Importance of Zinc Transporter 8 Autoantibody in the Diagnosis of Type 1 Diabetes in Latin Americans

Prevalence, diagnostic utility, and clinical characteristics of ZnT8 antibody in children with type 1 diabetes in Northern Taiwan

BACKGROUND

The ZnT8 autoantibody is used to independently diagnose type 1 diabetes (T1D) and as a prediction factor in high-risk populations. This is the first report in Taiwan on the prevalence, diagnostic utility, and clinical characteristics of zinc transporter 8 autoantibody (ZnT8A) in children with T1D.

METHODS

We performed a retrospective analysis of 268 children (130 boys, 138 girls) newly diagnosed with T1D at three hospitals in North Taiwan from February 1994 to August 2021.

RESULTS

ZnT8A was detected in 117 patients (43.7 %). The combined diagnostic rate of the four antibodies, including glutamic acid decarboxylase autoantibody (GADA), islet antigen 2 autoantibody (IA2A), insulin autoantibody (IAA), and ZnT8A, can reach 86.19 % while that of the original three antibodies is 84.3 %. IA2A (64.9 %) showed the highest positive rate, followed by GADA (64.2 %), ZnT8A (43.7 %), and IAA (22.0 %). Of the 268 patients, five (1.9 %) were only ZnT8A+. All antibodies were positive in 19 (7.1 %) people, whereas 37 others (13.8 %) had all antibodies negative. ZnT8A has the strongest relationship with IA2A. 5 patients had ZnT8A positive only. 5/(37 + 5) (about 12 %) T1D patients were diagnosed by ZnT8A testing.

CONCLUSIONS

ZnT8A testing can diagnose up to 12 % more patients with T1D along with three other antibodies. Furthermore, since the ZnT8A titer decreased over time, it should be tested within six months of onset in Taiwanese patients with T1D.

Phage Display Technology in Biomarker Identification with Emphasis on Non-Cancerous Diseases

In recent years, phage display technology has become vital in clinical research. It helps create antibodies that can specifically bind to complex antigens, which is crucial for identifying biomarkers and improving diagnostics and treatments. However, existing reviews often overlook its importance in areas outside cancer research. This review aims to fill that gap by explaining the basics of phage display and its applications in detecting and treating various non-cancerous diseases. We focus especially on its role in degenerative diseases, inflammatory and autoimmune diseases, and chronic non-communicable diseases, showing how it is changing the way we diagnose and treat illnesses. By highlighting important discoveries and future possibilities, we hope to emphasize the significance of phage display in modern healthcare.

Exploration of Immune Targets for Type 1 Diabetes and Latent Autoimmune Disease Immunotherapy

Type 1 diabetes (T1D) is an autoimmune disease that destroys pancreatic beta cells, which produce insulin in the islets of Langerhans. The risk of developing T1D is influenced by environmental factors, genetics, and autoantibodies. Latent autoimmune diabetes in adults (LADA) is a type of T1D that is genetically and phenotypically distinct from classic T1D. This review summarizes the accumulated information on the risk factors for T1D and LADA, and immunotherapy trials that offer insights into potential future combined therapeutic interventions for both T1D and LADA to slow the rate of islet cell loss and preserve beta cell function. Future research should also focus on improving intervention doses, conducting more thorough examinations of intervention responders, and/or combining minimally effective single-target immunotherapies to slow the rate of islet cell loss and preserve beta cell function.

Islet Autoantibodies to Pancreatic Insulin-Producing Beta Cells in Adolescent and Adults with Type 1 Diabetes Mellitus: A Cross-Sectional Study

(1) Background: Type 1 diabetes mellitus (T1D) is a chronic autoimmune disease caused by the destruction of pancreatic insulin-producing beta cells. T1D is one of the most common endocrine and metabolic disorders occurring in children. Autoantibodies against pancreatic insulin-producing beta cells are important immunological and serological markers of T1D. Zinc transporter 8 autoantibody (ZnT8) is a recently identified autoantibody in T1D; however, no data on ZnT8 autoantibody in the Saudi Arabian population have been reported. Thus, we aimed to investigate the prevalence of islet autoantibodies (IA-2 and ZnT8) in adolescents and adults with T1D according to age and disease duration. (2) Methods: In total, 270 patients were enrolled in this cross-sectional study. After meeting the study's inclusion and exclusion criteria, 108 patients with T1D (50 men and 58 women) were assessed for T1D autoantibody levels. Serum ZnT8 and IA-2 autoantibodies were measured using commercial enzyme-linked immunosorbent assay kits. (3) Results: IA-2 and ZnT8 autoantibodies were present in 67.6% and 54.6% of patients with T1D, respectively. Autoantibody positivity was found in 79.6% of the patients with T1D. Both the IA-2 and ZnT8 autoantibodies were frequently observed in adolescents. The prevalence of IA-2 and ZnT8 autoantibodies in patients with a disease duration < 1 year was 100% and 62.5%, respectively, which declined with an increase in disease duration (p < 0.020). Logistic regression analysis revealed a significant relationship between age and autoantibodies (p < 0.004). (4) Conclusions: The prevalence of IA-2 and ZnT8 autoantibodies in the Saudi Arabian T1D population appears to be higher in adolescents. The current study also showed that the prevalence of autoantibodies decreased with disease duration and age. IA-2 and ZnT8 autoantibodies are important immunological and serological markers for T1D diagnosis in the Saudi Arabian population.

Impact of Zinc Transport Mechanisms on Embryonic and Brain Development

The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.

CTLA-4 CT-60 A/G and CTLA-4 1822 C/T Gene Polymorphisms in Indonesians with Type 1 Diabetes Mellitus

Introduction

CTLA-4 gene polymorphism plays an important role in children with type 1 diabetes mellitus (T1DM). However, data on this subject vary among different races and ethnics.

Purpose

To analyze CTLA-4 CT-60 A/G and CTLA-4 1822 C/T gene polymorphism among children with T1DM compared to control.

Patients and Methods

The CTLA-4 CT-60 A/G and CTLA-4 1822 C/T gene polymorphism in children with T1DM using polymerase chain reaction-restriction fragment length polymorphism in 25 T1DM and 25 controls. The inclusion criteria were patients regularly controlled at the Pediatric Endocrine Outpatient Clinic of Dr. Soetomo Hospital, aged 4-18 years and willing to join this study and the exclusion criteria were T1DM patients hospitalized in the pediatric intensive care unit. In the control group, the inclusion criteria were healthy children, aged 4-18 years and willing to join this study. The exclusion criteria included children with ongoing infection, history of other autoimmune diseases, allergies, or malignancy.

Results

The mean age was 12.48 years old, and the mean of T1DM onset was 9.28 years old. The CTLA-4 1822 T allele observed in 62% T1DM and 56% in control (p = 0.388, OR = 0.78, 95% CI = 0.44-1.37) and CTLA-4 CT-60 G allele observed in 52% T1DM and 58% in control (p = 0.393, OR = 1.27, 95% CI = 0.73-2.22). The C/T genotypes was significantly higher in control group (p = 0.045, OR = 3.27, 95% CI = 1.00-10.62). The A/G genotypes was commonly found in control group (p = 0.765, OR = 1.20, 95% CI = 0.37-3.86). The Javanese was the dominant ethnic group in our study.

Conclusion

The frequency of CTLA-4 CT-60 A/G polymorphism almost equivalent in T1DM and control group. However, CTLA-4 1822 C/T polymorphism was more prevalent in the control group; thus, this genotype may have a protective effect against T1DM.

Autoantibodies to Zinc Transporter 8 and SLC30A8 Genotype in Type 1 Diabetes Childhood: A Pioneering Study in North Africa

BACKGROUND

Type 1 diabetes (T1D) occurs as a result of insulin deficiency due to destructive lesions of pancreatic β cells. In addition to classical autoantibodies (Abs) to islet cell antigens, antizinc transporter 8 Abs (ZnT8-Ab) have been recently described in T1D.

OBJECTIVE

As no data on ZnT8-Ab in Tunisian patients has been reported, we aim to evaluate the relationships between ZnT8-Ab, ZnT8 coding gene (SLC30A8) promoter polymorphism, and T1D risk in newly diagnosed children.

METHODS

ZnT8-Ab were measured in the serum of T1D newly affected children (n = 156) who were admitted to the pediatric department of the Hedi Chaker University Hospital of Sfax. Rs13266634 was genotyped in T1D children and 79 of their first-degree parents. The SPSS software was used to analyze the serological data. Allelic association analysis was conducted with family-based association tests implemented in the FBAT program v1.5.1.

RESULTS

ZnT8-Ab was detected in 66/156 (42.3%) of T1D newly diagnosed children. Among them, 6 (9%) presented ZnT8-Ab as the only humoral marker. The inclusion of ZnT8-Ab increased the number of Ab-positive patients to 90% and reduced the negative ones by 27%. There was no evidence of any overtransmission of any allele of the rs13266634 C/T polymorphism from parents to affected T1D children, nor of any correlation with any clinical or serological parameter. After the T1D disease onset age adjustment, a significant association was observed with the C allele suggesting that it could have a susceptibility role.

CONCLUSION

ZnT8-Ab appears as a relevant diagnostic marker for T1D in Tunisian children, especially at the onset of the disease as teenagers.

Ten years follow up of first degree relatives of type 1 diabetes patients: presence of autoimmune biomarkers and the progression to diabetes in a retrospective cohort

OBJECTIVE

The aim of the study was to assess the autoimmunity in first degrees relatives (FDR) of patients with type 1 diabetes (T1DM) and the progression to T1DM after 10 years of follow up in the Brazilian population.

METHODS

Non-diabetic FDR of T1DM patients were interviewed and blood was drawn for autoantibodies measurement (GADA, IA-2A, IAA, ZnT8A). Serum samples were analyzed by standard radioligand binding assays performed at the Federal University of Rio de Janeiro (GADA, IAA and IA2A), and at the Skäne University Hospital, Sweden (ZnT8A). The FDR were interviewed by phone after 10 years to determine if they had developed T1DM. Descriptive statistical analysis was performed and results were described as means and standard deviation (SD).

RESULTS

81 individuals were analyzed. Thirteen subjects had positive autoantibodies associated with T1DM.10 were positive for 1 autoantibody and 3 subjects were positive for multiple autoantibodies (1 of them showed positivity for 2 autoantibodies - GADA, ZnT8A - and the other two were positive for 3 autoantibodies - GADA, IA2A, ZnT8A). The 3 subjects with multiple positive autoantibodies developed T1DM within 10 years.

CONCLUSION

In Brazilian FDR of T1DM patients, the positivity for multiple autoantibodies indicate a greater chance of progression to T1DM, similar to observed in Caucasians. ZnT8A was helpful in the risk assessment for T1DM development.

Zinc as a Biomarker of Cardiovascular Health

The importance of zinc (Zn) for cardiovascular health continuously gains recognition. As shown earlier, compromised Zn homeostasis and prolonged inflammation are common features in various cardiovascular diseases (CVDs). Similarly, Zn biochemistry alters several vascular processes, and Zn status is an important feature of cardiovascular health. Zn deficiency contributes to the development of CVDs; thus, Zn manipulations, including Zn supplementation, are beneficial for preventing and treating numerous cardiovascular (CV) disorders. Finally, additional long-term, well-designed studies, performed in various population groups, should be pursued to further clarify significant relationships between Zn and CVDs.

Zinc transporter 8 (ZnT8) autoantibody prevalence in black South African participants with type 1 diabetes

BACKGROUND

Autoantibodies to β-cell specific antigens are markers of type 1 diabetes. The most recently identified autoantibodies are targeted to the zinc transporter 8 (ZnT8) protein located in the membrane of β-cell insulin secretory granules. The prevalence of ZnT8 autoantibodies in newly diagnosed participants with type 1 diabetes has been found to range from 33 to 80 %. Due to the lack of data on the immunological aetiology of type 1 diabetes in African populations, this study aimed to determine the prevalence of ZnT8 autoantibodies in black South Africans with type 1 diabetes and whether ZnT8 autoantibody positivity was associated with age at diagnosis and disease duration.

METHODS

Participants with type 1 diabetes and controls were recruited from the greater Johannesburg area, South Africa. Positivity for ZnT8, GAD65 and IA2 autoantibodies was determined by ELISA.

RESULTS

Participants with type 1 diabetes (n = 183) and controls (n = 49) were matched for age (29.1 ± 9.53 vs. 27.3 ± 7.29, respectively; p = 0.248). The mean age at diagnosis for participants with type 1 diabetes was 20.8 ± 8.46 years. The prevalence of ZnT8 autoantibody positivity was 17.5 % (32 of 183) in participants with type 1 diabetes with a median disease duration of 7.00 [2.00; 11.0] years. ZnT8 autoantibody prevalence in newly diagnosed participants (< 1 year duration) was 27.3 % (6 of 22). Logistic regression analysis found an association between ZnT8 autoantibody positivity and shorter disease duration (OR: 0.9 (0.81-1.00); p = 0.042). In addition, ZnT8 autoantibody positivity was significantly associated with an increased chance of being GAD65 (OR: 3.37 (1.10-10.3)) and IA2 (OR: 8.63 (2.82-26.4)) autoantibody positive. Multiple regression analysis found no association between ZnT8 autoantibody positivity and age at diagnosis. However, the presence of ≥ 2 autoantibodies was associated with a younger age at diagnosis of type 1 diabetes when compared to participants with ≤ 1 autoantibody (B = -5.270; p = 0.002).

CONCLUSIONS

The presence of ZnT8 autoantibodies was not related to a younger age at diagnosis in black South African patients with type 1 diabetes. However, the greater the numbers of autoantibodies present in an individual the earlier the age at diagnosis. ZnT8 autoantibodies decline with disease duration in the black South African population.

SNPs in the 3'-untranslated region of SLC30A8 confer risk of type 2 diabetes mellitus in a south-east Iranian population: Evidences from case-control and bioinformatics studies

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a heterogenic disease with increasing incidence. The SLC30A8 gene encodes an islet zinc transporter (ZnT8), and its variants have been associated with glucose and pro-insulin levels. This study was aimed to examine the effects of a missense variant (rs13266634 C/T), and two 3'UTR variants (rs2466294 C/G and rs2466293 T/C) in SLC30A8 gene on T2DM risk in a south-east Iranian population.

METHODS

In this experiment, 450 patients diagnosed with T2DM and 453 healthy subjects from the same geographic area were enrolled. Genotypes were amplified using the ARMS-PCR method. In silico analyses were performed to determine the effects of the variants on the local structure of mRNA, splicing patterns, and potential miRNA-gene interactions as well.

RESULTS

Significant differences were noticed between cases and controls regarding the genotypic and allelic distribution of the studied variants. As regards rs2466293 and rs2466294 variants, enhanced risk of T2DM was found under allelic, dominant, recessive, and codominant models (OR > 1). Besides, different genetic models of rs13266634 were associated with decreased risk of T2DM (OR < 1). Bioinformatics analyses indicated that the rs2466293 variant might influence the binding of some miRNAs, while the G-allele of rs2466294 decreased the stability of SLC30A8-mRNA.

CONCLUSIONS

In our population, both SNPs in the 3'-untranslated region of SLC30A8 increased the risk of T2DM, while the rs13266634 variant showed a protective association against T2DM susceptibility. Investigating the effects of other variants in this gene or other ZnTs can further indicate such associations in subjects from the same ethnicity.

A UNIQUE CASE OF ATEZOLIZUMAB-INDUCED AUTOIMMUNE DIABETES

Objective

Immunotherapy is a novel treatment that can cause autoimmune diabetes in rare cases. More cases occur following use of the inhibitor to the protein programmed cell death-1 rather than the inhibitor to programmed cell death-ligand 1.

Methods

We report a unique case of autoimmune diabetes following atezolizumab use.

Results

A 55-year-old, Aboriginal Australian female with no prior history of diabetes was commenced on atezolizumab for recurrent squamous cell lung carcinoma. Two months following its commencement, there was the onset of fatigue, polyuria, polydipsia, and new hyperglycemia. Subsequently she was found to have a borderline-low C peptide level of 0.6 nmol/L (reference range is 0.5 to 1.0 nmol/L), and positive zinc transporter-8 antibodies. Following the diagnosis of autoimmune diabetes, 5 units of glargine insulin was commenced which maintained euglycemia and resolved her symptoms of hyperglycemia.

Conclusion

There are few case reports of atezolizumab-induced autoimmune diabetes. We present the first case associated with zinc transporter-8 antibodies, and a unique case of autoimmune diabetes in a patient of Aboriginal Australian background.

Zinc transporter 8 autoantibodies complement glutamic acid decarboxylase and insulinoma-associated antigen-2 autoantibodies in the identification and characterization of Japanese type 1 diabetes

AIMS/INTRODUCTION

This study aimed to investigate the significance of zinc transporter 8 autoantibody (ZnT8A) in identifying and characterizing autoimmune-mediated type 1 diabetes in Japanese individuals.

METHODS

ZnT8A were determined in 324 patients with type 1 diabetes, 191 phenotypic type 2 diabetes and 288 healthy control individuals using bridging-type enzyme-linked immunosorbent assay in addition to autoantibodies to glutamic acid decarboxylase and insulinoma-associated antigen-2.

RESULTS

We set a cut-off value of 10.0 U/mL, and 25% of the type 1 diabetic patients had ZnT8A levels exceeding this level. The prevalence of ZnT8A was significantly higher in patients with acute-onset type 1 diabetes than in those with slowly progressive and fulminant type 1 diabetes (P < 0.05). ZnT8A were more frequent in patients aged ≤10 years, but less frequent in patients with duration ≥5 years (P < 0.05). ZnT8A were detected in 5.2% of phenotypic type 2 diabetic patients, with 90% of these being ZnT8A-single-positive. Furthermore, the ZnT8A levels in the phenotypic type 2 diabetes cohort (143.8 ± 194.9 U/mL) were significantly higher than those in the type 1 diabetes cohort (22.9 ± 8.3 U/mL, P < 0.05). In the acute-onset and slowly progressive type 1 diabetic patients with duration ≤5 years, additional measurement of glutamic acid decarboxylase autoantibodies significantly increased the disease sensitivity in patients aged ≤10 years, but not in patients aged ≥11 years (11.7 vs 3.6%, P < 0.05). Multivariate analysis showed that ZnT8A positivity was independently associated with age at sampling and insulinoma-associated antigen-2 autoantibody positivity.

CONCLUSIONS

These results suggest that the bridging-type ZnT8A enzyme-linked immunosorbent assay might provide a valuable additional marker for Japanese patients with type 1 diabetes, which could, in turn, allow for an increase in the number of identifiable cases and differentiate clinical phenotypes.

Hierarchical Order of Distinct Autoantibody Spreading and Progression to Type 1 Diabetes in the TEDDY Study

OBJECTIVE

The first-appearing β-cell autoantibody has been shown to influence risk of type 1 diabetes (T1D). Here, we assessed the risk of autoantibody spreading to the second-appearing autoantibody and further progression to clinical disease in The Environmental Determinants of Diabetes in the Young (TEDDY) study.

RESEARCH DESIGN AND METHODS

Eligible children with increased HLA-DR-DQ genetic risk for T1D were followed quarterly from age 3 months up to 15 years for development of a single first-appearing autoantibody (GAD antibody [GADA], insulin autoantibody [IAA], or insulinoma antigen-2 autoantibody [IA-2A]) and subsequent development of a single second-appearing autoantibody and progression to T1D. Autoantibody positivity was defined as positivity for a specific autoantibody at two consecutive visits confirmed in two laboratories. Zinc transporter 8 autoantibody (ZnT8A) was measured in children who developed another autoantibody.

RESULTS

There were 608 children who developed a single first-appearing autoantibody (IAA, n = 282, or GADA, n = 326) with a median follow-up of 12.5 years from birth. The risk of a second-appearing autoantibody was independent of GADA versus IAA as a first-appearing autoantibody (adjusted hazard ratio [HR] 1.12; 95% CI 0.88-1.42; P = 0.36). Second-appearing GADA, IAA, IA-2A, or ZnT8A conferred an increased risk of T1D compared with children who remained positive for a single autoantibody, e.g., IAA or GADA second (adjusted HR 6.44; 95% CI 3.78-10.98), IA-2A second (adjusted HR 16.33; 95% CI 9.10-29.29; P < 0.0001), or ZnT8A second (adjusted HR 5.35; 95% CI 2.61-10.95; P < 0.0001). In children who developed a distinct second autoantibody, IA-2A (adjusted HR 3.08; 95% CI 2.04-4.65; P < 0.0001) conferred a greater risk of progression to T1D as compared with GADA or IAA. Additionally, both a younger initial age at seroconversion and shorter time to the development of the second-appearing autoantibody increased the risk for T1D.

CONCLUSIONS

The hierarchical order of distinct autoantibody spreading was independent of the first-appearing autoantibody type and was age-dependent and augmented the risk of progression to T1D.

Association of Zinc Transporter-8 Autoantibody (ZnT8A) with Type 1 Diabetes Mellitus

BACKGROUND

Zinc transporter 8 autoantibody (ZnT8A), discovered through bioinformatics, is identified as another major biomarker for type 1 diabetes mellitus (T1DM), expanding the panel of diagnostic autoantibodies. The absence of standard autoantibodies in T1DM patients and the presence of ZnT8A in individuals before disease development has led the researchers to evaluate ZnT8A to gather information about the frequency and its association. Therefore, we aim to find out the concentration of ZnT8A and its association with T1DM.

METHODS

A case-control study with 25 type 1 diabetes mellitus patients and 25 first-degree relatives of cases as controls was conducted at Ziauddin University in collaboration with the Baqai Institute of Diabetology and Endocrinology (BIDE), Karachi. Demographic data were collected from patients on a standard questionnaire. Blood samples were collected, after approval from Ziauddin Ethics Review Committee, from subjects and serum was separated to estimate ZnT8A by using sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean age at diagnosis of T1DM patients was 13.40±5.05 years, and the duration of diabetes was 7.74±5.85 years. The frequency of ZnT8A was found higher in cases (19 (76%)) compared to controls (6 (24%)). ZnT8A concentrations were significantly higher in cases (13.82 ng/ml) compared to the controls (8.78 ng/ml; p= 0.024). The cut-off value of 9 ng/ml was selected for measuring sensitivity, specificity, and accuracy, which were determined as 76%, 76%, and 76%, respectively.

CONCLUSIONS

ZnT8A was found significantly associated with T1DM. Subjects with ZnT8A values ≥ 9 ng/ml are 10 times more at risk to develop T1DM (p = 0.000).

Solute carrier transporters: the metabolic gatekeepers of immune cells

Solute carrier (SLC) transporters meditate many essential physiological functions, including nutrient uptake, ion influx/efflux, and waste disposal. In its protective role against tumors and infections, the mammalian immune system coordinates complex signals to support the proliferation, differentiation, and effector function of individual cell subsets. Recent research in this area has yielded surprising findings on the roles of solute carrier transporters, which were discovered to regulate lymphocyte signaling and control their differentiation, function, and fate by modulating diverse metabolic pathways and balanced levels of different metabolites. In this review, we present current information mainly on glucose transporters, amino-acid transporters, and metal ion transporters, which are critically important for mediating immune cell homeostasis in many different pathological conditions.

SLC30A8 Gene rs13266634 C/T Polymorphism in Children with Type 1 Diabetes in Tamil Nadu, India

Objective

Zinc transporter 8 (ZnT8) is a multi-transmembrane protein situated in the insulin secretory granule of the islets of β-cells and is identified as a novel auto-antigen in type 1 diabetes (T1D). The gene coding for ZnT8, solute carrier family 30 member 8 (SLC30A8) is located on chromosome 8q24.11. This study aimed to identify the association of SLC30A8 rs13266634 C/T gene polymorphism with T1D in a sample of T1D children in Tamil Nadu, India.

Methods

The family based study was conducted in 121 T1D patients and 214 of their family members as controls. The SLC30A8 gene rs13266634 C/T polymorphism was evaluated by polymerase chain reaction-restriction fragment length polymorphism.

Results

No significant differences were observed in either allele (odds ratio: 0.92; confidence interval: 0.33-2.58; p=0.88) and genotype (CC: p=0.74; CT: p=0.82; TT: p=0.80) frequencies of rs13266634 C/T between T1D patients and controls. Transmission disequilibrium test has identified over-transmission of mutant T allele from parents to affected children (T: U=9:7) without statistical significance. Metaanalysis on the overall effects of rs13266634 C allele frequency was not different (p=0.10 and Pheterogeneity=0.99) in T1D patients as compared to the controls.

Conclusion

The present study along with the meta-analysis does not show any substantial association of the rs13266634 C/T polymorphism with T1D development in this population.

Prokaryotic expression and characterization of the heterodimeric construction of ZnT8 and its application for autoantibodies detection in diabetes mellitus

Background

In the present work we described the recombinant production and characterization of heterodimeric construction ZnT8-Arg-Trp325 fused to thioredoxin using a high-performance expression system such as Escherichia coli. In addition, we apply this novel recombinant antigen in a non-radiometric method, with high sensitivity, low operational complexity and lower costs.

Results

ZnT8 was expressed in E. coli as a fusion protein with thioredoxin (TrxZnT8). After 3 h for induction, recombinant protein was obtained from the intracellular soluble fraction and from inclusion bodies and purified by affinity chromatography. The expression and purification steps, analyzed by SDS-PAGE and western blot, revealed a band compatible with TrxZnT8 expected theoretical molecular weight (≈ 36.8 kDa). The immunochemical ability of TrxZnT8 to compete with [³⁵S]ZnT8 (synthesized with rabbit reticulocyte lysate system) was assessed qualitatively by incubating ZnT8A positive patient sera in the presence of 0.2–0.3 μM TrxZnT8. Results were expressed as standard deviation scores (SDs). All sera became virtually negative under antigen excess (19.26–1.29 for TrxZnT8). Also, radiometric quantitative competition assays with ZnT8A positive patient sera were performed by adding TrxZnT8 (37.0 pM–2.2 µM), using [³⁵S]ZnT8. All dose–response curves showed similar protein concentration that caused 50% inhibition (14.9–0.15 nM for TrxZnT8). On the other hand, preincubated bridge ELISA for ZnT8A detection was developed. This assay showed 51.7% of sensitivity and 97.1% of specificity.

Conclusions

It was possible to obtain with high-yield purified heterodimeric construction of ZnT8 in E. coli and it was applied in cost-effective immunoassay for ZnT8A detection.

Electronic supplementary material

The online version of this article (10.1186/s12934-017-0816-4) contains supplementary material, which is available to authorized users.