Pancreatic autoantibodies in Italian patients with newly diagnosed type 1 diabetes mellitus over the age of 20 years

Novel Flow Cytometric Immunoassay for Detection of Proinsulin Autoantibodies in Diabetes Mellitus Employing a Recombinant Autoantigen Expressed in E. coli

Introduction

Insulin and proinsulin autoantibodies (IAA/PAA) are usually the first markers to appear in patients with type 1 Diabetes Mellitus (T1DM) and their prevalence ranges from 10 to 60% in the child-adolescent population. The reference method for IAA/PAA detection is the Radioligand Binding Assay (RBA), a highly specific and sensitive technique, but expensive and polluting. The aim of this work was to develop a novel flow cytometric microsphere-based immunoassay (FloCMIA) for PAA detection, employing recombinant human proinsulin (PI), as an alternative method to RBA, less expensive and harmful to the environment.

Materials and Methods

Human PI was expressed as Thioredoxin fusion protein (TrxPI) in E. coli and a fraction was biotinylated. A double paratope model was used in which samples were incubated with TrxPI-biotin and microspheres adsorbed with TrxPI. The immune complexes were revealed using Streptavidin-Phycoerythrin. The geometric mean of the signals was analyzed, and the results were expressed as Standard Deviation scores (SDs). Sera from 100 normal human control and from 111 type 1 diabetic patients were evaluated by FloCMIA. To correlate the novel assay with RBA, 51 diabetic patients were selected, spanning a wide range of PAA reactivity by RBA.

Results

The study of ROC curves allowed choosing a cut-off value of 3.0 SDs and the AUC was 0.705, indicating that FloCMIA has fair ability to distinguish between samples from each group. A prevalence of 50% for PAA was obtained in the population of diabetic patients studied. The specificity was 96% and the analytical sensitivity (percentage of patients RBA positive, also positive by FloCMIA) was 69%. There was a substantial agreement between methods (kappa statistic=0.700).

Conclusions

A novel immunoassay based on flow cytometry that uses easy-to produce recombinant PI was developed. This assay constitutes an innovative and cost-effective alternative to RBA for the determination of PAA in patients' sera. The method developed here, presents good performance and a wide dynamic range together with a small required sample volume. Furthermore, these results make it possible to develop multiplex immunoassays that allow the combined detection of autoantibodies present in T1DM and other related autoimmune diseases.

Adult-onset type 1 diabetic patients with less severe clinical manifestation have less risk DR-DQ genotypes than childhood-onset patients

BACKGROUND

The aim of this study was to investigate differences in clinical features and HLA genotypes between adult-onset and childhood-onset patients with type 1 diabetes in a Chinese population.

MATERIALS AND METHODS

This study enrolled 716 Han Chinese patients with type 1 diabetes from Guangdong (258 childhood-onset and 458 adult-onset) to compare their clinical features. Of them 214 patients with classical type 1 diabetes (100 childhood-onset and 114 adult-onset) were selected for HLA DR and DQ genotyping by next-generation sequencing.

RESULTS

Adult-onset patients were characterized by longer duration of symptoms before diagnosis, lower frequency of DKA at disease onset, less frequent autoantibody positivity, higher serum C-peptide concentrations, and better glycemic control. These findings were replicated in the restricted cohort of 214 patients with classical type 1 diabetes. Compared with childhood-onset patients, adult-onset patients had a lower frequency of the DR9 haplotype, as well as lower frequency of high-risk DR3/DR4 and DR3/DR9 genotypes, but higher frequency of DR3/DR3 genotype and DR3/X, DR4/X or DR9/X (X, non-risk) genotypes.

CONCLUSIONS

Adult-onset type 1 diabetic patients with susceptible haplotypes (DR3, DR4 or DR9) were more likely to carry protective DR-DQ haplotypes than childhood-onset patients, which suggested the association between less risk DR-DQ genotypes and the less severe clinical manifestation in adult-onset patients.

Prevalence of β-cell antibodies and associated autoimmune diseases in children and adolescents with type 1 diabetes (T1DM) versus type 2 diabetes (T2DM) in Qatar

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is an autoimmune disease with the development of abnormal immune responses to specific β-cell autoantigens in addition to other organ-specific autoimmunity. The most frequent associated disorders are thyroid dysfunctions and celiac disease. There are limited studies in the current literature on the prevalence of associated autoimmunity, especially multiple, in children and adolescents with T1DM and Type 2 diabetes mellitus (T2DM).

OBJECTIVES

The aim of the present study was to determine the prevalence of autoantibodies and thyroid dysfunctions in a cohort of children and adolescents (aged 0.5-16 years) with T1DM living in Qatar.

RESEARCH DESIGN AND METHODS

The records of all children and adolescents attending the Pediatric Diabetes Center of Hamad Medical Center, for the past 5 years (from January 2012 to December 2016), were reviewed and all clinical and biochemical data, including β-cell autoimmunity [anti-glutamic acid decarboxylase (GAD) antibodies, anti-islet cell and anti-insulin antibodies (IAA)], thyroid function (Free thyroxine: FT4 and thyroid-stimulating hormone: TSH), anti-thyroid peroxidase antibodies (TPO) and anti-tissue transglutaminase (ATT) were collected at their first presentation (cross-sectional study). Data for patients with T1DM (n=431) and T2DM (n=59) were recorded analyzed and the prevalence calculated and compared with other studies.

RESULTS

The prevalence of anti-GAD antibodies was 75.5 % in T1DM and 29.3% in T2DM. Anti β-islet antibodies (Ab) were detected in 53.4% of T1DM and 29.4% of T2DM. Anti-insulin Ab were detected in 40.4% of T1DM and 58.3% of T2DM. The three antibodies together were detected in 18.4 % of T1DM and none of T2DM. At presentation, hypothyroidism (FT4 <11.5 pmol/L) was detected in 10.6% of T1DM and 10% of T2DM.  Subclinical hypothyroidism was diagnosed in 3.5% of T1DM and 8% of T2DM. High anti TPO was detected in 27.2% of T1DM and 34.6% of T2DM. High TPO with normal thyroid function were found in 22.7% of T1DM and 23.1% of T2DM. ATT IgA was high in 5% of T1DM and 8.7% of T2DM whereas ATT IgG was high in 4.4 % of T1DM and not detected in any patient with T2DM. Mucosal biopsy proved celiac disease in 9 out of 12 patients (75%) with positive ATT IgA and IgG antibodies.

CONCLUSIONS

Qatar has a relatively high incidence of T1DM compared to incidences reported worldwide. The incidence increased over the period 2012-2015.  We report a high prevalence of associated autoimmune abnormalities in our patients with T1DM and T2DM. These data strengthen the argument for routine screening of all children and adolescents with T1DM and T2DM for other autoimmune disorders, particularly the thyroid gland.

Could ZnT8 antibodies replace ICA, GAD, IA2 and insulin antibodies in the diagnosis of type 1 diabetes?

BACKGROUND

The zinc transporter 8 (ZnT8) is an islet β-cell secretory granule membrane protein coded by the SLC30A8 gene, identified as a novel autoantigen in human type 1 diabetes (T1D). As no data of ZnT8ab in Algerian patients have been reported, we aim to evaluate the prevalence of ZnT8ab in young Algerians with T1D and determine whether ZnT8ab could be a better diagnostic tool to replace the other conventional autoantibodies detected in patients with type 1 diabetes. For this purpose, we evaluated the prevalence of islets cells antibodies (ICA), glutamic acid decarboxylase (GAD), islet antigen type 2 (IA2), insulin (IA) autoantibodies (ab) and for the first time in Algeria, the zinc transporter 8 (ZnT8) in young Algerian patients with type 1 diabetes.

PATIENTS AND METHODS

In our cross-sectional study, 160 patients between 1 and 35 years old, diagnosed with type 1 diabetes were enrolled. ICAab was analyzed by indirect immunofluorescence (IIF), GADab, IA2ab, IAab and ZnT8ab were analyzed by ELISA, fasting blood glucose was performed by enzymatic method (glucose-oxidase) and HbA1c by turbid metric method.

RESULTS

Our cohort was composed with 74 males and 86 females (OR=1.16); the mean of age was 14.09 [1-35] years old and the median diabetes duration was 4.10 [1-18] years. Our cohort had a mean of HbA1c of 9.22 [5.40-15]%, the mean of birth weight was 3360.52 [2200-4800]g; the mean of BMI was 19.30 [16.04-22.46]kg/m². Out of 160 patients, 44 (27.5%) were under mother breastfeeding and 116/160 (72.5%) were under artificial feeding. One antibody, at least, was found in 94.38% and the ZnT8ab was significantly more positive in females (70.3%) than in males (10.7%) (***P=8.033×10^-15). The concentration of ZnT8ab was higher in females than in males (females=122.25UI/mL versus males=51.38UI/mL; *P=0.03); ICAab, GADab and ZnT8ab were more present in patients with consanguineous parents (***P=0.0002, *P=0.019 and *P=0.03; respectively) CONCLUSION: Our study on ZnT8ab in T1D is the first in the Maghreb region and we observed a prevalence of 46.25%. The positivity of ZnT8ab enabled us to classify in T1DA 50% of diabetics with obvious T1D phenotype and negative routine autoantibodies, thus ZnT8ab is a good tool for differential diagnosis of type 1 diabetes. According to our results, a simultaneous analysis for ZnT8 and IA2 autoantibodies can be a better and efficient diagnosis of type 1A diabetes from the beginning of the disease.

Autoimmune polyendocrine syndrome 3 onset with severe ketoacidosis in a 74-year-old woman

Type 1 diabetes mellitus (T1D), autoimmune thyroid disease, and autoimmune gastritis often occur together forming the so-called autoimmune polyendocrine syndrome type 3 (APS3). We here report a clinical case of a 74-year-old woman who presented for the first time with severe hyperglycemia and ketoacidosis diagnosed as T1D. Further clinical investigations revealed concomitant severe hypothyroidism with autoimmune thyroid disease and severe cobalamin deficiency due to chronic atrophic gastritis. The diagnosis of type 1 diabetes mellitus was confirmed by the detection of autoantibodies against glutamic acid decarboxylase 65, islet cell antibodies, and anti-insulin autoantibodies. Anti-thyroperoxidase, anti-thyroglobulin, and anti-gastric parietal cell antibodies were also clearly positive. The case emphasized that new onset diabetic ketoacidosis, hypothyroidism, and cobalamin deficiency may simultaneously occur, and one disease can mask the features of the other, thereby making diagnosis difficult. It is noteworthy that an APS3 acute episode occurred in an asymptomatic elder woman for any autoimmune diseases.

The levels of circulating TRAIL at the onset of type 1 diabetes are markedly decreased in patients with ketoacidosis and with the highest insulin requirement

Experimental evidence in animal models suggests that TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF superfamily, might play an important role in type 1 diabetes (T1D). We have performed a retrospective study by analyzing the sera of a cohort of pediatric subjects (age ≤18 years; n = 507) consisting of (1) patients diagnosed with T1D (n = 387), (2) healthy individuals (n = 98, considered as controls), and (3) healthy autoantibody-positive subjects (n = 22). Patients with T1D exhibited significantly decreased levels of circulating TRAIL with respect to the control healthy subjects, as well as to the healthy autoantibody-positive subjects. Within the T1D group, no differences in the levels of circulating TRAIL were observed between patients with or without other concomitant autoimmune pathologies. Of note, the levels of TRAIL were significantly lower in the T1D patients analyzed at onset, although reduction in TRAIL levels persisted also in patients analyzed after disease onset (>1 year from diagnosis). In particular, T1D patients who exhibited ketoacidosis at onset showed significantly lower levels of circulating TRAIL with respect to patients without ketoacidosis at onset. Moreover, the levels of TRAIL at diagnosis correlated inversely with the insulin requirement up to 21 months of follow-up. This is the first study demonstrating that the levels of circulating TRAIL are significantly decreased in T1D, with the lowest levels of TRAIL being observed in patients with ketoacidosis at the onset and with the highest insulin requirement.

Comparison of the prevalence of islet autoantibodies according to age and disease duration in patients with type 1 diabetes mellitus

PURPOSE

This study investigated the prevalence of islet autoantibodies in children and adults with T1DM according to their age and the duration of disease.

METHODS

We measured the levels of islet autoantibodies, including antiglutamic acid decarboxylase antibody (anti-GAD Ab), and combined these with anthropometric measurements and laboratory tests of 137 patients newly diagnosed with T1DM during the last 20 years. The subjects were subdivided into four groups according to their age at the onset of the disease. We then compared the prevalence of islet autoantibodies in the different age groups with the duration of disease.

RESULTS

Among the 137 patients, 68.9% tested positive for islet autoantibodies (71.4% within 1 year; 67.7% after 1 year of the disease onset). Within 1 year of the onset of the disease, 66.3% of the patients were positive for the anti-GAD Ab, and 35.6% were positive for IAAs. The prevalence of islet autoantibodies was significantly higher in the prepubertal groups than in the postpubertal groups (80.0% vs. 58.3%). The rate of positive islet autoantibodies changed with the duration of disease, and it differed according to the type of autoantibody and the age of the patient.

CONCLUSION

The rates of positive islet autoantibodies were significantly higher in younger than in older patients at the time of the diagnosis of the disease. The positive rates were significantly changed 1 year after the onset of the disease in the preschool and the children groups. So these findings suggest that we need to diagnose type 1B diabetes distinguished T2DM in aldolescent group, carefully.

Clinical, subclinical and potential autoimmune diseases in an Italian population of children with coeliac disease

BACKGROUND Several studies have suggested a link between coeliac disease and other autoimmune diseases. AIM To compare the presence of autoimmune disease in children with coeliac disease and in controls. METHODS When coeliac disease was diagnosed, 267 children were evaluated for clinical autoimmune disease (with signs/symptoms), subclinical autoimmune disease (with autoantibodies and subclinical impairment of the target organ) or potential autoimmune disease (with autoantibodies only) and compared with 220 healthy controls. 170 coeliac disease patients were followed up for a mean 47 +/- 31 months, in complete remission on a gluten-free diet. Ninety-nine controls were followed up for 45 +/- 33 months. RESULTS When coeliac disease was diagnosed, 71 (27%) children had autoimmune disease vs. 1% among the controls (P < 0.001): 31 had clinical autoimmune disease and 40 had subclinical or potential autoimmune disease. During the follow-up, the clinical autoimmune disease cases slightly decreased from 12% to 11%, while the potential autoimmune disease cases increased from 14% to 21%. Of the 99 controls, none had any variation in their autoantibody profile. CONCLUSIONS Gluten-free diet does not modify the natural history of autoimmunity in patients with coeliac disease. However, gluten-free diet seems to produce a favourable effect on the previously present clinical autoimmune disease and to prevent the development of new clinical autoimmune disease, but does not affect the onset of potential autoimmunity, which tends to increase with time.