Altered natural killer (NK) cell frequency and phenotype in latent autoimmune diabetes in adults (LADA) prior to insulin deficiency

Changes of B cell subsets in different types of diabetes and its effect on the progression of latent autoimmune diabetes in adults

PURPOSE

Developmental abnormalities in B cells is one of the key players in autoimmune diabetes, but little is known about its role in latent autoimmune diabetes in adults (LADA). This study aimed to investigate the distribution of B cell subsets in different types of diabetes and to analyze their correlations with other biochemical parameters.

METHODS

A total of 140 participants were prospectively enrolled from January 2021 to December 2022. Diabetes-related autoantibodies and laboratory indicators were tested. Flow cytometry was used to analyze the percentage of circulating B cell subsets and T follicular cells. The correlation of B cell subsets with different indicators was assessed by Spearman's correlation method.

RESULTS

We observed that the Naïve phenotype cells tended to be less frequent in patients with diabetes than in healthy controls. The frequency of plasmablasts (PB) and Breg cell-related phenotype (B10) were significantly higher in LADA. Notably, the percentage of PB was positively associated with levels of islet cell antibody (ICA) and insulin autoantibody (IAA), but inversely associated with fasting C-peptide (FCP), further indicating that PB may promote the destruction of β-cell in patients with diabetes.

CONCLUSIONS

This study showed that patients with LADA had significantly altered frequencies of B cell subsets, particularly in the naïve to memory B cell ratio. Our study provided valuable information on the distribution characteristics of B cell subsets in LADA and suggested the feasibility of B-cell targeted therapy in LADA patients.

NK cells vs. obesity: A tale of dysfunction & redemption

Natural killer (NK) cells are critical in protecting the body against infection and cancer. NK cells can rapidly respond to these threats by directly targeting the infected or transformed cell using their cytotoxic machinery or by initiating and amplifying the immune response via their production of cytokines. Additionally, NK cells are resident across many tissues including adipose, were their role extends from host protection to tissue homeostasis. Adipose resident NK cells can control macrophage polarization via cytokine production, whilst also regulating stressed adipocyte fate using their cytotoxic machinery. Obesity is strongly associated with increased rates of cancer and a heightened susceptibility to severe infections. This is in part due to significant obesity-related immune dysregulation, including defects in both peripheral and adipose tissue NK cells. In this review, we detail the literature to date on NK cells in the setting of obesity - outlining the consequences, mechanisms and therapeutic interventions.

Association between a high triglyceride-glucose index and chronic kidney disease in adult patients with latent autoimmune diabetes

BACKGROUND

Insulin resistance (IR) is one of the risk factors for chronic kidney disease (CKD) and diabetes. The triglyceride-glucose (TyG) index is considered a reliable alternative marker of IR. We investigated the correlation between the TyG index and the severity of CKD in patients with latent autoimmune diabetes in adults (LADA).

METHODS

This cross-sectional study included 288 patients with LADA in the department of endocrinology at our hospital between January 2018 and January 2022. The TyG index was calculated as Ln [TG (mg/dl) × fasting blood glucose (FBG) (mg/dl) / 2]. All individuals were divided into either a LADA + CKD group or a LADA + non-CKD group according to the presence or absence of CKD. A correlation analysis, logistic regression analysis and receiver operating characteristics curve analysis were performed.

RESULTS

A total of 130 (45.1%) participants were identified as having CKD. Compared with the non-CKD group, the CKD group had a longer disease duration and a higher proportion of smokers; patients were more likely to have hypertension and higher serum creatinine, triglyceride, cholesterol, low-density lipoprotein cholesterol, FBG, uric acid estimated glomerular filtration rates (eGFR) and TyG levels as well as lower high-density lipoprotein cholesterol levels (all P < 0.05). The positive relationship between the TyG index and the urinary albumin/creatinine ratio was significant (r = 0.249, P = 0.010). There was also a significant correlation between the TyG index and the eGFR (r = - 0.211, P = 0.034) after adjusting for confounding factors. The area-under-the-curve value of the TyG index was 0.708 (95% confidence interval: 0.61-0.81, P < 0.001).

CONCLUSIONS

The TyG index is significantly associated with the severity of CKD in patients with LADA. This conclusion supports the clinical application of the TyG index for the assessment of kidney disease in patients with LADA.

Newly diagnosed type 1 diabetes mellitus in a human immunodeficiency virus-infected patient with antiretroviral therapy-induced immune reconstitution inflammatory syndrome: a case report

BACKGROUND

Diabetes that develops in human immunodeficiency virus (HIV)-infected patients who receive antiretroviral therapy (ART) is usually type 2 diabetes mellitus (T2DM); however, autoimmune diabetes, such as type 1 diabetes mellitus (T1DM) can also develop in this population. After treatment with ART, patients might experience clinical deterioration following an increase in the CD4 cell count, which is termed immune reconstitution inflammatory syndrome (IRIS). Here, we describe an HIV-infected patient on ART who developed T1DMat due to IRIS, highlighting the clinical complexity in diagnosis and treatment.

CASE PRESENTATION

A 36-year-old man infected with HIV had a nadir CD4 cell count of 15.53/μL before medication, which increased to 429.09/μL after 9 months of regular ART. The fasting serum glucose at 9 months was between 96 mg/dL and 117 mg/dL. After 11 months of ART, the patient was admitted to hospital for diabetic ketoacidosis (DKA) and Graves' disease (GD). Noninsulin antidiabetics (NIADs) were prescribed following the resolution of DKA. However, poor glycemic control was noted despite well-titrated NIADs. Further investigation demonstrated poor pancreatic beta cell function and elevated anti-glutamic acid decarboxylase (anti-GAD) and anti-tyrosine phosphatase-like insulinoma antigen 2 (anti-IA2) titers. According to the results, he was diagnosed with T1DM and received multiple daily injections(MDI) of insulin. The regimen of MDI was insulin degludec as basal insulin and insulin aspart as prandial insulin. After MDI therapy, his glycemic control was improved.

CONCLUSION

In this case, T1DM was ascribed to IRIS. Although this phenomenon has been demonstrated in previous case reports, further study is necessary to realize the mechanism of this association. Therefore, we emphasize that when HIV-infected patients on ART experience an unstable blood glucose level and abnormal thyroid function, physicians should consider T1DM and GD associated with ART-induced IRIS to reduce the subsequent complications and more serious endocrine dysfunction.

Association of immune cell composition with the risk factors and incidence of acute coronary syndrome

BACKGROUND

Although immune cells are involved in acute coronary syndrome (ACS), few studies have explored the association of incident ACS with the relative immune cell proportions. We aimed to investigate the association of immune cell proportions with the incidence and risk factors of ACS in the Dongfeng-Tongji cohort.

METHODS

We conducted the analyses with 38,295 subjects from the first follow-up of the Dongfeng-Tongji cohort, including DNA methylation profiles for 1570 individuals. The proportions of immune cell types were observed from routine blood tests or estimated from DNA methylation profiles. For both observed and estimated immune cell proportions, we tested their associations with risk factors of ACS by multivariable linear regression models. In addition, the association of each immune cell proportion with incident ACS was assessed by the Cox regression model and conditional logistic regression model, respectively, adjusting for the risk factors of ACS.

FINDINGS

The proportions of lymphocytes, monocytes, and neutrophils showed strong associations with sex, followed by diabetes. Moreover, sex and current smoking were the two factors with strongest association with the proportions of lymphocyte subtypes. The hazard ratio (HR) and 95% confidence interval (CI) of incident ACS per standard deviation (SD) increase in proportions of lymphocytes and neutrophils were 0.91 (0.85-0.96) and 1.10 (1.03-1.16), respectively. Furthermore, the OR (95% CI) of incident ACS per SD increase in proportions of NK cells, CD4⁺ T cells, and B cells were 0.88 (0.78-0.99), 1.15 (1.03-1.30), and 1.13 (1.00-1.26), respectively.

INTERPRETATION

The proportions of immune cells were associated with several risk factors of ACS, including sex, diabetes, and current smoking. In addition, proportion of neutrophils had a risk effect, while proportion of lymphocytes had a protective effect on the incidence of ACS. The protective effect of lymphocytes was probably driven by NK cells.

Latent autoimmune diabetes in adults in China

Latent autoimmune diabetes in adults (LADA) is a type of diabetes caused by slow progression of autoimmune damage to pancreatic beta cells. According to the etiological classification, LADA should belong to the autoimmune subtype of type 1 diabetes (T1D). Previous studies have found general immune genetic effects associated with LADA, but there are also some racial differences. Multicenter studies have been conducted in different countries worldwide, but it is still unclear how the Chinese and Caucasian populations differ. The epidemiology and phenotypic characteristics of LADA may vary between Caucasian and Chinese diabetic patients as lifestyle, food habits, and body mass index differ between these two populations. The prevalence of LADA in China has reached a high level compared to other countries. The prevalence of LADA in China has reached a high level compared to other countries, and the number of patients with LADA ranks first in the world. Previous studies have found general immune genetic effects associated with LADA, but some racial differences also exist. The prevalence of LADA among newly diagnosed type 2 diabetes patients over the age of 30 years in China is 5.9%, and LADA patients account for 65% of the newly diagnosed T1D patients in the country. As a country with a large population, China has many people with LADA. A summary and analysis of these studies will enhance further understanding of LADA in China. In addition, comparing the similarities and differences between the Chinese and the Caucasian population from the perspectives of epidemiology, clinical, immunology and genetics will help to improve the understanding of LADA, and then promote LADA studies in individual populations.

Expression of Caspase-3 in Circulating Innate Lymphoid Cells Subtypes Is Altered by Treatment with Metformin and Fluvastatin in High-Fat Diet Fed C57BL/6 Mice

The current study aimed to determine the expression levels of caspase-3 in circulating innate lymphoid cell subtypes (ILCs) in a high-fat diet (HFD)-induced prediabetes mouse model. Another critical point was to assess the therapeutic effects of metformin and fluvastatin in modulating caspase-3 activation in ILCs within these HFD-fed mice. Prominent results showed that mice exposed to HFD for 14 weeks displayed impaired glucose tolerance that was accompanied by elevated levels of low-density lipoprotein cholesterol (LDL-c) and altered haematological profile as characterised by significantly increased concentrations of red blood cell count, white cell count and lymphocytes when compared to those fed a low-fat diet (LFD). Moreover, the expression of caspase-3 in ILC1 and ILC3 was significantly increased in the HFD groups in comparison to the LFD-fed group. Notably, six-week treatment with metformin and fluvastatin reduced the caspase-3 activation in ILC subtypes. The reduced caspase-3 activation in ILC1 was inversely associated with HDL-c levels following metformin treatment. Interestingly, the reduced caspase-3 activation in ILC3 was associated with lower total cholesterol following fluvastatin treatment in these HFD-fed mice. However, there were no differences in activation of caspase-3 on ILC2 or any association between caspase-3 activation and changes in body weight or fasting blood glucose. Thus, while HFD-feeding clearly modulates ILCs, potentially leading to pro-apoptotic mechanisms, metformin and fluvastatin may play a major role in protecting against such metabolic disturbances.

Latent Autoimmune Diabetes in Adults (LADA): From Immunopathogenesis to Immunotherapy

Latent autoimmune diabetes in adults (LADA) is a type of diabetes characterized by slow autoimmune damage of pancreatic β cells without insulin treatment in the early clinical stage. There are differences between LADA and classical type 1 diabetes (T1D) and type 2 diabetes (T2D) in genetic background, autoimmune response, rate of islet function decline, clinical metabolic characteristics, and so on. The disease progression and drug response of patients with LADA are closely related to the level of islet autoimmunity, thus exploring the pathogenesis of LADA is of great significance for its prevention and treatment. Previous studies reported that adaptive immunity and innate immunity play a critical role in the etiology of LADA. Recent studies have shown that the intestinal microbiota which impacts host immunity hugely, participates in the pathogenesis of LADA. In addition, the progression of autoimmune pancreatic β cell destruction in LADA is slower than in classical T1D, providing a wider window of opportunities for intervention. Therefore, therapies including antidiabetic drugs with immune-regulation effects and immunomodulators could contribute to promising interventions for LADA. We also shed light on potential interventions targeting the gut microbiota and gut-associated immunity, which may be envisaged to halt or delay the process of autoimmunity in LADA.

Latent autoimmune diabetes in adults: a focus on β-cell protection and therapy

Latent autoimmune diabetes in adults (LADA) is a heterogeneous disease sharing some phenotypic, genetic, and immunological features with both type 1 and 2 diabetes. Patients with LADA have a relatively slow autoimmune process and more residual islet β-cell function at onset, allowing a time window to protect residual islet β cells and delay or inhibit disease progression. It is crucial to discover various heterogeneous factors affecting islet β-cell function for precise LADA therapy. In this review, we first describe the natural history of LADA. Thereafter, we summarize β-cell function-related heterogeneous factors in LADA, including the age of onset, body mass index, genetic background, and immune, lifestyle, and environmental factors. In parallel, we evaluate the impact of current hypoglycemic agents and immune intervention therapies for islet β-cell protection. Finally, we discuss the opportunities and challenges of LADA treatment from the perspective of islet β-cell function protection.

Innate immunity in latent autoimmune diabetes in adults

Latent autoimmune diabetes in adults (LADA) is an autoimmune disease that shares some genetic, immunological and clinical features with both type 1 diabetes and type 2 diabetes. Immune cells including CD4⁺ T cells, CD8⁺ T cells, B cells, macrophages and dendritic cells (DCs) have been detected in the pancreas of patients with LADA and a rat model of LADA. Therefore, similar to type 1 diabetes, the pathogenesis of LADA may be caused by interactions between islet β-cells and innate and adaptive immune cells. However, the role of the immunity in the initiation and progression of LADA remains largely unknown. In this review, we have summarized the potential roles of innate immunity and immune-modulators in LADA development. Furthermore, we have examined the evidence and discussed potential innate immunological reasons for the slower development of LADA compared with type 1 diabetes. More in-depth mechanistic studies are needed to fully elucidate the roles of innate immune-associated genes, molecules and cells in their contributions to LADA pathogenesis. Undertaking these studies will greatly enhance the development of new strategies and optimization of current strategies for the diagnosis and treatment of the disease.

Natural Killer Cells as Key Mediators in Type I Diabetes Immunopathology

The immunopathology of type I diabetes (T1D) presents a complicated case in part because of the multifactorial origin of this disease. Typically, T1D is thought to occur as a result of autoimmunity toward islets of Langerhans, resulting in the destruction of insulin-producing cells (β cells) and thus lifelong reliance on exogenous insulin. However, that explanation obscures much of the underlying mechanism, and the actual precipitating events along with the associated actors (latent viral infection, diverse immune cell types and their roles) are not completely understood. Notably, there is a malfunctioning in the regulation of cytotoxic CD8+ T cells that target endocrine cells through antigen-mediated attack. Further examination has revealed the likelihood of an imbalance in distinct subpopulations of tolerogenic and cytotoxic natural killer (NK) cells that may be the catalyst of adaptive immune system malfunction. The contributions of components outside the immune system, including environmental factors such as chronic viral infection also need more consideration, and much of the recent literature investigating the origins of this disease have focused on these factors. In this review, the details of the immunopathology of T1D regarding NK cell disfunction is discussed, along with how those mechanisms stand within the context of general autoimmune disorders. Finally, the rarer cases of latent autoimmune, COVID-19 (viral), and immune checkpoint inhibitor (ICI) induced diabetes are discussed as their exceptional pathology offers insight into the evolution of the disease as a whole.

NK Cells in Autoimmune Diseases: Protective or Pathogenic?

Autoimmune diseases generally result from the loss of self-tolerance (i.e., failure of the immune system to distinguish self from non-self), and are characterized by autoantibody production and hyperactivation of T cells, which leads to damage of specific or multiple organs. Thus, autoimmune diseases can be classified as organ-specific or systemic. Genetic and environmental factors contribute to the development of autoimmunity. Recent studies have demonstrated the contribution of innate immunity to the onset of autoimmune diseases. Natural killer (NK) cells, which are key components of the innate immune system, have been implicated in the development of multiple autoimmune diseases such as systemic lupus erythematosus, type I diabetes mellitus, and autoimmune liver disease. However, NK cells have both protective and pathogenic roles in autoimmunity depending on the NK cell subset, microenvironment, and disease type or stage. In this work, we review the current knowledge of the varied roles of NK cell subsets in systemic and organic-specific autoimmune diseases and their clinical potential as therapeutic targets.

Comprehensive Analyses of Type 1 Diabetes Ketosis- or Ketoacidosis-Related Genes in Activated CD56+CD16+ NK Cells

OBJECTIVES

Alterations in natural killer (NK) cells activity cause damage to pancreatic islets in type 1 diabetes mellitus (T1DM). The aim of this study is to identify T1DM ketosis- or ketoacidosis-related genes in activated CD56⁺CD16⁺ NK cells.

METHODS

Microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using the GEO2R tool. Enrichment analyses were performed using Metascape online database and GSEA software. Cell-specific gene co-expression network was built using NetworkAnalyst tools. Cytoscape software was used to identify hub genes and construct co-expressed networks. Target miRNAs were predicted based on the DIANA-micro T, miRDB, and miRWalk online databases.

RESULTS

A total of 70 DEGs were identified between T1DM patients recovered from ketosis or ketoacidosis and healthy control blood samples in GSE44314. Among the DEGs, 10 hub genes were screened out. The mature NK cell-specific gene co-expression network for DEGs in T1DM was built using NetworkAnalyst tools. DEGs between activated CD56⁺CD16⁺ NK cells and CD56^brightCD16^- NK cells were identified from GSE1511. After intersection, 13 overlapping genes between GSE44314 and GSE1511 microarray datasets were screened out, in which 7 hub genes were identified. Additionally, 59 target miRNAs were predicted according to the 7 hub genes. After validating with the exosome miRNA expression profile dataset of GSE97123, seven differentially expressed miRNAs (DEmiRNAs) in plasma-derived exosome were selected. Finally, a mRNA-miRNA network was constructed, which was involved in the T1DM ketosis or ketoacidosis process.

CONCLUSION

This work identified seven hub genes in activated CD56⁺CD16⁺ NK cells and seven miRNAs in plasma-derived exosome as potential predictors of T1DM ketoacidosis, which provided a novel insight for the pathogenesis at the transcriptome level.

Natural killer cell levels in adults living with type 2 diabetes: a systematic review and meta-analysis of clinical studies

Background

Chronic immune activation and hyperglycaemia are a hallmark of type 2 diabetes mellitus (T2D) while natural killer (NK) cells are involved in the pathogenesis of T2D. Dysregulated NK cell responses are associated with an increased risk of cardiovascular disease in patients living with T2D.

Objective

To provide a comprehensive and systematic evidence-based estimate on the levels of NK cells in patients living with T2D.

Results

This systematic review and meta-analysis included 13 studies reporting on 491 adult patients with T2D and 1064 nondiabetic controls. The pooled effect estimates showed increased levels of NK cells in adult patients with T2D compared to controls (MD: 0.03 [− 3.20, 3.26], I² = 97%, p < 0.00001).

Conclusion

Overall, the evidence presented in this systematic review shows that the changes in NK cells in patients living with T2D are still unclear and further studies are needed.

Enteroviral Pathogenesis of Type 1 Diabetes: The Role of Natural Killer Cells

Enteroviruses, especially group B coxsackieviruses (CV-B), have been associated with the development of chronic diseases such as type 1 diabetes (T1D). The pathological mechanisms that trigger virus-induced autoimmunity against islet antigens in T1D are not fully elucidated. Animal and human studies suggest that NK cells response to CV-B infection play a crucial role in the enteroviral pathogenesis of T1D. Indeed, CV-B-infected cells can escape from cytotoxic T cells recognition and destruction by inhibition of cell surface expression of HLA class I antigen through non-structural viral proteins, but they can nevertheless be killed by NK cells. Cytolytic activity of NK cells towards pancreatic beta cells persistently-infected with CV-B has been reported and defective viral clearance by NK cells of patients with T1D has been suggested as a mechanism leading to persistence of CV-B and triggering autoimmunity reported in these patients. The knowledge about host antiviral defense against CV-B infection is not only crucial to understand the susceptibility to virus-induced T1D but could also contribute to the design of new preventive or therapeutic approaches for individuals at risk for T1D or newly diagnosed patients.

Synchronization of the Normal Human Peripheral Immune System: A Comprehensive Circadian Systems Immunology Analysis

In this study, we sought to fill an important gap in fundamental immunology research by conducting a comprehensive systems immunology analysis of daily variation in the normal human peripheral immune system. Although variation due to circadian rhythmicity was not a significant source of variation in daily B-cell levels or any CD4+ functional subset, it accounted for more than 25% of CD4+ regulatory T-cell variation and over 50% of CD8+ central memory variation. Circadian rhythmicity demonstrated phase alignment within functional phenotypes. In addition, we observed that previously-described mechanistic relationships can also appear in the peripheral system as phase shifting in rhythmic patterns. We identified a set of immune factors which are ubiquitously correlated with other factors and further analysis also identified a tightly-correlated “core” set whose relational structure persisted after analytically removing circadian-related variation. This core set consisted of CD8+ and its subpopulations and the NK population. In sum, the peripheral immune system can be conceptualized as a dynamic, interconnected wave-field repeating its pattern on a daily basis. Our data provide a comprehensive inventory of synchronization and correlation within this wave-field and we encourage use of our data to discover unknown mechanistic relationships which can then be tested in the laboratory.

Past, present and future of latent autoimmune diabetes in adults

Latent autoimmune diabetes in adults (LADA) is the most common form of autoimmune diabetes diagnosed in adults. Similar to type 1 diabetes, the prevalence of LADA is impacted by ethnicity and geography. LADA is characterized by β cell loss due to autoimmunity and insulin resistance and has highly heterogeneous clinical features, autoimmunity, and genetics in a glutamic acid decarboxylase antibody (GADA) titre-dependent manner, suggesting LADA is part of a continuum spectrum between type 1 and type 2 diabetes. Although LADA is the most frequent form of autoimmune diabetes diagnosed in adults, clinical trials involving LADA are scarce. Here we review the recent advancements in LADA epidemiology, clinical features, pathogenesis, and interventions. We also highlight the environmental factors that are thought to play an important role in addition to genetics in the pathogenesis of LADA. In the future, high-throughput molecular profiles might shed light on the nature of LADA among the wide spectrum of diabetes and offer new opportunities to identify novel LADA-specific biomarkers.

Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Recurrent pregnancy loss (RPL) is a common complication in obstetrics, affecting about 5% of women of childbearing age. An increase in the number of abortions results in escalation in the risk of miscarriage. Although concentrated research has identified numerous causes for RPL, about 50% of them remain unexplained. Pregnancy is a complex process, comprising fertilization, implantation, organ and tissue differentiation, and fetal growth, which is effectively controlled by a number of both maternal and fetal factors. An example is the immune response, in which T cells and natural killer cells participate, and inflammation mediated by tumor necrosis factor or colony-stimulating factor, which hinders embryo implantation. Furthermore, vitamin D affects glucose metabolism and inhibits embryonic development, whereas microRNA has a negative effect on the gene expression of embryo implantation and development. This review examines the causes of RPL from multiple perspectives, and focuses on the numerous factors that may result in RPL.

Downregulation of T-Cell Transcription Factors in Adult Latent Autoimmune Diabetes with High-Titer Glutamic Acid Decaroxylase Antibody

INTRODUCTION

Latent autoimmune diabetes in adults (LADA) shows a heterogeneous clinical profile that is dependent on the glutamic acid decaroxylase antibody (GADA) titer. We speculated that LADA patients with a high or low GADA titer may have distinct T-lymphocyte subset profiles and distinct expression patterns of transcription factors involved in T-cell immunomodulation.

METHODS

Patients with LADA (n = 40) and type 2 diabetes (T2DM; n = 14) were recruited to the study, and peripheral blood mononuclear cells were isolated. The proportions of T-lymphocyte subsets (Th1 [T helper type 1], Th2 [T helper type 2], Treg [regulatory T], and Th17 [T helper type 17] cells) were determined by flow cytometry. Real-time polymerase chain reaction (PCR) was performed to estimate mRNA expression levels of the T-cell subtype-enriched transcription factors T-bet (Th1), GATA3 (Th2), transcription factor forkhead box protein 3 (FOXP3) (Treg), and RORC (Th17).

RESULTS

The frequency of Th1 (as a percentage of total CD4⁺T cells) was greater in the LADA patients with high-titer GADA than in the LADA patients with low-titer GADA (11.06 ± 1.62 vs. 7.05 ± 0.86, P = 0.030). Compared to the T2DM group, in the low-titer GADA group the frequency of Th1 was significantly reduced (7.05 ± 0.86 vs. 16.75 ± 3.73, P = 0.017) and the frequency of Th17 frequency was signficantly increased (1.11 ± 0.09 vs. 0.74 ± 0.16, P = 0.017). Compared to T2DM patients, in the high-titer GADA group there was a significantly reduced expression of FOXP3 (0.35 ± 0.13 vs. 1.75 ± 0.54, P = 0.002), RORC (0.53 ± 0.19 vs. 2.00 ± 0.77, P = 0.046), and GATA3 (0.74 ± 0.17 vs. 2.31 ± 0.91, P = 0.046). Similarly, the high-titer GADA group expressed reduced levels of FOXP3 and RORC compared to the low-titer GADA group (0.35 ± 0.13 vs. 1.50 ± 0.41, P = 0.027; 0.53 ± 0.19 vs. 1.35 ± 0.21, P  = 0.027, respectively). There was a negative correlation between FOXP3 expression level and GADA titer for the entire cohort (r = - 0.0433, P = 0.015) and a stronger negative correlation in LADA patients (r = - 0.606, P = 0.008).

CONCLUSION

LADA patients with high-titer GADA express lower levels of T-cell transcription factors, including the Treg transcription factor FOXP3, which may contribute to differences in the clinical profile compared to LADA patients with low-titer GADA.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01159847.

Cellular immunological changes in patients with LADA are a mixture of those seen in patients with type 1 and type 2 diabetes

There is currently scarce knowledge of the immunological profile of patients with latent autoimmune diabetes mellitus in the adult (LADA) when compared with healthy controls (HC) and patients with classical type 1 diabetes (T1D) and type 2 diabetes (T2D). The objective of this study was to investigate the cellular immunological profile of LADA patients and compare to HC and patients with T1D and T2D. All patients and age‐matched HC were recruited from Uppsala County. Peripheral blood mononuclear cells were isolated from freshly collected blood to determine the proportions of immune cells by flow cytometry. Plasma concentrations of the cytokine interleukin (IL)‐35 were measured by enzyme‐linked immunosorbent assay (ELISA). The proportion of CD11c⁺CD123^– antigen‐presenting cells (APCs) was lower, while the proportions of CD11c⁺CD123⁺ APCs and IL‐35⁺ tolerogenic APCs were higher in LADA patients than in T1D patients. The proportion of CD3^–CD56^highCD16⁺ natural killer (NK) cells was higher in LADA patients than in both HC and T2D patients. The frequency of IL‐35⁺ regulatory T cells and plasma IL‐35 concentrations in LADA patients were similar to those in T1D and T2D patients, but lower than in HC. The proportion of regulatory B cells in LADA patients was higher than in healthy controls, T1D and T2D patients, and the frequency of IL‐35⁺ regulatory B cells was higher than in T1D patients. LADA presents a mixed cellular immunological pattern with features overlapping with both T1D and T2D.

Pancreatic autoimmunity: An unknown etiology on patients with assisted reproductive techniques (ART)-recurrent reproductive failure

Pancreatic Autoimmunity is defined as the presence of autoantibodies and more frequent need for insulin treatment. Affected women presenting recurrent implantation failure (RIF) or recurrent miscarriage (RM) are often misdiagnosed. The objective of thestudy was to describe clinical and metabolic profiles suggestive of Pancreatic Autoimmunity and therapeutic strategy in patients with RIF/RM. We analyzed retrospectively 735 patients, and have identified a subset (N = 20) with similar metabolic characteristics. At the same time, we included a control group (n = 39), with similar demographic characteristics and negative for pancreatic, thyroid or celiac disease autoimmunity. The patients identified with autoimmune metabolic problem (N = 20) had relatives with diabetes mellitus. At 120 minutes after Oral Glucose Tolerance Test (OGTT) low level of insulin secretion (<2 IU/ml) was found in 70% of patients. Glutamic acid decarboxylase 65 (GAD 65) antibodies, with or without other autoantibodies, were positive in80% of patients and anti-IA2 alone were positive I the rest. Since pregestational period, insulin administration was recommended for 10 patients, metformin for 4 patients and exclusively diet control in 5 of them. Significantly increased live bith rates (LBR) per cycle were observed after metabolic control (52%) compared with live birth rate (LBR) after cycles without control (7.5%) (p<0.0001). We noticed 2 cases of pre-eclampsia and 6 low-birth weights. Insulin administration was needed during the pregnancy in 68% of patients and after childbirth in 31.57% of them. In our control group, all of patients (n = 39) underwent ART (53.8% SET and 46.1% DET) with a 50% (SET) and 61.9% (DET) live birth rate (LBR) per cycle. Patients with RIF/RM, normal BMI, low insulin levels after OGTT could benefit from additional metabolic immune testing. A correct diagnosis and treatment could have a positive impact on their reproductive results and live birth rate.

RAB11FIP5 Expression and Altered Natural Killer Cell Function Are Associated with Induction of HIV Broadly Neutralizing Antibody Responses

HIV-1 broadly neutralizing antibodies (bnAbs) are difficult to induce with vaccines but are generated in ∼50% of HIV-1-infected individuals. Understanding the molecular mechanisms of host control of bnAb induction is critical to vaccine design. Here, we performed a transcriptome analysis of blood mononuclear cells from 47 HIV-1-infected individuals who made bnAbs and 46 HIV-1-infected individuals who did not and identified in bnAb individuals upregulation of RAB11FIP5, encoding a Rab effector protein associated with recycling endosomes. Natural killer (NK) cells had the highest differential expression of RAB11FIP5, which was associated with greater dysregulation of NK cell subsets in bnAb subjects. NK cells from bnAb individuals had a more adaptive/dysfunctional phenotype and exhibited impaired degranulation and cytokine production that correlated with RAB11FIP5 transcript levels. Moreover, RAB11FIP5 overexpression modulated the function of NK cells. These data suggest that NK cells and Rab11 recycling endosomal transport are involved in regulation of HIV-1 bnAb development.

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Elevated RAB11FIP5 expression is associated with HIV-1 bnAb induction

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NK cells show the highest differential RAB11FIP5 expression

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NK cell subsets are more dysregulated in individuals developing bnAbs

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Rab11Fip5 regulates NK cell function

Dipeptidyl peptidase-4(DPP-4) inhibitors: promising new agents for autoimmune diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors constitute a novel class of anti-diabetic agents confirmed to improve glycemic control and preserve β-cell function in type 2 diabetes. Three major large-scale studies, EXAMINE, SAVOR-TIMI 53, and TECOS, have confirmed the cardiovascular safety profile of DPP-4 inhibitors. Based on these results, DPP-4 inhibitors have gained widespread use in type 2 diabetes treatment. It is currently unknown, however, whether DPP-4 inhibitors have similar therapeutic efficacy against autoimmune diabetes. Several in vitro and in vivo studies have addressed this issue, but the results remain controversial. In this review, we summarize experimental findings and preliminary clinical trial results, and identify potentially effective immune modulation targets of DPP-4 inhibitors for autoimmune diabetes.

Type 1 Diabetes and Its Multi-Factorial Pathogenesis: The Putative Role of NK Cells

Type 1 diabetes (T1D) affects millions of people worldwide and is the prevalent form of all pediatric diabetes diagnoses. T1D is recognized to have an autoimmune etiology, since failure in specific self-tolerance mechanisms triggers immune reactions towards self-antigens and causes disease onset. Among all the different immunocytes involved in T1D etiopathogenesis, a relevant role of natural killer cells (NKs) is currently emerging. NKs represent the interface between innate and adaptive immunity; they intervene in the defense against infections and present, at the same time, typical features of the adaptive immune cells, such as expansion and generation of memory cells. Several recent studies, performed both in animal models and in human diabetic patients, revealed aberrations in NK cell frequency and functionality in the peripheral blood and in damaged tissues, suggesting their possible redirection towards affected tissues. NKs oscillate from a quiescent to an activated state through a delicate balance of activating and inhibitory signals transduced via surface receptors. Further accurate investigations are needed to elucidate the exact role of NKs in T1D, in order to develop novel immune-based therapies able to reduce the disease risk or delay its onset.

Altered regulatory T cell phenotype in latent autoimmune diabetes of the adults (LADA)

Latent autoimmune diabetes of the adults (LADA) accounts for up to 12% of all patients with diabetes. Initially the disease resembles type 2 diabetes (T2D); however, the typical presence of β cell autoantibodies indicates an autoimmune basis of LADA. While dysfunctional regulatory T cells (Tregs ) have been implicated in autoimmune diabetes, these cells have been scarcely studied in LADA. The aim of this study was to investigate the frequency and phenotype of circulating Tregs in LADA patients early during disease progression. Flow cytometric analysis was performed on whole blood and peripheral mononuclear cells (PBMC) from patients diagnosed with LADA prior to insulin deficiency (n = 39) and from healthy volunteers (n = 20). Overall, we found the frequency and activation status of peripheral putative Tregs to be altered in LADA patients compared to healthy controls. While total T cells and CD4(+) T cells expressing high levels of CD25 (CD4(+) CD25(hi) ) were unchanged, the frequency and total numbers of CD4(+) T cells expressing an intermediate level of CD25 (CD4(+) CD25(int) ) were decreased in LADA patients. Interestingly, the expression of the Treg -specific marker forkhead box protein 3 (FoxP3), as well as the activation and memory makers CD69, cytotoxic T lymphocyte associated antigen 4 (CTLA-4), CCR4 and CD45RO were increased in CD4(+) CD25(+) T cells of the patients. Our data depict phenotypical changes in T cells of LADA patients that may reflect a derangement in peripheral immune regulation contributing to the slow process leading to insulin-dependent diabetes in these patients.

Interactions between maternal killer cell immunoglobulin receptor genes and foetal HLA ligand genes contribute to type 1 diabetes susceptibility in Han Chinese

In this study, we aimed to test the hypothesis that KIR haplotypes (that interact with HLA class I molecules) are associated with susceptibility in patients with T1DM in utero through maternal-foetal interaction of KIR and their HLA class I ligands in Han Chinese population. We determined the KIR genes and KIR/ligand gene combination frequencies in 59 Han Chinese children with T1D and their mothers and compared it with 159 healthy control children and their mothers. The absence of KIR-2DS1 in the mother and the presence of HLA-C2 ligand in the child were negatively associated with type 1 diabetes in the child. Our results indicate that maternal KIR genes and their interaction with foetal HLA-C2 may contribute to the risk of type 1 diabetes among Han Chinese children.

Altered Peripheral B-Lymphocyte Subsets in Type 1 Diabetes and Latent Autoimmune Diabetes in Adults

OBJECTIVE

B lymphocytes play an important role in the immunopathogenesis of autoimmune diabetes. We hypothesized that the altered B-cell subset phenotype is associated with autoimmune diabetes.

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes (T1D) (n = 81), latent autoimmune diabetes in adults (LADA) (n = 82), or type 2 diabetes (T2D) (n = 95) and healthy control subjects (n = 218) with normal glucose tolerance (NGT) were recruited. We determined the percentage of circulating B-lymphocyte subsets, including CD19(+)CD23(-)CD21(+) (marginal zone B [MZB]), CD19(+)CD23(+)CD21(-) (follicular B [FoB]), and CD19(+)CD5(+)CD1d(hi) (interleukin-10-producing regulatory B [B10]) cells by flow cytometry.

RESULTS

Patients with T1D or LADA had increased percentages of MZB cells and decreased percentages of FoB cells compared with healthy control subjects with NGT and patients with T2D. Moreover, patients with T1D showed the lowest frequency of B10 cells compared with patients with LADA or T2D, whereas healthy control subjects expressed the highest frequency of B10 cells. Of note, the frequency of MZB cells was negatively associated and the frequency of FoB cells was positively associated with fasting C-peptide (FCP). The frequency of B10 cells was positively correlated with FCP and negatively correlated with hemoglobin A(1c).

CONCLUSIONS

The data show that patients with T1D or LADA express an altered frequency of B-cell subsets, which is associated with islet function and glycemia. These findings suggest that B lymphocytes may be involved in loss of self-tolerance and β-cell destruction and could be used as a biomarker and potential target for immunological intervention.

Latent autoimmune diabetes of the adult: current knowledge and uncertainty

Patients with adult-onset autoimmune diabetes have less Human Leucocyte Antigen (HLA)-associated genetic risk and fewer diabetes-associated autoantibodies compared with patients with childhood-onset Type 1 diabetes. Metabolic changes at diagnosis reflect a broad clinical phenotype ranging from diabetic ketoacidosis to mild non-insulin-requiring diabetes, also known as latent autoimmune diabetes of the adult (LADA). This latter phenotype is the most prevalent form of adult-onset autoimmune diabetes and probably the most prevalent form of autoimmune diabetes in general. Although LADA is associated with the same genetic and immunological features as childhood-onset Type 1 diabetes, it also shares some genetic features with Type 2 diabetes, which raises the question of genetic heterogeneity predisposing to this form of the disease. The potential value of screening patients with adult-onset diabetes for diabetes-associated autoantibodies to identify those with LADA is emphasized by their lack of clinically distinct features, their different natural history compared with Type 2 diabetes and their potential need for a dedicated management strategy. The fact that, in some studies, patients with LADA show worse glucose control than patients with Type 2 diabetes, highlights the need for further therapeutic studies. Challenges regarding classification, epidemiology, genetics, metabolism, immunology, clinical presentation and treatment of LADA were discussed at a 2014 workshop arranged by the Danish Diabetes Academy. The presentations and discussions are summarized in this review, which sets out the current ideas and controversies surrounding this form of diabetes.

High frequency of activated NKp46(+) natural killer cells in patients with new diagnosed of latent autoimmune diabetes in adults

To determine the potential association of different subsets of NK cells with the development of latent autoimmune diabetes of adults (LADA) in patients. The frequency of different subsets of NK and NKT cells, including IFN-γ(+) and CD107a(+) NK and NKT cells, in 27 patients with newly diagnosed LADA and 20 healthy controls (HC) were determined by flow cytometry. The concentrations of serum autoantibodies against GAD65 were measured by direct radioligand assay. The potential association of the frequency of NK cells with clinical measures was analyzed. In comparison with that in the HC, significantly higher frequency of peripheral blood NK and NKp46(+) NK cells, but lower frequency of KIR3DL1(+) NK cells were detected in patients with newly diagnosed LADA (p < 0.0001, p < 0.0001, p = 0.0039, respectively). The percentages of inducible IFN-γ(+) NK cells were significantly higher in the LADA patients than that in the HC (p < 0.0001). Moreover, the percentages of NKp46(+) NK cells were negatively correlated with the levels of fasting plasma C-peptide in patients (R = -0.4877, p = 0.0099). There was no significant difference in the frequency of spontaneous and inducible CD107a(+) between patients and controls. Our data indicate a higher frequency of activated NKp46(+) NK cells may be associated with the development of LADA in humans.

High GADA titer increases the risk of insulin requirement in LADA patients: a 7-year follow-up (NIRAD study 7)

OBJECTIVE

The aim of this study was to determine whether glutamic acid decarboxylase antibody (GADA) titer and other clinical parameters could define the risk of progression to insulin therapy in latent autoimmune diabetes in adults (LADA) patients during a 7-year follow-up.

METHODS

This study involved 220 LADA and 430 type 2 diabetes subjects followed up for 7 years from the time of GADA screening to evaluate their progression toward insulin therapy. Kaplan-Meier curves and multivariate logistic regression analysis were performed to identify the markers capable of influencing this progression.

RESULTS

During the follow-up, the drop out was 4% in both groups. A total of 119 (56.1%) out of 212 LADA patients required insulin during the 7 years of follow-up. The Kaplan-Meier plots showed that 74/104 (71.1%) of high GADA titer required insulin compared with 45/108 (41.6%) of low GADA titer and with 86/412 (20.9%) of type 2 diabetes (P<0.0001 for both). A BMI of ≤25 kg/m2 and IA-2IC and zinc transporter 8 (ZnT8) positivity were also shown as the markers of faster progression (P<0.0001 for both). The proportion of LADA patients requiring insulin was significantly higher in the group of subjects treated also with sulfonylurea in the first year from diagnosis compared with those treated with diet and/or insulin sensitizers (P<0.001). The multivariate analysis confirmed that the presence of high GADA titer was a significant predictor of insulin requirement (P<0.0001, OR=6.95).

CONCLUSIONS

High GADA titer, BMI ≤ 25, ZnT8 and IA-2IC positivity and sulfonylurea treatment, in the first year from diagnosis, significantly increase the progression toward insulin requirement in LADA patients.

The role of p38 MAPK in the aetiopathogenesis of psoriasis and psoriatic arthritis

The pathogenetic mechanisms responsible for the induction of immune-mediated disorders, such as psoriasis, remain not well characterized. Molecular signaling pathways are not well described in psoriasis, as well as psoriatic arthritis, which is seen in up to 40% of patients with psoriasis. Signaling pathway defects have long been hypothesized to participate in the pathology of psoriasis, yet their implication in the altered psoriatic gene expression still remains unclear. Emerging data suggest a potential pathogenic role for mitogen activated protein kinases p38 (p38 MAPK) extracellular signal-regulated kinase 1/2 (ERK1/2), and c-Jun N-terminal kinase (JNK) in the development of psoriasis. The data are still limited, though, for psoriatic arthritis. This review discusses the current data suggesting a crucial role for p38 MAPK in the pathogenesis of these disorders.

Natural killer cell function, an important target for infection and tumor protection, is impaired in type 2 diabetes

Patients with Type 2 diabetes (T2D) are highly susceptible to infection and have an increased incidence of some tumors, possibly due to immune system dysfunction. In the innate cellular immune system, Natural Killer (NK) lymphocytes are important effectors responsible for controlling infections and combating tumor development. We analyzed NK cell subsets in 51 patients with long-standing T2D. Compared with healthy blood donors, diabetic patients showed a profound decrease in both NKG2D-positive NK cells (44% vs. 55.5%, P<0.01) and NKp46-positive cells (26% vs. 50%, P<0.01). Decreased expression of these receptors was associated with functional defects, such as reduced NK degranulation capacity when challenged with the tumor target cell line K562 (10.3 vs. 15.8%, P<0.05). This defect could be restored in vitro by stimulating NK cells from T2D patients with IL-15 (P<0.05). NKG2D expression was found to be negatively correlated with HBA1c level (r=-0.50; P=0.009), suggesting that sustained hyperglycemia could directly influence NK cell defects. We demonstrated that endoplasmic reticulum (ER) stress, an important mediator in diabetes-associated complications, was inducible in vitro in normal NK cells and that tunicamycin treatment resulted in a significant decrease in NKG2D expression (P<0.05). Furthermore, markers of the Unfolded Protein Response (UPR) BiP, PDI and sXBP1 mRNAs were significantly increased in NK cells from T2D patients (P<0.05, P<0.01, P<0.05, respectively), indicating that ER stress is activated in vivo through both PERK and IRE1 sensors. These results demonstrate for the first time defects in NK cell-activating receptors NKG2D and NKp46 in T2D patients, and implicate the UPR pathway as a potential mechanism. These defects may contribute to susceptibility to infections and malignancies and could be targetted therapeutically.

High frequency of activated natural killer and natural killer T-cells in patients with new onset of type 2 diabetes mellitus

Chronic low-grade inflammation is crucial for the development of insulin resistance and type 2 diabetes mellitus (T2DM), and immunocompetent cells, such as T-cells, B-cells, mast cells and macrophages, regulate the pathogenesis of T2DM. However, little is known about the role of natural killer (NK) and natural killer T (NKT) cells in the pathogenic process of T2DM. A total of 16 patients with new onset T2DM and nine healthy subjects were recruited, and the frequency of peripheral blood activated and inhibitory NK and NKT cells in individual subjects was determined by flow cytometry. The frequency of spontaneous and inducible interferon gamma (IFN- γ) and CD107a+ NK cells was further examined, and the potential association of the frequency of NK cells with clinical measures was analyzed. While there was no significant difference in the frequency of peripheral blood NK and NKT cells between patients and controls, the frequency of NKG2D+ NK and NKT cells in patients was significantly higher than those in the controls ( P = 0.011). In contrast, the frequency of NKG2A+ and KIR2DL3+ inhibitory NK and NKT cells in patients was significantly lower than those in the controls ( P = 0.002, P < 0.0001, respectively). Furthermore, the frequencies of NKG2D+ NK cells were correlated significantly with the values of body mass index in patients. Moreover, the frequencies of spontaneous and inducible CD107a+, but not IFN- γ-secreting, NK cells in patients were significantly higher than those in the controls ( P < 0.004, P < 0.0001). Our data indicated that a higher frequency of activated NK cells may participate in the obesity-related chronic inflammation involved in the pathogenesis of T2DM.