p < 0.01). This difference was seen in all age groups but was most pronounced in the youngest (0-4 y). This geographical difference was also seen among family members of whom 46% were positive or weakly positive in the North group, 25% in France (p < 0.001), 21% in Berlin-Vienna (p < 0.001), and 16% in Italy (p < 0.001). Of several analyzed antibodies (ICA, gastric parietal cell, thyroglobulin, and thyroid microsomal), only ICSA showed simultaneous positivity in all family members (r = 0.32, p < 0.01). ICSA were most common in family members of patients with short (< 8 d) duration of symptoms (p < 0.05) and showed a similar seasonality, both in patients and relatives, as the incidence of IDDM. We conclude that the geographical difference in incidence of childhood IDDM in Europe may be associated to similar geographical differences in occurrence of ICSA both in newly diagnosed diabetic children and in their relatives. Simultaneous existence of ICSA in both patients and family members and a similar seasonality for ICSA and incidence of IDDM suggest that ICSA may reflect an ongoing disease process.

The immunological features of Peyronie's disease

PURPOSE

We investigated the immunological features and possible autoimmune basis of Peyronie's disease.

MATERIALS AND METHODS

The sera of 100 patients with Peyronie's disease were tested for circulating autoantibodies, including anti-penis antibodies, by indirect immunofluorescence. Antibody deposition and the immunological activity in Peyronie's plaque tissue from patients with early and long-standing disease were also assessed.

RESULTS

Circulating anti-penis antibodies were not found in any patient although antinuclear antibodies were present in 24%. Patients with early Peyronie's disease had IgM antibody deposition, marked T lymphocytic and macrocytic infiltration in the sub-tunical space, increased expression of adhesion molecules by endothelial cells and an increased human lymphocyte antigen class 2 expression by the cellular infiltrate, indicating cellular immune activation.

CONCLUSIONS

These results show that some of the features of autoimmunity, in particular the cell mediated response, are present in Peyronie's disease.

Organ-specific cardiac autoantibodies in dilated cardiomyopathy--an update

Autoimmune disease is characterized by the presence of organ- and disease-specific autoantibodies in patients and first degree relatives; antibody detection may precede disease onset by several years. We investigated potential involvement of organ-specific autoimmunity in dilated cardiomyopathy (DCM). Using indirect immunofluorescence and absorption studies, organ- and disease-specific IgG cardiac antibodies were found in one-third of DCM patients. Antibody status at diagnosis was associated with better exercise capacity; at 1-year follow-up two-thirds of antibody-positive patients became negative. These findings suggest that antibodies are early markers; their absence in the majority of patients at diagnosis may relate to long-standing pre-clinical DCM. Antibody screening was performed in asymptomatic DCM relatives, 177 from 33 families with > 1 affected individual (familial DCM) and 165 from 31 pedigrees with non-familial DCM. Antibodies were detected in 37 (58%) pedigrees and were more common among relatives than in normals (20% vs 3.5%, P = 0.0001). Antibody-positive relatives were younger, had larger left ventricular end-systolic dimension and reduced % fractional shortening compared to antibody-negative relatives. These findings provide evidence for autoimmunity in a subset (58%) including both familial and non-familial DCM; cardiac-specific antibodies may identify relatives at risk of developing DCM.