Inherited susceptibility to insulin-dependent diabetes is associated with HLA-DR1, while DR5 is protective

Epidemiologic Implication of the Association between Herpes Simplex Virus Infection and the Risk of Type 1 Diabetes Mellitus: A Nationwide Case-Control Study in Taiwan

Enterovirus infection is a known risk factor for type 1 diabetes (T1DM). Whether infection with other viruses induces T1DM remains undetermined. This study investigated the association between human herpesvirus (HHV) infection and the development of T1DM, using the data from Taiwan’s National Health Insurance Research Database. Patients with T1DM and age- and sex-matched controls were included. Subjects with HHV infection were subgrouped into those with histories of varicella-zoster virus, herpes simplex virus (HSV), Epstein-Barr virus, and human cytomegalovirus infections. The odds ratio of the risk of T1DM was calculated using a multivariable conditional logistic regression model. Atopic diseases, autoimmune thyroid diseases, and history of enterovirus infection served as adjusted comorbidities. Our findings suggested a significant association between HSV infection and the risk of T1DM (adjusted odds ratio: 1.21; 95% CI: 1.01–1.47, p = 0.048), while infection with other HHVs was not. The result of HSV infection remained significant when subjects were restricted to age ≤ 18 years (adjusted odds ratio: 1.35; 95% CI: 1.08–1.70, p = 0.010). We found a history of HSV infection might be an independent predictive risk factor for T1DM. This could be potentially helpful to the practice in public health.

Type 1 diabetes: current concepts in epidemiology, pathophysiology, clinical care, and research

Type 1 diabetes (T1D) is an autoimmune disease mediated by a combination of genetic and environmental triggers resulting in lymphocytic infiltration of pancreatic islets, destruction of beta cells, and lifelong dependency on exogenous insulin. Although T1D is prevalent (1 in 300) and its incidence is steadily increasing worldwide (3% per year), the exact gene-environment interactions precipitating the disease remain unknown. Living with T1D is challenging for patients, families, and caregivers. Because of the relative paucity of pediatric endocrinologists, general pediatricians and other subspecialists may occasionally be faced with the task of managing diabetes-related complaints. Herein, we provide a comprehensive review of the natural history, pathophysiology, and contemporary management of T1D. In addition, recent advances in T1D research are discussed.

Preservation of C-peptide secretion in subjects at high risk of developing type 1 diabetes mellitus--a new surrogate measure of non-progression?

Individuals at high risk of developing type 1 diabetes mellitus can be identified using immunologic, genetic, and metabolic parameters. In the Diabetes Prevention Trial-1 (DPT-1), annual intravenous infusions of low doses of regular insulin, together with daily subcutaneous injection of a single low dose of Ultralente insulin at nighttime, failed to prevent or delay the onset of type 1 diabetes in high-risk non-diabetic relatives. In our study, we attempted to achieve beta-cell rest by administering higher doses of neutral protamine Hagedorn (NPH) insulin twice daily to high-risk non-diabetic subjects in an effort to prevent or delay the onset of the disease. The maximum tolerable dose was given with the dose reduced for any hypoglycemia (mean dose 0.33 +/- 0.15; range 0.09-0.66 units/kg/d). We treated 26 subjects who were confirmed to have islet cell antibodies (ICAs) and a low first-phase insulin response (FPIR) to intravenous glucose. Fourteen had normal glucose tolerance and 12 impaired glucose tolerance (IGT). The median duration of follow-up was 5.5 yr. Diabetes occurred in 10 of 12 subjects with IGT and five of 14 subjects with normal glucose tolerance. The cumulative incidence of diabetes was the same as with that seen in a matched, observation group (subjects followed prospectively as part of the University of Florida natural history studies) (age, sex, ICA, insulin autoantibodies, duration of ICA prior to enrollment, FPIR, and glucose intolerance; p = 0.39), as was the rate of progression (p = 0.79). There was a higher rate of progression to diabetes in the group with abnormal glucose tolerance at baseline than in those with normal baseline glucose tolerance (p = 0.003). Interestingly, in non-progressors, as opposed to progressors, there was no fall in C-peptide (peak and area under the curve) production regardless of the type of tolerance testing (mixed meal, oral or intravenous) over time (p < 0.001). In this study, in the dose and regimen of NPH insulin used, insulin did not delay or prevent the development of type 1 diabetes. However, preservation of C-peptide production in the prediabetic period appears to indicate non-progression to clinical disease and may serve as a new surrogate for determining response to preventative efforts.

[Biological differences on onset among type 1A diabetics in relation to HLA-DQ genetic markers]

BACKGROUND AND OBJECTIVE

The hypothesis that diabetes mellitus presentation partially depends on the genetic characteristics of the patient has been proposed. Up to date this kind of studies have been made by serology, so there are no data about the role played by DQ haplotypes in the presentation and clinical importance of DM1. This fact is analysed in the present study.

PATIENTS AND METHOD

We studied DQ haplotypes (molecular biology) in 86 patients affected by DM1. Their relationship with several parameters found on illness debut, such as age, sex, C peptid and clinical importance are analysed.

RESULTS

89% of the patients showed a DQ that increases the risk of diabetes. Average age on onset was 16 years and the median age 9 years. No differences in relation to sex were observed. DQA1*0501, 0301/DQB1*0201, 0302 heterocygotes show an earlier onset (9 years, opposite to 17 in the rest) and the youngest (smaller than 16 years) they have to the onset a smaller pancreatic reservation (peptid C of 0.37 ng/dl in front of 1.4 of those bigger than this age).

CONCLUSIONS

DQA1*0501, 0301/DQB1*0201 heterocygocity increases the probability of an earlier and more aggressive debut of the illness, being related this characteristic younger debut to a smaller pancreatic reservation.

HLA-DR3 and DR4 and their relation to the incidence and progression of diabetic retinopathy

PURPOSE

Cross-sectional data from the Wisconsin Epidemiologic Study of Diabetic Retinopathy indicated that patients with HLA-DR4, but not DR3, were more likely to have prevalent proliferative retinopathy than those without both antigens. We describe the relation of HLA-DR3 and DR4 antigens to the 14-year incidence and progression of diabetic retinopathy and macular edema in this cohort.

DESIGN

A population-based cohort study.

PARTICIPANTS

A probability sample of male and female patients receiving primary care for diabetes in 11 counties of southern Wisconsin.

METHODS

Participants were invited for a baseline examination in 1980 to 1982, with follow-up examinations at 4, 10, and 14 years later. At the 4-year examination, a random sample of participants (n = 428) diagnosed with diabetes before the age of 30 and taking insulin were selected for HLA-DR typing.

MAIN OUTCOME MEASURES

Fourteen-year incidence and progression of diabetic retinopathy and macular edema based on masked stereoscopic fundus photographic grading.

RESULTS

There was no relation between HLA-DR3 and DR4 status with the 14-year incidence and progression of diabetic retinopathy, progression to proliferative retinopathy, and incidence of macular edema. Patients with either HLA-DR3 or DR4 were less likely to progress to proliferative retinopathy compared with those who were negative for both, although these relations were not statistically significant. The associations did not vary after adjusting for hypertension status, baseline retinopathy, and glycosylated hemoglobin levels, or after stratifying by duration of diabetes (less than 10 years vs. 10 years or more) and age at diagnosis of diabetes (less than 15 years vs. 15 years or more). Furthermore, 10-year mortality and 14-year nephropathy rates did not differ by HLA-DR3 or DR4 status, suggesting that selective mortality did not explain the pattern of associations seen.

CONCLUSIONS

In contrast to the initial cross-sectional findings, these data suggest that HLA-DR3 or DR4 status is unrelated to 14-year incidence and progression of diabetic retinopathy. The discrepancy may be related to increasing homogeneity of retinopathy and diminishing power to detect small differences, but it may also reflect the uncertain and inconsistent effects of HLA-DR3 or DR4 on the development and progression of diabetic retinopathy.

Diabetes vaccines: a future to be realized

Immune-mediated (type 1) diabetes mellitus (IMD) is an autoimmune disease resulting from the chronic destruction of pancreatic islet cells by autoreactive T lymphocytes. Although there has been much advancement in diabetes management, targeting the precise etiology of the disease process has remained elusive. Recent progress in the understanding of the immunopathogenesis of IMD, however, has led to new intervention strategies, especially antigen-based therapies given as altered peptide ligands (APLs) or as vaccines. Instead of using immunosuppressive agents to suppress an already dysfunctional immune system, antigen specific vaccines or even non-antigen specific immunostimulants present a unique opportunity to boost regulatory function and thereby regain tolerance to self. We discuss here the pathogenesis of IMD as it relates to therapeutic possibilities, review various intervention strategies that have been successful in rodent models, and then present recent progress in human trials of diabetes intervention and prevention through vaccine prototypes.

Type I insulin-dependent diabetes mellitus: a model for autoimmune polygenic disorders

Insulin-dependent diabetes mellitus (IDD) affects between one in 250 and one in 500 Americans. The inheritance of IDD is non-Mendelian and polygenic. Genetic susceptibility predominantly results from specific alleles in the HLA complex and insulin gene region. Autoimmune destruction of pancreatic beta cells leads to profound insulinopenia (Atkinson and Maclaren, 1990). Without insulin treatment, fatal diabetic ketoacidosis results. Even with insulin treatment, after 10 to 20 years of IDD, devastating micro- and macrovascular complications lead to significant morbidity and premature mortality (Rosenbloom, 1983). In order to prevent this catastrophic disease and its consequences, we must understand the pathogenesis and immunogenetics of insulitis (the histologic lesion characteristic of IDD), whose ultimate expression is beta cell necrosis (Cudworth, 1978; Cahill and McDevitt, 1981; Eisenbarth, 1986). Current advances include recognition of new IDD-autoantigens (e.g., glutamic acid decarboxylase), susceptibility genes (e.g., HLA-DQB1*0201 and 0302), and the development of trials to prevent IDD through tolerization to IDD-autoantigens (e.g., insulin) (Maclaren, 1993; Winter et al., 1993). Unlocking the genetic mechanisms responsible for IDD can also reveal more general mechanisms involved in other organ-specific autoimmune diseases.

No primary association between the 308 polymorphism in the tumor necrosis factor alpha promoter region and insulin-dependent diabetes mellitus

Whereas TNF-alpha has been implicated in the pathogenesis of IDDM, its possible role as a primary genetic susceptibility factor has not been well investigated. In this study, we analyzed a biallelic polymorphism in the TNF-alpha promotor region in a large collection of IDDM patients and controls ascertained from two ethnic populations (U.S. Caucasians and Chinese in Taiwan). We report that the associations with TNF-alpha are due to linkage disequilibrium between TNF-alpha and the DR3-DQB1*0201 haplotype in both ethnic populations. Our analyses of extended haplotypes for the HLA region further substantiate the conclusion that no primary association exists between IDDM and the TNF-alpha promoter polymorphism.

Prevention of insulin-dependent diabetes-1995

Despite current treatment advances, insulin-dependent diabetes mellitus (IDD) is still associated with high morbidity and mortality, and with a huge financial burden both to the individual and society. Enhanced understanding of the natural history of the prediabetic period has made the disease predictable in both higher risk nondiabetic relatives and in the general population. Investigators around the world are now collaborating on three separate multicenter, randomized, controlled trials aimed at preventing the disease in at-risk individuals, engendering cautious optimism that the days are not too far away when IDD can safely be prevented.

Additive susceptibility to insulin-dependent diabetes conferred by HLA-DQB1 and insulin genes

Several genomic polymorphisms at the insulin (INS) gene and its flanking regions were analyzed in 197 unrelated Caucasian patients affected by insulin-dependent diabetes (IDDM) and 159 ethnically matched, normal controls ascertained from the South-Eastern United States. We found that the frequency of homozygotes for the common variant at the insulin gene was significantly increased in the diabetic population (RR = 2.0, p < 0.005). However, the polymorphisms in the 5' and 3' regions flanking the INS were not significantly associated with IDDM. These results suggest that the IDDM susceptibility locus on chromosome 11p is located within the region extending from the 5' VNTR to the 3' end of the INS gene. We determined the HLA-DQB1 genotypes by denaturing gradient gel electrophoresis (DGGE) and/or sequence-specific primers (SSP) techniques to assess the possible interactions between INS and HLA. DQB1*0302 had the strongest predisposing effect on IDDM susceptibility (RR = 9.3) and DQB1*0602 the strongest protective effect (RR = 0.02). However, a significant predisposing effect of DQB1*0201 could be demonstrated only after removal of the effects of DQB1*0302 and DQB1*0602. Analyses of the genotypes revealed that all genotypes containing 0602 were protective and that the heterozygous genotype 0201/0302 and homozygous genotype 0302/0302 confer the highest risk (RR = 20.9 and 12.9 respectively). However, heterozygous genotypes 0302/X (X excludes 0201, 0302 and 0602) have a significantly lower predisposing risk. Similarly, there is heterogeneity in risk between predisposing 0201/0201 homozygous individuals and protective 0201/X individuals. When subjects were stratified by HLA genotypes, the relative risks conferred by INS did not vary, thus suggesting that the susceptibility effects conferred by HLA and INS are additive rather than interactive.

HLA class II alleles and susceptibility and resistance to insulin dependent diabetes mellitus in Mexican-American families

The role of HLA class II alleles in genetic predisposition to insulin dependent diabetes mellitus (IDDM) was examined by PCR/oligonucleotide probe typing of 42 Mexican-American IDDM families derived from Hispanic Caucasians and Native Americans. All high risk haplotypes (HLA-DR3 and DR4) were of European origin while the most strongly protective haplotype (DRB1*1402) was Native American. Of the 16 DR-DQ DR4 haplotypes identified, only those bearing DQB1*0302 conferred risk; the DRB1 allele, however, also markedly influenced IDDM risk. The general pattern of neutral and protective haplotypes indicates that the presence of Asp-57 in the HLA-DQ beta chain does not confer IDDM protection per se and indicates that both DRB1 and DQB1 influence IDDM susceptibility as well as protection.

Profiling human leukocyte antigens in Vogt-Koyanagi-Harada syndrome

Human leukocyte antigen typing was performed in 32 consecutive Chinese patients with Vogt-Koyanagi-Harada syndrome and 52 unrelated healthy Chinese individuals. Results indicated that HLA-DR4 was identified in 24 of the 32 patients with Vogt-Koyanagi-Harada syndrome (75.0%), but only in 12 (23.1%) of the 52 control subjects (P = .0003; relative risk, 10.0). Human leukocyte antigen-DQw7, also correlated with the disease, was identified in 19 (59.4%) patients, and in 19 control subjects (36.5%; P = .0230). The two-haplotype association detection demonstrated that HLA-DR4 and HLA-DQw7 were related through linkage disequilibrium, suggesting that the disease was primarily associated with only one of the antigens. The comparison between HLA-DR4-positive and HLA-DR4-negative patients with Vogt-Koyanagi-Harada syndrome in regard to clinical manifestations has shown that the HLA-DR4-positive group had a lower visual acuity at the first visit than did the HLA-DR4-negative group. However, both groups responded well to corticosteroid treatment. No other significant correlations between HLA-DR4 positivity and ocular features, including complications or systemic features, were found. Therefore, we concluded that the presence of HLA-DR4 may represent susceptibility to Vogt-Koyanagi-Harada syndrome, but may not represent specific tissue involvement or determine the prognosis. A decreased frequency of HLA-DQw1 in the patient group was also noticed. Further studies showed a higher percentage of HLA-DQw1 in HLA-DR4-positive control subjects than in the HLA-DR4-positive patients (P = .0308), which indicated that HLA-DQw1 was negatively associated with the disease. This protective effect from HLA-DQw1 was also studied.

HLA and disease

Many human diseases are associated with HLA class I, class II and class III antigens. It appears that the class III antigen disease associations can be explained by a direct defect operating at the level of either the class III gene or its gene product. The mechanism underlying class I and class II antigen disease associations is at present unknown. In this review we have considered thirty diseases which have been ranked according to their relative risk as defined by the frequency of a given HLA antigen in patient and control populations. The chronic inflammatory disorder, ankylosing spondylitis and its association with HLA B27 has been used as a model to study the HLA linked diseases. We have suggested that the disease may be caused by the Gram-negative microorganism Klebsiella which has antigenic similarity to HLA B27. It is proposed that some antibodies made against Klebsiella bind to HLA B27, thereby acting as autoantibodies leading to the pathological sequelae of chronic inflammatory arthritis. This is the crosstolerance hypothesis or molecular mimicry model and it has been compared to the receptor model. It is further suggested that the crosstolerance hypothesis can be utilised as a general theory to explain the association of other diseases with the class I and class II antigens, and offer a possible explanation for the polymorphism of HLA.

Natural history of incidental hyperglycemia and glycosuria of childhood

We prospectively followed 29 children and adolescents over a 1- to 8-year period who were referred for evaluation of hyperglycemia (in the absence of diabetes) or glycosuria found on routine screening or during acute illness. On initial examination, four subjects had islet cell autoantibodies, 4 of 22 had an abnormal intravenous glucose tolerance test result, 6 of 22 had low first-phase insulin release on intravenous glucose tolerance testing, and 10 of 20 had impaired glucose tolerance on oral glucose tolerance testing. On follow-up, insulin-dependent diabetes had developed in two of the four subjects with islet cell autoantibodies. The other two subjects with islet cell antibodies have had persistently abnormal glucose tolerance on both oral and intravenous glucose tolerance testing and have low first-phase insulin responses. Diabetes has developed in none of 25 subjects without islet cell antibodies, although two have persistently abnormal glucose tolerance or insulinopenia. All five subjects with islet cell antibodies or human leukocyte antigen DR3/DR4 with initial impaired glucose tolerance have either acquired diabetes or have abnormal glucose tolerance. In contrast, only one of five subjects with initial impaired glucose tolerance but lacking these markers has persistent glucose intolerance. We conclude that in the absence of islet cell antibodies or human leukocyte antigen DR3/DR4 heterozygosity, incidental hyperglycemia or glycosuria is unlikely to be associated with progression or diabetes.

Immunosuppression with azathioprine and prednisone in recent-onset insulin-dependent diabetes mellitus

We randomly assigned 46 patients (mean age, 11.7 years; range, 4.5 to 32.8) with newly diagnosed insulin-dependent diabetes mellitus within two weeks of beginning insulin to receive either corticosteroids for 10 weeks plus daily azathioprine for one year or no immunosuppressive therapy. Half the 20 immunosuppressed patients completing the one-year trial had satisfactory metabolic outcomes (hemoglobin A1c less than 6.8 percent; stimulated peak C peptide greater than 0.5 nmol per liter; insulin dose less than 0.4 U per kilogram of body weight per day) as compared with only 15 percent of the controls. Three of 20 immunosuppressed patients, but no controls, were insulin independent at one year. Two of these continue to receive azathioprine without insulin after more than 27 months of follow-up. The response to immunosuppression correlated with older age, better initial metabolic status, and lymphopenia (less than 1800 lymphocytes per cubic millimeter) resulting from immunosuppression. The side effects of azathioprine included vomiting in one patient and mild hair loss in several others. Prednisone use resulted in a transient cushingoid appearance, weight gain, and hyperglycemia. The growth rate remained normal in all patients. We conclude that early immunosuppression with short-term use of corticosteroids plus daily azathioprine can improve metabolic control in some patients with insulin-dependent diabetes mellitus, but results from this unblinded study are preliminary and require further confirmation and long-term follow-up.