Viral infections as potential triggers of type 1 diabetes

The relationship between SARS-CoV-2 infection and type 1 diabetes mellitus

Environmental factors, in particular viral infections, are thought to have an important role in the pathogenesis of type 1 diabetes mellitus (T1DM). The COVID-19 pandemic reinforced this hypothesis as many observational studies and meta-analyses reported a notable increase in the incidence of T1DM following infection with SARS-CoV-2 as well as an association between SARS-CoV-2 infection and the risk of new-onset T1DM. Experimental evidence suggests that human β-cells express SARS-CoV-2 receptors and that SARS-CoV-2 can infect and replicate in β-cells, resulting in structural or functional alterations of these cells. These alterations include reduced numbers of insulin-secreting granules, impaired pro-insulin (or insulin) secretion, and β-cell transdifferentiation or dedifferentiation. The inflammatory environment induced by local or systemic SARS-CoV-2 infection might result in a set of signals (such as pro-inflammatory cytokines) that lead to β-cell alteration or apoptosis or to a bystander activation of T cells and disruption of peripheral tolerance that triggers autoimmunity. Other mechanisms, such as viral persistence, molecular mimicry and activation of endogenous human retroviruses, are also likely to be involved in the pathogenesis of T1DM following SARS-CoV-2 infection. This Review addresses the issue of the involvement of SARS-CoV-2 infection in the development of T1DM using evidence from epidemiological, clinical and experimental studies.

Virus-induced diabetes mellitus: revisiting infection etiology in light of SARS-CoV-2

Diabetes mellitus (DM) is comprised of two predominant subtypes: type 1 diabetes mellitus (T1DM), accounting for approximately 5 % of cases worldwide and resulting from autoimmune destruction of insulin-producing β-cells, and type 2 (T2DM), accounting for approximately 95 % of cases globally and characterized by the inability of pancreatic β-cells to meet the demand for insulin due to a relative β-cell deficit in the setting of peripheral insulin resistance. Both types of DM involve derangement of glucose metabolism and are metabolic diseases generally considered to be initiated by a combination of genetic and environmental factors. Viruses have been reported to play a role as infectious etiological factors in the initiation of both types of DM in predisposed individuals. Among the reported viral infections causing DM in humans, the most studied include coxsackie B virus, cytomegalovirus and hepatitis C virus. The recent COVID-19 pandemic has highlighted the diabetogenic potential of SARS-CoV-2, rekindling interest in the field of virus-induced diabetes (VID). This review discusses the reported mechanisms of viral-induced DM, addressing emerging concepts in VID, as well as highlighting areas where knowledge is lacking, and further investigation is warranted.

Progress in experimental models to investigate the in vivo and in vitro antidiabetic activity of drugs

Diabetes mellitus is one of the world's most prevalent and complex metabolic disorders, and it is a rapidly growing global public health issue. It is characterized by hyperglycemia, a condition involving a high blood glucose level brought on by deficiencies in insulin secretion, decreased activity of insulin, or both. Prolonged effects of diabetes include cardiovascular problems, retinopathy, neuropathy, nephropathy, and vascular alterations in both macro- and micro-blood vessels. In vivo and in vitro models have always been important for investigating and characterizing disease pathogenesis, identifying targets, and reviewing novel treatment options and medications. Fully understanding these models is crucial for the researchers so this review summarizes the different experimental in vivo and in vitro model options used to study diabetes and its consequences. The most popular in vivo studies involves the small animal models, such as rodent models, chemically induced diabetogens like streptozotocin and alloxan, and the possibility of deleting or overexpressing a specific gene by knockout and transgenic technologies on these animals. Other models include virally induced models, diet/nutrition induced diabetic animals, surgically induced models or pancreatectomy models, and non-obese models. Large animals or non-rodent models like porcine (pig), canine (dog), nonhuman primate, and Zebrafish models are also outlined. The in vitro models discussed are murine and human beta-cell lines and pancreatic islets, human stem cells, and organoid cultures. The other enzymatic in vitro tests to assess diabetes include assay of amylase inhibition and inhibition of α-glucosidase activity.

A Composite Biomarker Signature of Type 1 Diabetes Risk Identified via Augmentation of Parallel Multi-Omics Data from a Small Cohort

Background

Biomarkers of early pathogenesis of type 1 diabetes (T1D) are crucial to enable effective prevention measures in at-risk populations before significant damage occurs to their insulin producing beta-cell mass. We recently introduced the concept of integrated parallel multi-omics and employed a novel data augmentation approach which identified promising candidate biomarkers from a small cohort of high-risk T1D subjects. We now validate selected biomarkers to generate a potential composite signature of T1D risk.

Methods

Twelve candidate biomarkers, which were identified in the augmented data and selected based on their fold-change relative to healthy controls and cross-reference to proteomics data previously obtained in the expansive TEDDY and DAISY cohorts, were measured in the original samples by ELISA.

Results

All 12 biomarkers had established connections with lipid/lipoprotein metabolism, immune function, inflammation, and diabetes, but only 7 were found to be markedly changed in the high-risk subjects compared to the healthy controls: ApoC1 and PON1 were reduced while CETP, CD36, FGFR1, IGHM, PCSK9, SOD1, and VCAM1 were elevated.

Conclusions

Results further highlight the promise of our data augmentation approach in unmasking important patterns and pathologically significant features in parallel multi-omics datasets obtained from small sample cohorts to facilitate the identification of promising candidate T1D biomarkers for downstream validation. They also support the potential utility of a composite biomarker signature of T1D risk characterized by the changes in the above markers.

Benefits and risks of drug combination therapy for diabetes mellitus and its complications: a comprehensive review

Diabetes is a chronic metabolic disease, and its therapeutic goals focus on the effective management of blood glucose and various complications. Drug combination therapy has emerged as a comprehensive treatment approach for diabetes. An increasing number of studies have shown that, compared with monotherapy, combination therapy can bring significant clinical benefits while controlling blood glucose, weight, and blood pressure, as well as mitigating damage from certain complications and delaying their progression in diabetes, including both type 1 diabetes (T1D), type 2 diabetes (T2D) and related complications. This evidence provides strong support for the recommendation of combination therapy for diabetes and highlights the importance of combined treatment. In this review, we first provided a brief overview of the phenotype and pathogenesis of diabetes and discussed several conventional anti-diabetic medications currently used for the treatment of diabetes. We then reviewed several clinical trials and pre-clinical animal experiments on T1D, T2D, and their common complications to evaluate the efficacy and safety of different classes of drug combinations. In general, combination therapy plays a pivotal role in the management of diabetes. Integrating the effectiveness of multiple drugs enables more comprehensive and effective control of blood glucose without increasing the risk of hypoglycemia or other serious adverse events. However, specific treatment regimens should be tailored to individual patients and implemented under the guidance of healthcare professionals.

Clinical and biological heterogeneity of multisystem inflammatory syndrome in adults following SARS-CoV-2 infection: a case series

Importance

Multisystem inflammatory syndrome in adults (MIS-A) is a poorly understood complication of SARS-CoV-2 infection with significant morbidity and mortality.

Objective

Identify clinical, immunological, and histopathologic features of MIS-A to improve understanding of the pathophysiology and approach to treatment.

Design

Three cases of MIS-A following SARS-CoV-2 infection were clinically identified between October 2021 - March 2022 using the U.S. Centers for Disease Control and Prevention diagnostic criteria. Clinical, laboratory, imaging, and tissue data were assessed.

Findings

All three patients developed acute onset cardiogenic shock and demonstrated elevated inflammatory biomarkers at the time of hospital admission that resolved over time. One case co-occurred with new onset Type 1 diabetes and sepsis. Retrospective analysis of myocardial tissue from one case identified SARS-CoV-2 RNA. All three patients fully recovered with standard of care interventions plus immunomodulatory therapy that included intravenous immunoglobulin, corticosteroids, and in two cases, anakinra.

Conclusion

MIS-A is a severe post-acute sequela of COVID-19 characterized by systemic elevation of inflammatory biomarkers. In this series of three cases, we find that although clinical courses and co-existent diseases vary, even severe presentations have potential for full recovery with prompt recognition and treatment. In addition to cardiogenic shock, glucose intolerance, unmasking of autoimmune disease, and sepsis can be features of MIS-A, and SARS-CoV-2 myocarditis can lead to a similar clinical syndrome.

Management of Invasive Infections in Diabetes Mellitus: A Comprehensive Review

Patients with diabetes often have more invasive infections, which may lead to an increase in morbidity. The hyperglycaemic environment promotes immune dysfunction (such as the deterioration of neutrophil activity, antioxidant system suppression, and compromised innate immunity), micro- and microangiopathies, and neuropathy. A greater number of medical interventions leads to a higher frequency of infections in diabetic patients. Diabetic individuals are susceptible to certain conditions, such as rhino-cerebral mucormycosis or aspergillosis infection. Infections may either be the primary symptom of diabetes mellitus or act as triggers in the intrinsic effects of the disease, such as diabetic ketoacidosis and hypoglycaemia, in addition to increasing morbidity. A thorough diagnosis of the severity and origin of the infection is necessary for effective treatment, which often entails surgery and extensive antibiotic use. Examining the significant issue of infection in individuals with diabetes is crucial. Comprehensive research should examine why infections are more common amongst diabetics and what the preventive treatment strategies could be.

Influenza Prevalence and Vaccine Efficacy among Diabetic Patients in Qatar

Seasonal influenza viruses may lead to severe illness and mortality in patients with comorbidities, including Diabetes Mellitus (DM). Vaccination against influenza in DM patients may reduce influenza incidence and severity. Before the emergence of the COVID-19 pandemic, influenza infections were the most prevalent respiratory infections in Qatar. Still, reports about influenza prevalence and vaccine efficacy in DM patients have not been reported. This study aimed to analyze influenza prevalence among other respiratory infections and assess influenza vaccine efficacy in DM patients in Qatar. Statistical analysis was performed on data obtained from Hamad Medical Corporation (HMC) database for patients that visited the emergency department (ED) with respiratory-like illnesses. The analysis was done for the period between January 2016 to December 2018. Among 17,525 patients who visited HMC-ED with clinical symptoms of respiratory infections, 2611(14.9%) were reported to have DM. Among DM patients, influenza was the most prevalent respiratory pathogen at 48.9%. Influenza virus A (IVA) was the most circulating type, contributing to 38.4%, followed by IVB contributing to 10.4% of total respiratory infections. Among the typed IVA-positive cases, 33.4% were H1N1, and 7.7% were H3N2. A significant decrease in influenza infections was reported in vaccinated DM patients (14.5%) when compared to non-vaccinated patients (18.9%) (p-value = 0.006). However, there was no significant relaxation in the clinical symptoms among vaccinated DM patients compared to their non-vaccinated counterparts. In conclusion, influenza was the most common etiology for respiratory viral infection among diabetic patients at the leading healthcare provider in Qatar. Although vaccination reduced the incidence rate among DM patients, it was less effective in preventing symptoms. Further studies on a larger cohort and for a more extended period are required to investigate influenza prevalence and vaccine efficacy among DM patients.

Understanding Insulin in the Age of Precision Medicine and Big Data: Under-Explored Nature of Genomics

Insulin is amongst the human genome's most well-studied genes/proteins due to its connection to metabolic health. Within this article, we review literature and data to build a knowledge base of Insulin (INS) genetics that influence transcription, transcript processing, translation, hormone maturation, secretion, receptor binding, and metabolism while highlighting the future needs of insulin research. The INS gene region has 2076 unique variants from population genetics. Several variants are found near the transcriptional start site, enhancers, and following the INS transcripts that might influence the readthrough fusion transcript INS-IGF2. This INS-IGF2 transcript splice site was confirmed within hundreds of pancreatic RNAseq samples, lacks drift based on human genome sequencing, and has possible elevated expression due to viral regulation within the liver. Moreover, a rare, poorly characterized African population-enriched variant of INS-IGF2 results in a loss of the stop codon. INS transcript UTR variants rs689 and rs3842753, associated with type 1 diabetes, are found in many pancreatic RNAseq datasets with an elevation of the 3'UTR alternatively spliced INS transcript. Finally, by combining literature, evolutionary profiling, and structural biology, we map rare missense variants that influence preproinsulin translation, proinsulin processing, dimer/hexamer secretory storage, receptor activation, and C-peptide detection for quasi-insulin blood measurements.

Virus induced dysbiosis promotes type 1 diabetes onset

Autoimmune disorders are complex diseases of unclear etiology, although evidence suggests that the convergence of genetic susceptibility and environmental factors are critical. In type 1 diabetes (T1D), enterovirus infection and disruption of the intestinal microbiota are two environmental factors that have been independently associated with T1D onset in both humans and animal models. However, the possible interaction between viral infection and the intestinal microbiota remains unknown. Here, we demonstrate that Coxsackievirus B4 (CVB4), an enterovirus that accelerates T1D onset in non-obese diabetic (NOD) mice, induced restructuring of the intestinal microbiome prior to T1D onset. Microbiome restructuring was associated with an eroded mucosal barrier, bacterial translocation to the pancreatic lymph node, and increased circulating and intestinal commensal-reactive antibodies. The CVB4-induced change in community composition was strikingly similar to that of uninfected NOD mice that spontaneously developed diabetes, implying a mutual "diabetogenic" microbiome. Notably, members of the Bifidobacteria and Akkermansia genera emerged as conspicuous members of this diabetogenic microbiome, implicating these taxa, among others, in diabetes onset. Further, fecal microbiome transfer (FMT) of the diabetogenic microbiota from CVB4-infected mice enhanced T1D susceptibility and led to diminished expression of the short chain fatty acid receptor GPR43 and fewer IL-10-expressing regulatory CD4⁺ T cells in the intestine of naïve NOD recipients. These findings support an overlap in known environmental risk factors of T1D, and suggest that microbiome disruption and impaired intestinal homeostasis contribute to CVB-enhanced autoreactivity and T1D.

Effects of Lifetime Exposures to Environmental Contaminants on the Adult Gut Microbiome

Emerging experimental evidence indicates that toxicant-induced alterations in gut microbiota composition and activity may affect host homeostasis. However, data from human studies are scarce; to our knowledge, no previous studies have quantified the association of lifetime exposure to environmental chemicals, across multiple time points, with the composition of the adult gut microbiome. Here we studied 124 individuals born in the Faroe Islands in 1986-1987 who were followed approximately every seven years from birth through age 28 years. Organochlorine compounds, including polychlorinated biphenyls (PCBs) and pesticides, perfluoroalkyl substances (PFAS), and mercury (Hg), were measured in cord blood and longitudinally in participants' blood. At age 28, the gut microbiome was assessed using shotgun metagenomic sequencing. Historical contaminant exposures had little direct effect on the adult gut microbiome, while a small number of fastidious anaerobes were weakly linked to recent PFAS/PFOS exposures at age 28. In this cohort, our findings suggest no lasting effects of early life exposures on adult gut microbial composition, but proximal exposures may contribute to gut microbiome alterations. The methods developed and used for this investigation may help in future identification of small but lasting impacts of environmental toxicant exposure on the gut microbiome.

The interferon regulatory factors, a double-edged sword, in the pathogenesis of type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease resulted from the unrestrained inflammatory attack towards the insulin-producing islet β cells. Although the exact etiology underlying T1D remains elusive, viral infections, especially those specific strains of enterovirus, are acknowledged as a critical environmental cue involved in the early phase of disease initiation. Viral infections could either directly impede β cell function, or elicit pathological autoinflammatory reactions for β cell killing. Autoimmune responses are bolstered by a massive body of virus-derived exogenous pathogen-associated molecular patterns (PAMPs) and the presence of β cell-derived damage-associated molecular patterns (DAMPs). In particular, the nucleic acid components and the downstream nucleic acid sensing pathways serve as the major effector mechanism. The endogenous retroviral RNA, mitochondrial DNA (mtDNA) and genomic fragments generated by stressed or dying β cells induce host responses reminiscent of viral infection, a phenomenon termed as viral mimicry during the early stage of T1D development. Given that the interferon regulatory factors (IRFs) are considered as hub transcription factors to modulate immune responses relevant to viral infection, we thus sought to summarize the critical role of IRFs in T1D pathogenesis. We discuss with focus for the impact of IRFs on the sensitivity of β cells to cytokine stimulation, the vulnerability of β cells to viral infection/mimicry, and the intensity of immune response. Together, targeting certain IRF members, alone or together with other therapeutics, could be a promising strategy against T1D.

Type 1 Diabetes and Associated Cardiovascular Damage: Contribution of Extracellular Vesicles in Tissue Crosstalk

Significance: Type 1 diabetes (T1D) is characterized by the autoimmune destruction of the insulin secreting β-cells, with consequent aberrant blood glucose levels. Hyperglycemia is the common denominator for most of the chronic diabetic vascular complications, which represent the main cause of life reduction in T1D patients. For this disease, three interlaced medical needs remain: understanding the underlying mechanisms involved in pancreatic β-cell loss; identifying biomarkers able to predict T1D progression and its related complications; recognizing novel therapeutic targets. Recent Advances: Extracellular vesicles (EVs), released by most cell types, were discovered to contain a plethora of different molecules (including microRNAs) with regulatory properties, which are emerging as mediators of cell-to-cell communication at the paracrine and endocrine level. Recent knowledge suggests that EVs may act as pathogenic factors, and be developed into disease biomarkers and therapeutic targets in the context of several human diseases. Critical Issues: EVs have been recently shown to sustain a dysregulated cellular crosstalk able to exacerbate the autoimmune response in the pancreatic islets of T1D; moreover, EVs were shown to be able to monitor and/or predict the progression of T1D and the insurgence of vasculopathies. Future Directions: More mechanistic studies are needed to investigate whether the dysregulation of EVs in T1D patients is solely reflecting the progression of diabetes and related complications, or EVs also directly participate in the disease process, thus pointing to a potential use of EVs as therapeutic targets/tools in T1D. Antioxid. Redox Signal. 36, 631-651.

Rational construction of controllable autoimmune diabetes model depicting clinical features

Through animal models, particularly non-obesity diabetes model (NOD), pathological understandings of human autoimmune diabetes have been gained. However, features of those mouse models and the human disease are not sufficiently analogous; it is therefore not unexpected that interventions based on the mouse data fail at an alarming rate in clinical settings. An improvised model that maximally resembles the real pathological course is highly desirable. Here we devised a 'double-hit' strategy, pancreas was first hit by chemical damage (streptozotocin, STZ) to unleash auto-antigens, then hit second time by transient immune-inflammation (regulatory T cell depletion). Comparing to NOD model, this strategy not only induced classical diabetic symptoms, but also depicted the crucial pathogenic features absent in conventional models, such as CD8+ T cell dominant infiltrates, strong ketoacidosis and epitope-specific T cell responses. In addition, this model allowed synchronized control of disease onset, permitting more refined temporal analysis of disease progression. We believe that this model would yield research outcomes with clinically relevant prediction power unattainable previously.

Incidence of Diabetic Ketoacidosis Among Pediatrics With Type 1 Diabetes Prior to and During COVID-19 Pandemic: A Meta-Analysis of Observational Studies

BACKGROUND

Previous reports suggest that the Coronavirus Disease-2019 (COVID-19) pandemic might have affected incidences of diabetic ketoacidosis (DKA) and new diagnoses of type 1 diabetes. This systematic review and meta-analysis aimed to estimate the risk of DKA, including severe DKA, during the COVID-19 pandemic versus the prior-to-COVID-19 period among pediatric patients with type 1 diabetes.

METHODS

PubMed and EMBASE were searched for observational studies investigating the risk of DKA among pediatric patients with type 1 diabetes during the COVID-19 pandemic and the prior-to-COVID-19 period. A random meta-analysis model was performed to estimate the relative risk of DKA during the COVID-19 pandemic compared to before the pandemic. Subgroup analyses were conducted based on the type 1 diabetes status, established or newly diagnosed. In addition, sensitivity analysis was conducted for studies that reported results from adjusted analysis for potential confounders using fixed effect model.

RESULTS

A total of 20 observational studies reported the risk of DKA, of which 18 reported the risk of severe DKA. The risks of DKA and severe DKA were 35% (RR 1.35, 95%CI 1.2-1.53, I² = 71%) and 76% (RR 1.76, 95%CI 1.33-2.33, I^{2 =} 44%) higher in the during-COVID-19 group compared to the prior-to-COVID-19 group, respectively. Among patients with newly diagnosed type 1 diabetes, the risk of DKA was 44% higher for the during-COVID-19 group compared to the prior-to-COVID-19 group (RR 1.44, 95%CI 1.26-1.65; I² = 64%). Only two studies reported the risk of DKA among patients with established type 1 diabetes and the cumulative risk was not statistically significant. In the sensitivity analysis, four studies reported an adjusted odds ratio (aOR) of the risk of DKA during COVID-19 compared to the prior-to-COVID-19 period. The fixed estimate from the meta-analysis found an increase in the risk of DKA in the during-COVID-19 group compared to the prior-to-COVID-19 group (aOR 2.04, 95%CI 1.66-2.50).

CONCLUSIONS

This study showed that DKA risk, especially the risk of severe DKA, has increased significantly during the pandemic. Healthcare systems must be aware and prepared for such an increase in DKA cases and take all necessary measures to prevent future spikes during the pandemic.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=272775, identifier PROSPERO [CRD42021272775].

Identification of viral-mediated pathogenic mechanisms in neurodegenerative diseases using network-based approaches

During the course of a viral infection, virus-host protein-protein interactions (PPIs) play a critical role in allowing viruses to replicate and survive within the host. These interspecies molecular interactions can lead to viral-mediated perturbations of the human interactome causing the generation of various complex diseases. Evidences suggest that viral-mediated perturbations are a possible pathogenic etiology in several neurodegenerative diseases (NDs). These diseases are characterized by chronic progressive degeneration of neurons, and current therapeutic approaches provide only mild symptomatic relief; therefore, there is unmet need for the discovery of novel therapeutic interventions. In this paper, we initially review databases and tools that can be utilized to investigate viral-mediated perturbations in complex NDs using network-based analysis by examining the interaction between the ND-related PPI disease networks and the virus-host PPI network. Afterwards, we present our theoretical-driven integrative network-based bioinformatics approach that accounts for pathogen-genes-disease-related PPIs with the aim to identify viral-mediated pathogenic mechanisms focusing in multiple sclerosis (MS) disease. We identified seven high centrality nodes that can act as disease communicator nodes and exert systemic effects in the MS-enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways network. In addition, we identified 12 KEGG pathways, 5 Reactome pathways and 52 Gene Ontology Immune System Processes by which 80 viral proteins from eight viral species might exert viral-mediated pathogenic mechanisms in MS. Finally, our analysis highlighted the Th17 differentiation pathway, a disease communicator node and part of the 12 underlined KEGG pathways, as a key viral-mediated pathogenic mechanism and a possible therapeutic target for MS disease.

The microbiome and rodent models of immune mediated diseases

Over the last six decades production of laboratory rodents have been refined with the aim of eliminating all pathogens, which could influence research results. This has, however, also created rodents with little diversity in their microbiota. Until 10 years ago the impact of the microbiota on the outcome of rodent studies was ignored, but today it is clear that the phenotype of rodent models differs essentially in relation to the environment of origin, i.e. different breeders or different rooms. In this review, we outline the mechanisms behind gut bacterial impact on rodent models of immune mediated diseases, and how differences in environment of origin leads to phenotypic model differences within research areas such as infectious diseases and vaccine development, the metabolic syndrome, gut immunity and inflammation, autoimmunity and allergy. Finally, we sum up some tools to handle this impact to increase reproducibility and translatability of rodent models.

Clinical characteristics and outcome of hospitalized children and adolescent patients with type 1 diabetes during the COVID-19 pandemic: data from a single center surveillance study in Egypt

OBJECTIVES

COVID-19 pandemic significantly impacted the diagnosis of type 1 diabetes and its acute complications. Thus, the study aimed to evaluate the characteristics of pediatric patients with type 1 diabetes hospitalized during the first wave of the pandemic and the prevalence of new onset diabetes among patients with evidence of COVID-19 infection.

METHODS

A single-center surveillance study included all patients with diabetes admitted to Children's Hospital, Ain Shams University, in Egypt between May to August 2020. Data were collected to evaluate patients' clinical and laboratory characteristics as well as their outcomes.

RESULTS

Thirty-six patients were admitted during the study period. The mean age was 8.4 ± 3.8 years. Patients presented late to the emergency department with a mean delay of 3.05 ± 1.19 days from onset of symptoms. 34/36 patients presented in diabetic ketoacidosis (DKA), 50% presenting in severe DKA. Almost 81% of the patients were newly diagnosed. During the study period, SARS-CoV-2 PCR was found positive in four patients, COVID Ig M antibodies were positive in another two patients; all were symptomatic requiring ICU admission. Four patients showed a picture suggestive of the multi-inflammatory syndrome (MIS-C); cardiac affection was a constant feature.

CONCLUSIONS

The pandemic affected both the prevalence and severity of DKA among pediatric patients. The increased prevalence of severe DKA could be partly related to delayed hospital admission or the effect of COVID-19 in triggering DKA. Efforts should be done to continuously raise awareness about diabetes in children as well as the importance of seeking timely medical guidance.

Genetic architecture of type 1 diabetes with low genetic risk score informed by 41 unreported loci

Type 1 diabetes (T1D) patients with low genetic risk scores (GRS) may be non-autoimmune or autoimmune mediated by other genetic loci. The T1D-GRS2 provides us an opportunity to look into the genetic architecture of these patients. A total of 18,949 European individuals were included in this study, including 6599 T1D cases and 12,323 controls. 957 (14.5%) T1D patients were identified with low GRS (GRS < 8.43). The genome-wide association study on these patients identified 41 unreported loci. Two loci with common variants and 39 loci with rare variants were identified in this study. This study identified common SNPs associated with both low GRS T1D and expression levels of the interferon-α-induced MNDA gene, indicating the role of viral infection in T1D. Interestingly, 16 of the 41 unreported loci have been linked to autism spectrum disorder (ASD) by previous studies, suggesting that genes residing at these loci may underlie both T1D and autism.

Host miR-4301 promotes rotavirus replication via PPP1R3D in Caco-2 cells

To investigate the role of miR-4301 in rotavirus (RV)-infected Caco-2 cells. In this experiment, RNAs of RV-infected Caco-2 cells were extracted, and the high-throughput second-generation sequencing was performed to detect the expression profiles of host microRNAs (miRNAs). Synthetic miRNA mimics and inhibitors were examined (quantitative polymerase chain reaction [qPCR], crystalline violet, immunofluorescence and electron microscopy) to evaluate the effect on RV replication. Target genes of miR-4301 were predicted by software analysis. The expression of target genes was evaluated by qPCR and Western blot after transfected with miRNA inhibitor/mimic, and crystalline violet and qPCR were used to detect the downregulation effects of target genes on RV replication. By transfecting miRNA inhibitors/mimics and detecting downstream target genes, the mechanism of miRNA affecting RV replication was analyzed. There were 78 known miRNAs with significant differential expression, including 39 upregulated miRNAs and 39 downregulated miRNAs. The results showed that miR-4301 exerted a key role in enhancing RV replication. PPP1R3D protein which can inhibit RV replication was predicted as the target gene of miR-4301 by software analysis. While upregulating miR-4301 by RV, the expression of PPP1R3D and glycogen synthase (GS) is suppressed. For the first time, the effect of miR-4301 on RV infection, and its influence on GS was investigated. Specifically, RV inhibits host cell glycogen synthesis to utilize the host intracellular glucose for promoting its own replication.

Deficiency of the innate immune adaptor STING promotes autoreactive T cell expansion in NOD mice

AIMS/HYPOTHESIS

Stimulator of IFN genes (STING) is a central hub for cytosolic nucleic acid sensing and its activation results in upregulation of type I IFN production in innate immune cells. A type I IFN gene signature seen before the onset of type 1 diabetes has been suggested as a driver of disease initiation both in humans and in the NOD mouse model. A possible source of type I IFN is through activation of the STING pathway. Recent studies suggest that STING also has antiproliferative and proapoptotic functions in T cells that are independent of IFN. To investigate whether STING is involved in autoimmune diabetes, we examined the impact of genetic deletion of STING in NOD mice.

METHODS

CRISPR/Cas9 gene editing was used to generate STING-deficient NOD mice. Quantitative real-time PCR was used to assess the level of type I IFN-regulated genes in islets from wild-type and STING-deficient NOD mice. The number of islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)206-214-specific CD8+ T cells was determined by magnetic bead-based MHC tetramer enrichment and flow cytometry. The incidence of spontaneous diabetes and diabetes after adoptive transfer of T cells was determined.

RESULTS

STING deficiency partially attenuated the type I IFN gene signature in islets but did not suppress insulitis. STING-deficient NOD mice accumulated an increased number of IGRP206-214-specific CD8+ T cells (2878 ± 642 cells in NOD.STING-/- mice and 728.8 ± 196 cells in wild-type NOD mice) in peripheral lymphoid tissue, associated with a higher incidence of spontaneous diabetes (95.5% in NOD.STING-/- mice and 86.2% in wild-type NOD mice). Splenocytes from STING-deficient mice rapidly induced diabetes after adoptive transfer into irradiated NOD recipients (median survival 75 days for NOD recipients of NOD.STING-/- mouse splenocytes and 121 days for NOD recipients of NOD mouse splenocytes).

CONCLUSIONS/INTERPRETATION

Data suggest that sensing of endogenous nucleic acids through the STING pathway may be partially responsible for the type I IFN gene signature but not autoimmunity in NOD mice. Our results show that the STING pathway may play an unexpected intrinsic role in suppressing the number of diabetogenic T cells.

Molecular mimicry between varicella, measles virus and Hsp60 in type 1 diabetes associated HLA-DR3/DR4 molecules

BACKGROUND AND AIMS

Type 1 diabetes (T1D) is a multifactorial autoimmune disease that combines genetics and environmental factors. The aim of this study is to determine the environmental risk factors and to investigate how virals infections are risks factors for type 1 diabetics whom have HLA DR3/DR4 predisposition in our population.

METHODS

This study includes 233 subjects, 145 diabetics and 88 controls from regions of the extreme western of Algeria. All the informations related to the disease were collected using predesigned questionnaire. Using in silico approach, we attempt to improve the understanding of this analytical result by molecular mimicry, which is associated with the breakdown of several autoimmune pathologies.

RESULTS

The statistical study showed that history of varicella and measles infection and T1D related inheritance and type 2 diabetes are risk factors for T1D in the population of Tlemcen. We have determined the homologous antigenic regions between the glycoprotein "gE" of the varicella virus, the "hemagglutinin" of measles and the human protein "HSP60" at the level of their sequence and 3D structure. These cross-reactive epitopes bind to MHC class II molecules (HLA DR3/DR4) that predispose to T1D but not to MHC class II molecules (HLA DR2) that protect against T1D. This epitopes induce Th2 cells but only "hemagglutinin" and "Hsp60" can activate Th1 differentiation. This indicates their potential to destroy pancreatic cells β.

CONCLUSION

Our study can allow us to adapt biological markers to genetically predisposed T1D and to establish a preventive strategy for healthy genetic predisposed individuals in Tlemcen population.

Type 1 Diabetes: Interferons and the Aftermath of Pancreatic Beta-Cell Enteroviral Infection

Enteroviruses (EVs) have long been implicated in the pathogenesis of type 1 diabetes (T1D), and accumulating evidence has associated virus-induced autoimmunity with the loss of pancreatic beta cells in T1D. Inflammatory cytokines including interferons (IFN) form a primary line of defence against viral infections, and their chronic elevation is a hallmark feature of many autoimmune diseases. IFNs play a key role in activating and regulating innate and adaptive immune responses, and to do so they modulate the expression of networks of genes and transcription factors known generically as IFN stimulated genes (ISGs). ISGs in turn modulate critical cellular processes ranging from cellular metabolism and growth regulation to endoplasmic reticulum (ER) stress and apoptosis. More recent studies have revealed that IFNs also modulate gene expression at an epigenetic as well as post-transcriptional and post-translational levels. As such, IFNs form a key link connecting the various genetic, environmental and immunological factors involved in the initiation and progression of T1D. Therefore, gaining an improved understanding of the mechanisms by which IFNs modulate beta cell function and survival is crucial in explaining the pathogenesis of virally-induced T1D. This should provide the means to prevent, decelerate or even reverse beta cell impairment.

Extending the Enterovirus Lead: Could a Related Picornavirus be Responsible for Diabetes in Humans?

We found an association between the abundance of rodents in the wild and onset of type 1 diabetes (T1D) in humans. A picornavirus named Ljungan virus (LV) was subsequently isolated from wild bank voles. Both picornavirus-like particles detected by electron microscopy and LV antigen visualized by immunohistochemistry was seen in islets of Langerhans in diabetic wild bank voles. LV antigen has also been found in islets of Langerhans in a patient with recent onset of T1D and in the commonly used Bio Breeding (BB) T1D rat model. We discuss the possibility of T1D and type 2 diabetes (T2D) as parts of a single disease entity. Antiviral compounds directed against picornavirus have been found to be an effective treatment of diabetes in BB rats. We propose using the same currently available antiviral compounds in clinical trials in humans. Antiviral treatment would have the potential to be both proof of concept for involvement of a picornavirus in diabetes pathogenesis and also present a first-generation therapy.

Synthesis, molecular modeling and antiviral activity of novel 5-fluoro-1H-indole-2,3-dione 3-thiosemicarbazones

In this work, novel 5-fluoro-1-methyl/ethyl-1H-indole-2,3-dione 3-[4-(substituted phenyl)-thiosemicarbazones] 6a-n and 7a-n were synthesized. The antiviral effects of the compounds were tested against HSV-1 (KOS), HSV-2 (G) HSV-1 TK^- KOS ACV^r and VV in HEL cell cultures using acyclovir and ganciclovir as standards, and Coxsackie B4 virus in Vero cell cultures using ribavirin and mycophenolic acid as standards. R₂ ethyl substituted 7 derivatives were found effective against viruses tested. R₁ 4-CF₃ substituted 7d, R₁ 4-OCH₃ substituted 7 g and R₁ 3-Cl substituted 7 l showed activity against HSV-1 (KOS), HSV-2 (G) HSV-1 TK^- KOS ACV^r and VV. Whereas only R₁ 4-Br substituted 7n has selective activity against coxsackie B4 virus. Molecular modelingstudies of 7d and 7l were performed to determine binding side on HSV-1 glycoprotein B and D, HSV-2 glycoprotein B structures.

Effectiveness of Antivirals in a Type 1 Diabetes Model and the Move Toward Human Trials

A Picornavirus (Ljungan virus [LV]) originally found in bank voles has been associated with type 1 diabetes (T1D) in its wild rodent reservoir, but also associated with T1D in a laboratory rat model for the disease, the diabetes prone (DP) Bio Breeding (BB) rat. Successful treatment of diabetes in this rat model, using experimental antiviral compounds directed against picornavirus, has been reported. In the present study we show significant clinical response in DP-BB rats using antiviral compounds available for human use (Pleconaril, Efavirenz, and Ribavirin). Presence of LV picornavirus antigen has been detected in islets of Langerhans from both human and the T1D rat model with clear morphological similarity. Based on these data it would be of interest to test antiviral treatment in patients with newly diagnosed T1D. Successful outcome will offer both proof of concept regarding the role of virus involvement in the disease and possibly a first generation treatment interrupting a persistent infection and stopping β-cell destruction.

The Role of β Cell Stress and Neo-Epitopes in the Immunopathology of Type 1 Diabetes

Due to their secretory function, β cells are predisposed to higher levels of endoplasmic reticulum (ER) stress and greater sensitivity to inflammation than other cell types. These stresses elicit changes in β cells that alter their function and immunogenicity, including defective ribosomal initiation, post-translational modifications (PTMs) of endogenous β cell proteins, and alternative splicing. Multiple published reports confirm the presence of not only CD8+ T cells, but also autoreactive CD4+ T cells within pancreatic islets. Although the specificities of T cells that infiltrate human islets are incompletely characterized, they have been confirmed to include neo-epitopes that are formed through stress-related enzymatic modifications of β cell proteins. This article summarizes emerging knowledge about stress-induced changes in β cells and data supporting a role for neo-antigen formation and cross-talk between immune cells and β cells that provokes autoimmune attack - leading to a breakdown in tissue-specific tolerance in subjects who develop type 1 diabetes.

What the HLA-I!-Classical and Non-classical HLA Class I and Their Potential Roles in Type 1 Diabetes

PURPOSE OF REVIEW

Hyperexpression of classical HLA class I (HLA-I) molecules in insulin-containing islets has become a widely accepted hallmark of type 1 diabetes pathology. In comparison, relatively little is known about the expression, function and role of non-classical subtypes of HLA-I. This review focuses on the current understanding of the non-classical HLA-I subtypes: HLA-E, HLA-F and HLA-G, within and outside the field of type 1 diabetes, and considers the possible impacts of these molecules on disease etiology.

RECENT FINDINGS

Evidence is growing to suggest that non-classical HLA-I proteins are upregulated, both at the RNA and protein levels in the pancreas of individuals with recent-onset type 1 diabetes. Moreover, associations between non-classical HLA-I genotypes and age at onset of type 1 diabetes have been reported in some studies. As with classical HLA-I, it is likely that hyperexpression of non-classical HLA-I is driven by the release of diffusible interferons by stressed β cells (potentially driven by viral infection) and exacerbated by release of cytokines from infiltrating immune cells. Non-classical HLA-I proteins predominantly (but not exclusively) transduce negative signals to immune cells infiltrating at the site of injury/inflammation. We propose a model in which the islet endocrine cells, through expression of non-classical HLA-I are fighting back against the infiltrating immune cells. By inhibiting the activity and function on NK, B and select T cells, the non-classical HLA-I, proteins will reduce the non-specific bystander effects of inflammation, while at the same time still allowing the targeted destruction of β cells by specific islet-reactive CD8+ T cells.

Prospective virome analyses in young children at increased genetic risk for type 1 diabetes

Viruses are implicated in autoimmune destruction of pancreatic islet β cells, which results in insulin deficiency and type 1 diabetes (T1D)1-4. Certain enteroviruses can infect β cells in vitro5, have been detected in the pancreatic islets of patients with T1D6 and have shown an association with T1D in meta-analyses4. However, establishing consistency in findings across studies has proven difficult. Obstacles to convincingly linking RNA viruses to islet autoimmunity may be attributed to rapid viral mutation rates, the cyclical periodicity of viruses7 and the selection of variants with altered pathogenicity and ability to spread in populations. β cells strongly express cell-surface coxsackie and adenovirus receptor (CXADR) genes, which can facilitate enterovirus infection8. Studies of human pancreata and cultured islets have shown significant variation in enteroviral virulence to β cells between serotypes and within the same serotype9,10. In this large-scale study of known eukaryotic DNA and RNA viruses in stools from children, we evaluated fecally shed viruses in relation to islet autoimmunity and T1D. This study showed that prolonged enterovirus B rather than independent, short-duration enterovirus B infections may be involved in the development of islet autoimmunity, but not T1D, in some young children. Furthermore, we found that fewer early-life human mastadenovirus C infections, as well as CXADR rs6517774, independently correlated with islet autoimmunity.

Clinical Phenotypes of Severe Cutaneous Drug Hypersensitivity Reactions

Drug hypersensitivity reactions are clinically heterogenous ranging from mild to severe. Most drug hypersensitivity reactions are accompanied by cutaneous manifestations. Fever, mucous membrane involvement, large blisters, facial oedema, pustulosis and visceral involvement are clinical features that lead to suspicion of severe adverse drug reactions. Severe cutaneous adverse drug reactions (SCARs) include Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash eosinophilia and systemic symptoms, acute generalized exanthematous pustulosis. Serum sickness like reactions, drug induced vasculitis and generalized bullous fixed drug eruptions are less severe clinical entities. SCARs are uncommon but associated with significant morbidity and mortality. Physician should be aware of specific red flags and danger signs to immediately identify these reactions. Immediate drug withdrawal is mandatory. Early diagnosis and appropriate treatment significantly affect the prognosis of the disease. The purpose of our review is to discuss clinical phenotypes of severe cutaneous drug hypersensitivity reactions.

N-Acetyl-l-Cysteine Supplement in Early Life or Adulthood Reduces Progression of Diabetes in Nonobese Diabetic Mice

BACKGROUND

Oxidative stress contributes to the pathologic process leading to the development, progression, and complications of type 1 diabetes (T1D).

OBJECTIVE

The aim of this study was to investigate the effect of the antioxidant N-acetyl-l-cysteine (NAC), supplemented during early life or adulthood on the development of T1D.

METHODS

NAC was administered to nonobese diabetic (NOD) female mice during pregnancy and lactation, and the development of diabetes was followed in offspring. In an additional set of experiments, offspring of untreated mice were given NAC during adulthood, and the development of T1D was followed. Morbidity rate, insulitis and serum cytokines were measured in the 2 sets of experiments. In addition, markers of oxidative stress, glutathione, lipid peroxidation, total antioxidant capacity and activity of antioxidant enzymes, were followed.

RESULTS

Morbidity rate was reduced in both treatment protocols. A decrease in interferon γ, tumor necrosis factor α, interleukin 1α, and other type 1 diabetes-associated proinflammatory cytokines was found in mice supplemented with NAC in adulthood or during early life compared with control NOD mice. The severity of insulitis was higher in control NOD mice than in treated groups. NAC administration significantly reduced oxidative stress, as determined by reduced lipid peroxidation and increased total antioxidant capacity in serum and pancreas of mice treated in early life or in adulthood and increased pancreatic glutathione when administrated in adulthood. The activity of antioxidant enzymes was not affected in mice given NAC in adulthood, whereas an increase in the activity of superoxide dismutase and catalase was demonstrated in the pancreas of their offspring.

CONCLUSION

NAC decreased morbidity of NOD mice by attenuating the immune response, presumably by eliminating oxidative stress, and might be beneficial in reducing morbidity rates of T1D in high-risk individuals.

Understanding the manifestation of diabetes in sub Saharan Africa to inform therapeutic approaches and preventive strategies: a narrative review

BACKGROUND

Globally, the burden of diabetes mellitus has increased to epidemic proportions. Estimates from the International Diabetes Federation predict that the greatest future increase in the prevalence of diabetes mellitus will occur in Africa.

METHODS

This article reviews literature on the manifestation of diabetes in adult patients in sub-Saharan Africa highlighting the distinct phenotypes, plausible explanations for this unique manifestation and the clinical significance of comprehensively defining and understanding the African diabetes phenotype.

RESULTS

There are few studies on the manifestation or phenotype of diabetes in Africa. The limited data available suggests that, compared to the Western world, the majority of patients with diabetes in Africa are young and relatively lean in body size. In addition, hyperglycaemia in most cases is characterised by a significantly blunted acute first phase of insulin secretion in response to an oral or intravenous glucose load and pancreatic beta cell secretory dysfunction, rather than peripheral insulin resistance predominates. Genetic and environmental factors like chronic infections/inflammation, early life malnutrition and epigenetic modifications are thought to contribute to these distinct differences in manifestation.

CONCLUSIONS

While published data is limited, there appears to be distinct phenotypes of diabetes in sub-Saharan Africa. Large and more detailed studies are needed especially among newly diagnosed patients to fully characterize diabetes in this region. This will further improve the understanding of manifestation of diabetes and guide the formulation of optimal therapeutic approaches and preventive strategies of the condition on the continent.

Rotavirus infection beyond the gut

The landscape of rotavirus (RV) infection has changed substantially in recent years. Autoimmune triggering has been added to clinical spectrum of this pathology, which is now known to be much broader than diarrhea. The impact of RV vaccines in these other conditions is becoming a growing field of research. The importance of host genetic background in RV susceptibility has been revealed, therefore increasing our understanding of vaccine effectiveness and giving some clues about the limited efficacy of RV vaccines in low-income settings. Also, interaction of RV with intestinal microbiota seems to play a key role in the process of infection vaccine effect. This article reviews current findings on the extraintestinal impact of RV infection and their widening clinical picture, and the recently described mechanisms of host susceptibility to infection and vaccine effectiveness. RV infection is a systemic disease with clinical and pathophysiological implications beyond the gut. We propose an “iceberg” model for this pathology with almost hidden clinical implications away from the gastrointestinal tract and eventually triggering the development of autoimmune diseases. Impact of current vaccines is being influenced by host genetics and gut microbiota interactions and these factors must be taken into account in the development of public health programs.

Study of 2009 H1N1 Pandemic Influenza Virus as a Possible Causative Agent of Diabetes

CONTEXT

Recent studies have suggested that influenza A virus (IAV) might be involved in the etiology of diabetes.

OBJECTIVE AND METHODS

To address this question, we tested the ability of H1N1 pandemic IAV to infect, replicate, and damage human β cells/pancreatic islets in vitro and induce pancreatic damage and/or glucose metabolism alterations in chemical and autoimmune models of β cell damage in vivo. Moreover, we looked for direct and/or indirect evidence of correlation between IAV infection and autoimmunity/diabetes in humans.

RESULTS

Human H1N1 A/California/2009-derived viruses infected human pancreatic islets in vitro, inducing a proinflammatory response associated with substantial increases of CXCL9 and CXCL10 release. In vivo, infected mice showed a clear susceptibility to the virus, with its localization also found in extrapulmonary organs, including the pancreas. Infection was able to induce mild modifications of glycemia in C57B6 mice after chemical damage of islets but did not modulate the autoimmune damage of islets in NOD mice. One of 69 nasopharyngeal swabs collected from patients at the onset of type 1 diabetes yielded positive results for IAV. Pancreas sections from 17 organ donors available from the Network for Pancreatic Organ Donors With Diabetes showed the persistence of CXCL10-positive cells in islet autoimmunity-positive subjects; however, extremely rare cells stained for viral RNA and not preferentially in autoimmune subjects.

CONCLUSION

Influenza H1N1 pdm strains are able to infect and replicate in mammalian pancreatic cells both in vitro and in vivo but did not cause any functional impairment consistent with diabetes.

Inverse relationship between serum vitamin D level and measles antibody titer: A cross-sectional analysis of NHANES, 2001-2004

Background

In recent years, researchers have illuminated many non-skeletal actions of vitamin D including host defense against various pathogens and vaccine immunology. The purpose of our study was to explore the potential association between serum vitamin D levels and measles antibody titers.

Methods

The biochemical profiles and de-identified information were accessed from the 2001 to 2004 National Health and Nutrition Examination Survey (NHANES). Participants were divided into quartiles according to their measles antibody titers.

Results

A total of 5,681 participants were analyzed in our study. Participants in the highest quartile of measles antibody titer had significantly lower serological levels of 25-hydroxyvitamin D [25(OH)D] than those in the lower quartiles (53.90 vs. 58.70 nmol/L, a decrease of 8.18%) (p < 0.001). After full adjustment of confounders, the adjusted ß coefficient of 25(OH)D was -0.006 (p<0.001). A decreasing tendency of 25(OH)D among quartiles of measles antibody titers was obvious (p for trend <0.001). The negative association in seropositive subjects remained statistically significant only in non-Hispanic black population before adjustment for age, gender, and other covariates (p<0.05).

Conclusion

Our study highlights the negative association between serum 25(OH)D levels and measles antibody titers.

Management of Diabetes in Children and Adolescents

Diabetes is a common chronic illness in children and adolescents. This article will discuss the prevalence, diagnostic criteria, types, treatment, and transition of care into adulthood.

The innate immune receptor MDA5 limits rotavirus infection but promotes cell death and pancreatic inflammation

Melanoma differentiation-associated protein 5 (MDA5) mediates the innate immune response to viral infection. Polymorphisms in IFIH1, the gene coding for MDA5, correlate with the risk of developing type 1 diabetes (T1D). Here, we demonstrate that MDA5 is crucial for the immune response to enteric rotavirus infection, a proposed etiological agent for T1D. MDA5 variants encoded by minor IFIH1 alleles associated with lower T1D risk exhibit reduced activity against rotavirus infection. We find that MDA5 activity limits rotavirus infection not only through the induction of antiviral interferons and pro-inflammatory cytokines, but also by promoting cell death. Importantly, this MDA5-dependent antiviral response is specific to the pancreas of rotavirus-infected mice, similar to the autoimmunity associated with T1D. These findings imply that MDA5-induced cell death and inflammation in the pancreas facilitate progression to autoimmune destruction of pancreatic β-cells.

Innate Viral Receptor Signaling Determines Type 1 Diabetes Onset

Heritable susceptibility of the autoimmune disorder, type 1 diabetes (T1D), only partially equates for the incidence of the disease. Significant evidence attributes several environmental stressors, such as vitamin D deficiency, gut microbiome, dietary antigens, and most notably virus infections in triggering the onset of T1D in these genetically susceptible individuals. Extensive epidemiological and clinical studies have provided credibility to this causal relationship. Infection by the enterovirus, coxsackievirus B, has been closely associated with onset of T1D and is considered a significant etiological agent for disease induction. Recognition of viral antigens via innate pathogen-recognition receptors induce inflammatory events which contribute to autoreactivity of pancreatic self-antigens and ultimately the destruction of insulin-secreting beta cells. The activation of these specific innate pathways and expression of inflammatory molecules, including type I and III interferon, prime the immune system to elicit either a protective regulatory response or a diabetogenic effector response. Therefore, sensing of viral antigens by retinoic acid-inducible gene I-like receptors and toll-like receptors may be detrimental to inducing autoreactivity initiated by viral stress and resulting in T1D.

Viral infection causes a shift in the self peptide repertoire presented by human MHC class I molecules

PURPOSE

MHC class I presentation of peptides allows T cells to survey the cytoplasmic protein milieu of host cells. During infection, presentation of self peptides is, in part, replaced by presentation of microbial peptides. However, little is known about the self peptides presented during infection, despite the fact that microbial infections alter host cell gene expression patterns and protein metabolism.

EXPERIMENTAL DESIGN

The self peptide repertoire presented by HLA-A*01;01, HLA-A*02;01, HLA-B*07;02, HLA-B*35;01, and HLA-B*45;01 (where HLA is human leukocyte antigen) was determined by tandem MS before and after vaccinia virus infection.

RESULTS

We observed a profound alteration in the self peptide repertoire with hundreds of self peptides uniquely presented after infection for which we have coined the term "self peptidome shift." The fraction of novel self peptides presented following infection varied for different HLA class I molecules. A large part (approximately 40%) of the self peptidome shift arose from peptides derived from type I interferon-inducible genes, consistent with cellular responses to viral infection. Interestingly, approximately 12% of self peptides presented after infection showed allelic variation when searched against approximately 300 human genomes.

CONCLUSION AND CLINICAL RELEVANCE

Self peptidome shift in a clinical transplant setting could result in alloreactivity by presenting new self peptides in the context of infection-induced inflammation.

Systematic review and meta-analysis of the association between mumps during childhood and risk of type 1 diabetes mellitus

We conducted a systematic review and meta-analysis of the association between mumps and risk of type 1 diabetes mellitus (T1DM). Literature searches were conducted using Medline, EMBASE and Web of Science including studies published before February 2014. Crude and, where available, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were extracted from the published reports of each included study. Combined OR estimates and tests of heterogeneity were obtained using meta-analysis techniques. The analysis was repeated in subgroups of studies on the basis of quality defined by the score on the Newcastle-Ottawa scale (NOS). In total, 18 articles met the eligibility criteria, and overall there was some evidence of a weak association between clinically diagnosed mumps and T1DM (OR=1.23, 95% CI 1.00-1.51; p=0.05) but marked heterogeneity between studies (I2=49%; p for heterogeneity=0.01). Restricting analyses to 13 high quality studies, there was little evidence of association between clinically diagnosed mumps and T1DM (OR=1.11, 95% CI 0.91-1.35; p=0.29) and there was much less heterogeneity (I2=26%; p for heterogeneity=0.18). Overall there was little evidence of any strong association between mumps infection and T1DM.

Diabetic Cardiomyopathy: A Forensic Perspective

Diabetes mellitus is a common condition affecting both adults and children. Long-standing diabetes is associated with cardiovascular abnormalities such as coronary artery atherosclerosis, microvascular changes, hypertension, kidney disease, and heart failure. Its association with heart failure in the absence of coronary artery disease and hypertension was termed diabetic cardiomyopathy in the 1970s and is believed to account for some of the cardiac mortality in diabetic patients. This entity may be implicated as the cause of sudden cardiac death in the small percentage of diabetic patients in which the autopsy fails to demonstrate evidence of nonketotic hyperosmolar coma, diabetic ketoacidosis, or atherosclerotic and hypertensive cardiovascular disease. Molecular and metabolic alterations have been studied to explain the pathophysiology of this disease.

Common mechanisms involved in Alzheimer's disease and type 2 diabetes: a key role of chronic bacterial infection and inflammation

Strong epidemiologic evidence and common molecular mechanisms support an association between Alzheimer's disease (AD) and type 2-diabetes. Local inflammation and amyloidosis occur in both diseases and are associated with periodontitis and various infectious agents. This article reviews the evidence for the presence of local inflammation and bacteria in type 2 diabetes and discusses host pathogen interactions in chronic inflammatory disorders. Chlamydophyla pneumoniae, Helicobacter pylori and spirochetes are demonstrated in association with dementia and brain lesions in AD and islet lesions in type 2 diabetes. The presence of pathogens in host tissues activates immune responses through Toll-like receptor signaling pathways. Evasion of pathogens from complement-mediated attack results in persistent infection, inflammation and amyloidosis. Amyloid beta and the pancreatic amyloid called amylin bind to lipid bilayers and produce Ca(2+) influx and bacteriolysis. Similarly to AD, accumulation of amylin deposits in type 2 diabetes may result from an innate immune response to chronic bacterial infections, which are known to be associated with amyloidosis. Further research based on an infectious origin of both AD and type 2 diabetes may lead to novel treatment strategies.

Luminex and other multiplex high throughput technologies for the identification of, and host response to, environmental triggers of type 1 diabetes

Complex interactions between a series of environmental factors and genes result in progression to clinical type 1 diabetes in genetically susceptible individuals. Despite several decades of research in the area, these interactions remain poorly understood. Several studies have yielded associations of certain foods, infections, and immunizations with the onset and progression of diabetes autoimmunity, but most findings are still inconclusive. Environmental triggers are difficult to identify mainly due to (i) large number and complex nature of environmental exposures, including bacteria, viruses, dietary factors, and environmental pollutants, (ii) reliance on low throughput technology, (iii) less efforts in quantifying host response, (iv) long silent period between the exposure and clinical onset of T1D which may lead to loss of the exposure fingerprints, and (v) limited sample sets. Recent development in multiplex technologies has enabled systematic evaluation of different classes of molecules or macroparticles in a high throughput manner. However, the use of multiplex assays in type 1 diabetes research is limited to cytokine assays. In this review, we will discuss the potential use of multiplex high throughput technologies in identification of environmental triggers and host response in type 1 diabetes.

The Role of Human Herpesvirus 8 in Diabetes Mellitus Type 2: State of the Art and a Medical Hypothesis

Diabetes is a common chronic disease due to an altered glucose metabolism, caused by the quantitative and/or qualitative dysfunction of the insulin hormone. Two types of diabetes are recognized: juvenile diabetes, or type 1, which has an autoimmune origin, and adult diabetes, or type 2 (DMT2), which covers 90-95 % of all diabetic patients.The causes of DMT2 are not yet clear: heredity, life style, nutrition, and environment are considered the main risk factors. Several viral infections, namely cytomegalovirus, coxsackie and other enteroviruses, rubella and hepatitis C virus, have been claimed to be associated with some forms of diabetes. The direct role of viruses as a cause or as a risk of type 1 diabetes has been amply described in several recent reviews. Therefore, this review focuses attention on the role of a human herpes pathogenic virus in the onset of DMT2. By carrying out an analysis of recent literature, we describe the findings reported on an extremely deceitful virus, such as Human Herpes virus 8, and present a medical hypothesis on a possible relationship between this virus and DMT2.

Regulatory T cells resist virus infection-induced apoptosis

Regulatory T (Treg) cells are important in the maintenance of self-tolerance, and the depletion of Treg cells correlates with autoimmune development. It has been shown that type I interferon (IFN) responses induced early in the infection of mice can drive memory (CD44hi) CD8 and CD4 T cells into apoptosis, and we questioned here whether the apoptosis of CD44-expressing Treg cells might be involved in the infection-associated autoimmune development. Instead, we found that Treg cells were much more resistant to apoptosis than CD44hi CD8 and CD4 T cells at days 2 to 3 after lymphocytic choriomeningitis virus infection, when type I IFN levels are high. The infection caused a downregulation of the interleukin-7 (IL-7) receptor, needed for survival of conventional T cells, while increasing on Treg cells the expression of the high-affinity IL-2 receptor, needed for STAT5-dependent survival of Treg cells. The stably maintained Treg cells early during infection may explain the relatively low incidence of autoimmune manifestations among infected patients.

IMPORTANCE

Autoimmune diseases are controlled in part by regulatory T cells (Treg) and are thought to sometimes be initiated by viral infections. We tested the hypothesis that Treg may die off at early stages of infection, when virus-induced factors kill other lymphocyte types. Instead, we found that Treg resisted this cell death, perhaps reducing the tendency of viral infections to cause immune dysfunction and induce autoimmunity.