Immunophenotyping of rheumatoid arthritis reveals a linkage between HLA-DRB1 genotype, CXCR4 expression on memory CD4(+) T cells, and disease activity

The effect of type 1 diabetes protection and susceptibility associated HLA class II genotypes on DNA methylation in immune cells

The HLA region, especially HLA class I and II genes, which encode molecules for antigen presentation to T cells, plays a major role in the predisposition to autoimmune disorders. To clarify the mechanisms behind this association, we examined genome-wide DNA methylation by microarrays to cover over 850,000 CpG sites in the CD4+ T cells and CD19+ B cells of healthy subjects homozygous either for DRB1*15-DQA1*01-DQB1*06:02 (DR2-DQ6, n = 14), associated with a strongly decreased T1D risk, DRB1*03-DQA1*05-DQB1*02 (DR3-DQ2, n = 19), or DRB1*04:01-DQA1*03-DQB1*03:02 (DR4-DQ8, n = 17), associated with a moderately increased T1D risk. In total, we discovered 14 differentially methylated CpG probes, of which 10 were located in the HLA region and six in the HLA-DRB1 locus. The main differences were between the protective genotype DR2-DQ6 and the risk genotypes DR3-DQ2 and DR4-DQ8, where the DR2-DQ6 group was hypomethylated compared to the other groups in all but four of the differentially methylated probes. The differences between the risk genotypes DR3-DQ2 and DR4-DQ8 were small. Our results indicate that HLA variants have few systemic effects on methylation and that their effect on autoimmunity is conveyed directly by HLA molecules, possibly by differences in expression levels or function.

Individual and population-level variability in HLA-DR associated immunogenicity risk of biologics used for the treatment of rheumatoid arthritis

Hypothesis

While conventional in silico immunogenicity risk assessments focus on measuring immunogenicity based on the potential of therapeutic proteins to be processed and presented by a global population-wide set of human leukocyte antigen (HLA) alleles to T cells, future refinements might adjust for HLA allele frequencies in different geographic regions or populations, as well for as individuals in those populations. Adjustment by HLA allele distribution may reveal risk patterns that are specific to population groups or individuals, which current methods that rely on global-population HLA prevalence may obscure.

Key findings

This analysis uses HLA frequency-weighted binding predictions to define immunogenicity risk for global and sub-global populations. A comparison of assessments tuned for North American/European versus Japanese/Asian populations suggests that the potential for anti-therapeutic responses (anti-therapeutic antibodies or ATA) for several commonly prescribed Rheumatoid Arthritis (RA) therapeutic biologics may differ, significantly, between the Caucasian and Japanese populations. This appears to align with reports of differing product-related immunogenicity that is observed in different populations.

Relevance to clinical practice

Further definition of population-level (regional) and individual patient-specific immunogenic risk profiles may enable prescription of the RA therapeutic with the highest probability of success to each patient, depending on their population of origin and/or their individual HLA background. Furthermore, HLA-specific immunogenicity outcomes data are limited, thus there is a need to expand HLA-association studies that examine the relationship between HLA haplotype and ATA in the clinic.

Comparative single-cell multiplex immunophenotyping of therapy-naive patients with rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus shed light on disease-specific composition of the peripheral immune system

Introduction

Systemic autoimmune diseases (SADs) are a significant burden on the healthcare system. Understanding the complexity of the peripheral immunophenotype in SADs may facilitate the differential diagnosis and identification of potential therapeutic targets.

Methods

Single-cell mass cytometric immunophenotyping was performed on peripheral blood mononuclear cells (PBMCs) from healthy controls (HCs) and therapy-naive patients with rheumatoid arthritis (RA), progressive systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). Immunophenotyping was performed on 15,387,165 CD45+ live single cells from 52 participants (13 cases/group), using an antibody panel to detect 34 markers.

Results

Using the t-SNE (t-distributed stochastic neighbor embedding) algorithm, the following 17 main immune cell types were determined: CD4+/CD57- T cells, CD4+/CD57+ T cells, CD8+/CD161- T cells, CD8+/CD161+/CD28+ T cells, CD8dim T cells, CD3+/CD4-/CD8- T cells, TCRγ/δ T cells, CD4+ NKT cells, CD8+ NKT cells, classic NK cells, CD56dim/CD98dim cells, B cells, plasmablasts, monocytes, CD11cdim/CD172dim cells, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs). Seven of the 17 main cell types exhibited statistically significant frequencies in the investigated groups. The expression levels of the 34 markers in the main populations were compared between HCs and SADs. In summary, 59 scatter plots showed significant differences in the expression intensities between at least two groups. Next, each immune cell population was divided into subpopulations (metaclusters) using the FlowSOM (self-organizing map) algorithm. Finally, 121 metaclusters (MCs) of the 10 main immune cell populations were found to have significant differences to classify diseases. The single-cell T-cell heterogeneity represented 64MCs based on the expression of 34 markers, and the frequency of 23 MCs differed significantly between at least twoconditions. The CD3- non-T-cell compartment contained 57 MCs with 17 MCs differentiating at least two investigated groups. In summary, we are the first to demonstrate the complexity of the immunophenotype of 34 markers over 15 million single cells in HCs vs. therapy-naive patients with RA, SSc, and SLE. Disease specific population frequencies or expression patterns of peripheral immune cells provide a single-cell data resource to the scientific community.

Significance of m6A in subtype identification, immunological evolution, and therapeutic sensitivity of RA

N6-methyladenosine (m6A) is one kind of important epigenetic modification pattern which is extensively involved in immune regulation. The development and progression of autoimmune diseases are closely related to immune dysregulation. Considering that rheumatoid arthritis (RA) is a typical autoimmune disease, the m6A process might be one of the important regulatory mechanisms in the pathogenesis of RA. In this study, we identified five differentially expressed m6A regulators in normal and RA samples from the GEO database. With these five regulators, we constructed the nomogram, and it could accurately identify the risk of RA morbidity. Next, we identified 121 differentially expressed genes (DEGs) between normal and RA samples, of which 36 DEGs were co-expressed with these five m6A regulators. We noted that these DEGs were highly enriched in multiple immunoregulatory signaling pathways, such as cytokine-mediated immune cell chemotaxis, adhesion, and activation. To further characterize the heterogeneity of immunological features, we clustered the RA samples into two subtypes. The C2 subtype has higher infiltration levels of pro-inflammatory cells and activity of pro-inflammatory signaling pathways. Thus, the inflammatory response might be more vigorous in the C2 subtype. Next, we constructed the m6Asig system with the SVM machine learning algorithms and least absolute shrinkage and selection operator (LASSO) regression. The m6Asig could accurately distinguish the C1 and C2 subtypes, which indicated that the m6Asig could be a potential biomarker for the inflammatory activity of RA. Finally, by comparing the information from the CellMiner, TTD, and DrugBank databases, we determined 25 drugs. The targets of these drugs were positively correlated with m6Asig. To be clarified, the above findings were derived from bioinformatics and statistical analyses, and further experimental validation still requires. In summary, this study further revealed the m6A and immunoregulation mechanisms in RA pathogenesis. Also, the m6Asig could be a novel biomarker with potential applicability in the clinical management of RA.

MOG-specific T cell response amplified in para- and post-SAR-CoV-2 infection in myelin oligodendrocyte glycoprotein antibody-associated disease

We describe clinical characteristics and deep immunophenotypes in two patients with myelin-oligodendrocyte-glycoprotein (MOG)-antibody-associated-disease after COVID-19. The para-COVID case was a 74-year-old man who developed optic neuritis two days after COVID-19. Immunological assays revealed reduced absolute CD8+ T- and B-cell counts with increased frequency of NK cells. Post-COVID case was a 63-year-old man with optic neuritis six months after COVID-19, a frequency of CD8+ T-cells was elevated with a relatively low fraction of naïve and a high fraction of effector memory CD8+ T-cells. There was increased frequency of CD8+CD38+HLA-DR+ T-cells in the para-COVID case; interestingly, CD4+CD38+HLA-DR+ T cell frequency was increased in the post-COVID case. Both had increased SARS-CoV-2-specific and MOG-specific T-cell responses.

Research Progress of CXCR4-Targeting Radioligands for Oncologic Imaging

C-X-C motif chemokine receptor 4 (CXCR4) plays a key role in various physiological functions, such as immune processes and disease development, and can influence angiogenesis, proliferation, and distant metastasis in tumors. Recently, several radioligands, including peptides, small molecules, and nanoclusters, have been developed to target CXCR4 for diagnostic purposes, thereby providing new diagnostic strategies based on CXCR4. Herein, we focus on the recent research progress of CXCR4-targeting radioligands for tumor diagnosis. We discuss their application in the diagnosis of hematological tumors, such as lymphomas, multiple myelomas, chronic lymphocytic leukemias, and myeloproliferative tumors, as well as nonhematological tumors, including tumors of the esophagus, breast, and central nervous system. Additionally, we explored the theranostic applications of CXCR4-targeting radioligands in tumors. Targeting CXCR4 using nuclear medicine shows promise as a method for tumor diagnosis, and further research is warranted to enhance its clinical applicability.

The Association of Human Leukocyte Antigen Genotyping Among Sudanese Patients With Rheumatoid Arthritis: Reference to Ethnicity

INTRODUCTION

 Human leukocyte antigens (HLA) account for up to one-half of the total genetic contribution to rheumatoid arthritis (RA) risk. The study investigated the association of HLA class II genotyping with RA susceptibility in Sudanese ethnic groups.

METHODS

 The DRB1 and DQB1 alleles and haplotypes were determined in 122 RA patients (i.e., Gaalia = 54, Johayna = 24, Baggara = 17, Nile Nubian = 12, and others = 15) and 120 healthy controls of ethnic groups (i.e., Gaalia = 44, Johayna = 11, Baggara = 15, Nile Nubian = 9, and others = 21) using a polymerase chain reaction with sequence-specific primers method.

RESULTS

Susceptibility to RA was associated with a high frequency of DRB1*04 (P = 0.04), DRB1*10 (P = 0.04), and DQB1*03 (P = 2.2 x 10-8/Pc = 6.6 x 10-8) between study ethnic groups, while protective effects were shown with DRB1*07 (P = 0.01), DQB1*02 (P = 0.02), and DQB1*06 (P = 2.2 x 10-6/Pc = 6.6 x 10-6), with an inconsistent frequency between study ethnic groups. The HLA haplotypes that were high in frequency among RA ethnic groups and showed susceptibility associations were DRB1*03-DQB1*03, DRB1*04-DQB1*03, DRB1*08-DQB1*03, DRB1*13-DQB1*02, and DRB1*13-DQB1*03 (P = 0.00003/Pc = 0.0003, P = 0.0001/Pc = 0.0001, P = 0.03, P = 0.004/Pc = 0.03, and P = 3.79x10-8/Pc = 3.3x10-9, respectively). On the contrary, DRB1*03-DQB1*02, DRB1*07-DQB1*02, and DRB1*13-DQB1*06 were lower in frequency in the ethnic groups with RA and may confer protection (P = 0.004/Pc = 0.032, P = 0.002/Pc = 0.02, and P = 0.01, respectively).

CONCLUSIONS

Our findings indicate an association between HLA-DRB1 and DQB1 genotypes and the susceptibility to RA in the Sudanese population, with a moderate frequency between our ethnic groups.

Dynamics of circulating follicular helper T cell subsets and follicular regulatory T cells in rheumatoid arthritis patients according to HLA-DRB1 locus

B cells, follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are part of a circuit that may play a role in the development or progression of rheumatoid arthritis (RA). With the aim of providing further insight into this topic, here we evaluated the frequency of different subsets of Tfh and Tfr in untreated and long-term treated RA patients from a cohort of Argentina, and their potential association with particular human leukocyte antigen (HLA) class-II variants and disease activity. We observed that the frequency of total Tfh cells as well as of particular Tfh subsets and Tfr cells were increased in seropositive untreated RA patients. Interestingly, when analyzing paired samples, the frequency of Tfh cells was reduced in synovial fluid compared to peripheral blood, while Tfr cells levels were similar in both biological fluids. After treatment, a decrease in the CCR7^loPD1^hi Tfh subset and an increase in the frequency of Tfr cells was observed in blood. In comparison to healthy donors, seropositive patients with moderate and high disease activity exhibited higher frequency of Tfh cells while seropositive patients with low disease activity presented higher Tfr cell frequency. Finally, we observed that HLA-DRB1*09 presence correlated with higher frequency of Tfh and Tfr cells, while HLA-DRB1*04 was associated with increased Tfr cell frequency. Together, our results increase our knowledge about the dynamics of Tfh and Tfr cell subsets in RA, showing that this is altered after treatment.

Synovial gene signatures associated with the development of rheumatoid arthritis in at risk individuals: A prospective study

OBJECTIVE

To identify molecular changes in synovium before arthritis development in individuals at risk of developing rheumatoid arthritis (RA).

MATERIALS AND METHODS

We included 67 IgM rheumatoid factor and/or anti-citrullinated protein antibody positive individuals with arthralgia but without arthritis. Synovial biopsies were collected after which individuals were prospectively followed for at least 2 years during which 17 developed arthritis. An exploratory genome-wide transcriptional profiling study was performed in 13 preselected individuals to identify transcripts associated with arthritis development (n = 6). Findings were validated using quantitative real-time PCR and immunohistochemistry in the total cohort.

RESULTS

Microarray-based survival analyses identified 5588 transcripts whose expression levels in synovium were significantly associated with arthritis development. Pathway analysis revealed that synovial tissue of at risk individuals who later developed arthritis display higher expression of genes involved in adaptive immune response-related pathways compared to at risk individuals who did not develop arthritis. Lower expression was observed for genes involved in extracellular matrix receptor interaction, Wnt-mediated signal transduction and lipid metabolism. Two-way hierarchical clustering analyses of a 27-gene signature separated the total at risk cohort into two groups, where pre-RA individuals preferred to cluster together. Immunohistochemistry studies revealed more podoplanin positive cells and lower lipid droplet staining in synovial tissue from pre-RA individuals.

CONCLUSION

Synovial alterations in adaptive immune response and lipid metabolism are associated with future development of arthritis. Since this data show synovial changes without overt cellular infiltration, these may be attributed to preclinical changes in resident synovial tissue cells such as fibroblasts, macrophages and tissue resident T cells.

Migration and homeostasis of regulatory T cells in rheumatoid arthritis

Regulatory T (T_reg) cells are garnering increased attention in research related to autoimmune diseases, including rheumatoid arthritis (RA). They play an essential role in the maintenance of immune homeostasis by restricting effector T cell activity. Reduced functions and frequencies of T_reg cells contribute to the pathogenesis of RA, a common autoimmune disease which leads to systemic inflammation and erosive joint destruction. T_reg cells from patients with RA are characterized by impaired functions and by an altered phenotype. They show increased plasticity towards Th17 cells and a reduced suppressive capacity. Besides the suppressive function of T_reg cells, their effectiveness is determined by their ability to migrate into inflamed tissues. In the past years, new mechanisms involved in T_reg cell migration have been identified. One example of such a mechanism is the phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Efficient migration of T_reg cells requires the presence of VASP. IL-6, a cytokine which is abundantly present in the peripheral blood and in the synovial tissue of RA patients, induces posttranslational modifications of VASP. Recently, it has been shown in mice with collagen-induced arthritis (CIA) that this IL-6 mediated posttranslational modification leads to reduced T_reg cell trafficking. Another protein which facilitates T_reg cell migration is G-protein-signaling modulator 2 (GPSM2). It modulates G-protein coupled receptor functioning, thereby altering the cellular activity initiated by cell surface receptors in response to extracellular signals. The almost complete lack of GPSM2 in T_reg cells from RA patients contributes to their reduced ability to migrate towards inflammatory sites. In this review article, we highlight the newly identified mechanisms of T_reg cell migration and review the current knowledge about impaired T_reg cell homeostasis in RA.

Peripheral distributions of IL-4-producing CD4 + T cells and CD4 + CD25 + FoxP3 + T cells (Tregs) in rheumatoid arthritis patients with poor response to therapy are associated with HLA shared epitope alleles and ACPA status

Specific profiling of CD4 + T cell subsets in the circulation and inflamed joints of rheumatoid arthritis (RA) patients may have therapeutic implications. This study aimed to evaluate the peripheral distributions of Th2 and Treg cells in relation to HLA-shared epitope (SE) alleles and anti-cyclic citrullinated peptide antibody (ACPAs) status in patients with good response (GR) and poor response (PR) to treatment. The frequencies of IL-4-producing CD4 + T cells (Th2) and CD4 + CD25 + Foxp3 + T cells (Tregs) were determined by flow cytometry in 167 RA patients including 114 GR and 53 PR cases. CD4 + T cell subsets were also analyzed based on HLA-SE and ACPAs statuses. One hundred nine of 167 patients were positives for HLA-SE, 63.4% for ACPAs, 43.7% for SE/ACPAs and 14.9% were negatives for SE/ACPAs. Higher frequencies of Th2 (P = 0.001) and Treg cells (P = 0.03) were found in the patients versus controls. Increased and decreased frequencies of Th2 and Tregs cells were observed in the PR versus GR patients respectively (P = 0.003 and P = 0.004). Higher proportions of Th2 cells were observed in the SE⁺RA versus SE^-RA (P = 0.001), in ACPA⁺RA versus ACPA^-RA (P = 0.005) and in the SE⁺ACPA⁺RA versus SE^-ACPA^-RA patients (P = 0.002). Treg cells frequencies decreased in the SE⁺RA versus SE^-RA (P = 0.03) and in SE⁺ACPA⁺RA versus SE^-ACPA^-RA (P = 0.02). ACPA⁺GR and SE⁺PR patients showed higher proportions of Th2 cells than ACPA^-GR and SE^-PR patients respectively (P = 0.02 and P = 0.01). Analysis of the CD4 + T cell subsets profiles in conjunction with genetic background and autoantibodies patterns can be useful for precise therapeutic response monitoring in the RA patients.

Immune Dysregulation in Autism Spectrum Disorder: What Do We Know about It?

Autism spectrum disorder (ASD) is a group of complex multifactorial neurodevelopmental disorders characterized by a wide and variable set of neuropsychiatric symptoms, including deficits in social communication, narrow and restricted interests, and repetitive behavior. The immune hypothesis is considered to be a major factor contributing to autism pathogenesis, as well as a way to explain the differences of the clinical phenotypes and comorbidities influencing disease course and severity. Evidence highlights a link between immune dysfunction and behavioral traits in autism from several types of evidence found in both cerebrospinal fluid and peripheral blood and their utility to identify autistic subgroups with specific immunophenotypes; underlying behavioral symptoms are also shown. This review summarizes current insights into immune dysfunction in ASD, with particular reference to the impact of immunological factors related to the maternal influence of autism development; comorbidities influencing autism disease course and severity; and others factors with particular relevance, including obesity. Finally, we described main elements of similarities between immunopathology overlapping neurodevelopmental and neurodegenerative disorders, taking as examples autism and Parkinson Disease, respectively.

Canonical (CD74/CD44) and Non-Canonical (CXCR2, 4 and 7) MIF Receptors Are Differentially Expressed in Rheumatoid Arthritis Patients Evaluated by DAS28-ESR

Macrophage migration inhibitory factor (MIF) significantly contributes to rheumatoid arthritis (RA) pathogenesis. We aimed to evaluate the canonical (CD74/CD44) and non-canonical MIF receptors (CXCR2,4 and 7) expression and sCD74 to establish their association with RA clinical activity according to DAS28-ESR.

METHODOLOGY

101 RA patients with different clinical activities (remission (n = 27), low (n = 16), moderate (n = 35) and high (n = 23)) and 9 control subjects (CS) were included. Expression was evaluated by flow cytometry and levels of soluble CD74 (sCD74) by ELISA. Data analysis was performed with FlowJov10.0, STATAv12.0, and GraphPad Prism v7.0.

RESULTS

According to disease activity, CXCR7 expression (percentage of expression and mean fluorescence intensity (MFI)) was higher in granulocytes from patients in remission, while the expression of CXCR4 was higher in patients with high disease activity (p < 0.05). The expression of CD74 was higher in B cells (p < 0.05) and monocytes (p < 0.01) from patients in remission. Regarding sCD74 levels these were higher in patients with high disease activity when compared to those in remission (p <0.05).

CONCLUSIONS

The results support the need for further study of the role of sCD74 as a soluble MIF decoy receptor, sequestering it to negatively regulate MIF signaling though its membrane receptors. The expression patterns of CXCR4 and CXCR7 show that the latter is a scavenger-type receptor that prevents endocytosis and even degradation of CXCR4 under inflammatory conditions.

N6 -Methyladenosine and Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA), one of the most common autoimmune diseases, is characterized by immune cell infiltration, fibroblast-like synovial cell hyperproliferation, and cartilage and bone destruction. To date, numerous studies have demonstrated that immune cells are one of the key targets for the treatment of RA. N⁶-methyladenosine (m⁶A) is the most common internal modification to eukaryotic mRNA, which is involved in the splicing, stability, export, and degradation of RNA metabolism. m⁶A methylated-related genes are divided into writers, erasers, and readers, and they are critical for the regulation of cell life. They play a significant role in various biological processes, such as virus replication and cell differentiation by controlling gene expression. Furthermore, a growing number of studies have indicated that m⁶A is associated with the occurrence of numerous diseases, such as lung cancer, bladder cancer, gastric cancer, acute myeloid leukemia, and hepatocellular carcinoma. In this review, we summarize the history of m6A research and recent progress on RA research concerning m⁶A enzymes. The relationship between m⁶A enzymes, immune cells, and RA suggests that m⁶A modification offers evidence for the pathogenesis of RA, which will help in the development of new therapies for RA.

Prednisone Reprograms the Transcriptional Immune Cell Landscape in CNS Autoimmune Disease

Glucocorticoids (GCs) are widely used immunosuppressive drugs for autoimmune diseases, although considerable gaps exist between current knowledge of the mechanisms of GCs and their conclusive immune-regulatory effects. Here we generated a single-cell transcriptional immune cell atlas based on prednisone-treated or untreated experimental autoimmune uveitis (EAU) mice. Immune cells were globally activated in EAU, and prednisone partially reversed this effect in terms of cell composition, gene expression, transcription factor regulation, and cell-cell communication. Prednisone exerted considerable rescue effects on T and B cells and increased the proportion of neutrophils. Besides commonly regulated transcriptional factors (Fosb, Jun, Jund), several genes were only regulated in certain cell types (e.g. Cxcr4 and Bhlhe40 in T cells), suggesting cell-type-dependent immunosuppressive properties of GC. These findings provide new insights into the mechanisms behind the properties and cell-specific effects of GCs and can potentially benefit immunoregulatory therapy development.

Anti-HIV-1 Activity of pepRF1, a Proteolysis-Resistant CXCR4 Antagonist Derived from Dengue Virus Capsid Protein

There is an urgent need for the development of new anti-HIV drugs that can complement existing medicines to be used against resistant strains. Here, we report the anti-HIV-1 peptide pepRF1, a human serum-resistant peptide derived from the Dengue virus capsid protein. In vitro, pepRF1 shows a 50% inhibitory concentration of 1.5 nM with a potential therapeutic window higher than 53 000. This peptide is specific for CXCR4-tropic strains, preventing viral entry into target cells by binding to the viral coreceptor CXCR4, acting as an antagonist of this receptor. pepRF1 is more effective than T20, the only peptide-based HIV-1 entry inhibitor approved, and excels in inhibiting a HIV-1 strain resistant to T20. Potentially, pepRF1 can be used alone or in combination with other anti-HIV drugs. Furthermore, one can also envisage its use as a novel therapeutic strategy for other CXCR4-related diseases.

Radiolabeled Peptides and Antibodies in Medicine

Radiolabeled peptides are a relatively new, very specific radiotracer group, which is still expanding. This group is very diverse in terms of peptide size. It contains very small structures containing several amino acids and whole antibodies. Moreover, radiolabeled peptides are diverse in terms of the binding aim and therapeutic or diagnostic applications. The majority of this class of radiotracers is utilized in oncology, where the same structure can be used in therapy and diagnostic imaging by varying the radionuclide. In this study, we collected new reports of radiolabeled peptide applications in diagnosis and therapy in oncology and other fields of medicine. Radiolabeled peptides are also increasingly being used in rheumatology, cardiac imaging, or neurology. The studies collected in this review concern new therapeutic and diagnostic procedures in humans and new structures tested on animals. We also performed an analysis of clinical trials, which concerns application of radiolabeled peptides and antibodies that were reported in the clinicaltrials.gov database between 2008 and 2018.

Current Understanding of an Emerging Role of HLA-DRB1 Gene in Rheumatoid Arthritis-From Research to Clinical Practice

Rheumatoid arthritis (RA) is an autoimmune disease with an unclear pathogenic mechanism. However, it has been proven that the key underlying risk factor is a genetic predisposition. Association studies of the HLA-DRB1 gene clearly indicate its importance in RA morbidity. This review presents the current state of knowledge on the impact of HLA-DRB1 gene, functioning both as a component of the patient’s genome and as an environmental risk factor. The impact of known HLA-DRB1 risk variants on the specific structure of the polymorphic HLA-DR molecule, and epitope binding affinity, is presented. The issues of the potential influence of HLA-DRB1 on the occurrence of non-articular disease manifestations and response to treatment are also discussed. A deeper understanding of the role of the HLA-DRB1 gene is essential to explore the complex nature of RA, which is a result of multiple contributing factors, including genetic, epigenetic and environmental factors. It also creates new opportunities to develop modern and personalized forms of therapy.

Phthalate Exposure During the Prenatal and Lactational Period Increases the Susceptibility to Rheumatoid Arthritis in Mice

The prenatal and early postnatal period is highly sensitive to environmental exposures that may interfere with the developmental programming of the immune system leading to an altered disease risk in later life. To clarify the role of early influences in activation or exacerbation of autoimmune diseases like rheumatoid arthritis (RA) we investigated the effect of maternal exposure during the prenatal and lactational period of DBA/1 mice to the plasticizer benzyl butyl phthalate (BBP) on the development of RA in the offspring. Using a mild collagen-induced arthritis (CIA) model, maternal BBP-exposure increased both the prevalence and the severity of RA in the progeny compared to un-exposed dams. Additionally, maternal BBP exposure led to elevated serum IgG₁ and IgG_2a level in the offspring and increased the IFN-γ and IL-17 release from collagen-re-stimulated spleen cells. Transcriptome analysis of splenocytes isolated from 3-week-old pups before RA-induction revealed considerable changes in gene expression in the offspring from BBP-exposed dams. Among them were regulator of G-protein signaling 1 (rgs1), interleukin-7 receptor (il-7r) and CXC chemokine 4 (cxcr4), all genes that have previously been described as associated with RA pathology. In summary, our results demonstrate that perinatal exposure to BBP increases the susceptibility of the offspring to RA, probably via a phthalate-induced disturbed regulation of RA-relevant genes or signaling pathways.

Circulating IFN-γ producing CD4+ T cells and IL-17A producing CD4+ T cells, HLA-shared epitope and ACPA may characterize the clinical response to therapy in rheumatoid arthritis patients

This study analyzed the association between peripheral distributions of helper T cell subsets, HLA shared-epitope (SE), anti-cyclic citrullinated peptide antibody (ACPA) and clinical response to therapy in rheumatoid arthritis (RA) patients. Frequencies of IFN-γ-producing CD4+T (Th1) and IL-17A-producing CD4+T (Th17) cells were determined by flow cytometry in 167 patients (114 cases with good-response (GR) and 53 poor-response (PR) based on DAS28). HLA-DRB1 alleles for patients and 150 healthy controls were determined by PCR-SSP. We observed that 65.2% of RA patients were SE⁺, 63.4%ACPA⁺, 43.7%SE⁺ACPA⁺ and 14.9% were SE^-ACPA^-. Higher significantly proportions of Th1 and Th17 cells were found in RA patients than controls (P < 0.05) as well as in the SE⁺ or ACPA⁺RA patients compared to SE^- and ACPA^- patients. Increased frequencies of both Th subsets were found in SE⁺ACPA⁺ versus SE^-ACPA^- patients (P < 0.001) and in the PR versus GR group (P < 0.001). We showed significant differences for Th cells frequencies between SE⁺ and SE^- patients in both groups, and between ACPA⁺ and ACPA^- cases in the PR group. Our findings suggest a close link between Th1 and Th17 cells proportions and HLA-SE/ACPA in the RA patients and remarkably in the PR group which could be indicative for the importance of immune monitoring for evaluation of response to therapy.

Decreased peripheral blood memory B cells are associated with the presence of interstitial lung disease in rheumatoid arthritis: a case-control study

OBJECTIVES

Interstitial lung disease sometimes occurs in rheumatoid arthritis patients. Although the underlying immunological mechanisms responsible for interstitial lung disease associated with rheumatoid arthritis have not yet been clarified, some reports have suggested possible roles of B cells. To examine the role of B-cell subsets in interstitial lung disease in rheumatoid arthritis patients, we analyzed peripheral blood B-cell subsets.

METHODS

We analyzed the frequencies of the peripheral blood B-cell subsets by flow cytometry in rheumatoid arthritis patients with and without interstitial lung disease (n = 16 and 81, respectively) and in healthy donors (n = 110) by high-resolution computed tomography.

RESULTS

Compared with healthy donors, rheumatoid arthritis patients showed statistically higher frequencies of naive B cells and lower frequencies of memory B cells. Moreover, the frequencies of memory B cells were lower in rheumatoid arthritis patients with interstitial lung disease than in those without. Multivariate analysis showed that the frequency of memory B cells, particularly switched memory B cells, was significantly decreased in rheumatoid arthritis patients with interstitial lung disease, even after adjusting for prednisolone dose.

CONCLUSIONS

We suspect memory B cells play important roles in interstitial lung disease associated with rheumatoid arthritis.

Genetic and epigenetic alteration of the programmed cell death 1 in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease where both genetics and epigenetics are contributing factors. In order to discover genetic and epigenetic associations with RA and its phenotypes, we analysed RNA expression, DNA variations and DNA methylation of programmed cell death 1 (PDCD1) in a cohort of RA patients and healthy controls.

METHODS

RA patients (n = 206) and healthy controls (n = 234) were included for analysis of PDCD1 expression, PDCD1 polymorphisms and PDCD1 methylation. Differences in continuous variables between groups were compared by applying t tests. Associations between phenotypes and genotypes were evaluated with contingency tables. Sensitivity analyses were conducted to confirm the robustness of results, considering potential confounding factors and different treatment response definitions. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated.

RESULTS

Higher expression of PDCD1 was found in RA compared to controls (P < 0.001), with similar PDCD1 polymorphisms in RA and controls. rs36084323 decreased inadequate response to conventional synthetic disease-modifying antirheumatic drugs (OR = 0.37, 95% CI = 0.19-0.72, P = 0.003), and rs41386349 increased rheumatoid factor seropositivity (OR = 11.89, 95% CI = 1.57-89.87, P = 0.003). Sensitivity analysis adjusting for further potential confounders and using different treatment response definition indicated similar results. Additionally, DNA methylation change at regulatory region of PDCD1 was detected in RA (P = 0.036).

CONCLUSION

Altogether, this was the first study to suggest genetic and epigenetic changes of PDCD1 in RA subsets and RA. Independent prospective cohorts are awaited to address the implications of these genetic and epigenetic changes in disease pathogenesis and phenotypes of RA.

Activation of Th lymphocytes alters pattern expression and cellular location of VIP receptors in healthy donors and early arthritis patients

Vasoactive Intestinal Peptide (VIP) is an important immunomodulator of CD4⁺ cells in normal and pathological conditions, which exerts its anti-inflammatory and immunomodulatory actions through VPAC receptors, VPAC₁ and VPAC₂. Only a decrease in the expression of VPAC₁ mRNA on Th cells upon activation has been reported. Thus, the deepening in the knowledge of the behavior of these receptors may contribute to the design of new therapies based on their activation and/or blockade. In this study, we describe the expression pattern, cellular location and functional role of VIP receptors during the activation of human Th cells in healthy conditions and in early arthritis (EA). The protein expression pattern of VPAC₁ did not change with the activation of Th lymphocytes, whereas VPAC₂ was up-regulated. In resting cells, VPAC₁ was located on the plasma membrane and nucleus, whereas it only appeared in the nucleus in activated cells. VPAC₂ was always found in plasma membrane location. VIP receptors signaled through a PKA-dependent pathway in both conditions, and also by a PKA-independent pathway in activated cells. Both receptors exhibit a potent immunomodulatory capacity by controlling the pathogenic profile and the activation markers of Th cells. These results highlight a novel translational view in inflammatory/autoimmune diseases.

Mesenchymal Stem Cells Improve Rheumatoid Arthritis Progression by Controlling Memory T Cell Response

In the last years, mesenchymal stem cell (MSC)-based therapies have become an interesting therapeutic opportunity for the treatment of rheumatoid arthritis (RA) due to their capacity to potently modulate the immune response. RA is a chronic autoimmune inflammatory disorder with an incompletely understood etiology. However, it has been well described that peripheral tolerance defects and the subsequent abnormal infiltration and activation of diverse immune cells into the synovial membrane, are critical for RA development and progression. Moreover, the imbalance between the immune response of pro-inflammatory and anti-inflammatory cells, in particular between memory Th17 and memory regulatory T cells (Treg), respectively, is well admitted to be associated to RA immunopathogenesis. In this context, MSCs, which are able to alter the frequency and function of memory lymphocytes including Th17, follicular helper T (Tfh) cells and gamma delta (γδ) T cells while promoting Treg cell generation, have been proposed as a candidate of choice for RA cell therapy. Indeed, given the plasticity of memory CD4⁺ T cells, it is reasonable to think that MSCs will restore the balance between pro-inflammatory and anti-inflammatory memory T cells populations deregulated in RA leading to prompt their therapeutic function. In the present review, we will discuss the role of memory T cells implicated in RA pathogenesis and the beneficial effects exerted by MSCs on the phenotype and functions of these immune cells abnormally regulated in RA and how this regulation could impact RA progression.

Development of CXCR4 modulators based on the lead compound RB-108

The CXCR4/CXCL12 axis plays prominent roles in tumor metastasis and inflammation. CXCR4 has been shown to be involved in a variety of inflammation-related diseases. Therefore, CXCR4 is a promising potential target to develop novel anti-inflammatory agents. Taking our previously discovered CXCR4 modulator RB-108 as the lead compound, a series of derivatives were synthesized structurally modifying and optimizing the amide and sulfamide side chains. The derivatives successfully maintained potent CXCR4 binding affinity. Furthermore, compounds IIb, IIc, IIIg, IIIj, and IIIm were all efficacious in inhibiting the invasion of CXCR4-positive cells, displaying a much more potent effect than the lead compound RB-108. Notably, compound IIIm significantly decreased carrageenan-induced swollen volume and paw thickness in a mouse paw edema model. More importantly, IIIm exhibited satisfying PK profiles with a half-life of 4.77 h in an SD rat model. In summary, we have developed compound IIIm as a new candidate for further investigation based on the lead compound RB-108.

Beyond Autoantibodies: Biologic Roles of Human Autoreactive B Cells in Rheumatoid Arthritis Revealed by RNA-Sequencing

OBJECTIVE

To obtain the comprehensive transcriptome profile of human citrulline-specific B cells from patients with rheumatoid arthritis (RA).

METHODS

Citrulline- and hemagglutinin-specific B cells were sorted by flow cytometry using peptide-streptavidin conjugates from the peripheral blood of RA patients and healthy individuals. The transcriptome profile of the sorted cells was obtained by RNA-sequencing, and expression of key protein molecules was evaluated by aptamer-based SOMAscan assay and flow cytometry. The ability of these proteins to effect differentiation of osteoclasts and proliferation and migration of synoviocytes was examined by in vitro functional assays.

RESULTS

Citrulline-specific B cells, in comparison to citrulline-negative B cells, from patients with RA differentially expressed the interleukin-15 receptor α (IL-15Rα) gene as well as genes related to protein citrullination and cyclic AMP signaling. In analyses of an independent cohort of cyclic citrullinated peptide-seropositive RA patients, the expression of IL-15Rα protein was enriched in citrulline-specific B cells from the patients' peripheral blood, and surprisingly, all B cells from RA patients were capable of producing the epidermal growth factor ligand amphiregulin (AREG). Production of AREG directly led to increased migration and proliferation of fibroblast-like synoviocytes, and, in combination with anti-citrullinated protein antibodies, led to the increased differentiation of osteoclasts.

CONCLUSION

To the best of our knowledge, this is the first study to document the whole transcriptome profile of autoreactive B cells in any autoimmune disease. These data identify several genes and pathways that may be targeted by repurposing several US Food and Drug Administration-approved drugs, and could serve as the foundation for the comparative assessment of B cell profiles in other autoimmune diseases.

Talk to your gut: the oral-gut microbiome axis and its immunomodulatory role in the etiology of rheumatoid arthritis

Microbial communities inhabiting the human body, collectively called the microbiome, are critical modulators of immunity. This notion is underpinned by associations between changes in the microbiome and particular autoimmune disorders. Specifically, in rheumatoid arthritis, one of the most frequently occurring autoimmune disorders worldwide, changes in the oral and gut microbiomes have been implicated in the loss of tolerance against self-antigens and in increased inflammatory events promoting the damage of joints. In the present review, we highlight recently gained insights in the roles of microbes in the etiology of rheumatoid arthritis. In addition, we address important immunomodulatory processes, including biofilm formation and neutrophil function, which have been implicated in host-microbe interactions relevant for rheumatoid arthritis. Lastly, we present recent advances in the development and evaluation of emerging microbiome-based therapeutic approaches. Altogether, we conclude that the key to uncovering the etiopathogenesis of rheumatoid arthritis will lie in the immunomodulatory functions of the oral and gut microbiomes.

The Role of the CXCL12/CXCR4/ACKR3 Axis in Autoimmune Diseases

Chemokine receptors are members of the G protein-coupled receptor superfamily. These receptors are intimately involved in cell movement, and thus play a critical role in several physiological and pathological situations that require the precise regulation of cell positioning. CXCR4 is one of the most studied chemokine receptors and is involved in many functions beyond leukocyte recruitment. During embryogenesis, it plays essential roles in vascular development, hematopoiesis, cardiogenesis, and nervous system organization. It has been also implicated in tumor progression and autoimmune diseases and, together with CD4, is one of the co-receptors used by the HIV-1 virus to infect immune cells. In contrast to other chemokine receptors that are characterized by ligand promiscuity, CXCR4 has a unique ligand-stromal cell-derived factor-1 (SDF1, CXCL12). However, this ligand also binds ACKR3, an atypical chemokine receptor that modulates CXCR4 functions and is overexpressed in multiple cancer types. The CXCL12/CXCR4/ACKR3 axis constitutes a potential therapeutic target for a wide variety of inflammatory diseases, not only by interfering with cell migration but also by modulating immune responses. Thus far, only one antagonist directed against the ligand-binding site of CXCR4, AMD3100, has demonstrated clinical relevance. Here, we review the role of this ligand and its receptors in different autoimmune diseases.

CXCR4-directed theranostics in oncology and inflammation

Given its prominent role in inflammation and cancer biology, the C-X-C motif chemokine receptor 4 (CXCR4) has gained a lot of attention in the recent years. This review gives a short overview of the physiology and pathology of chemokines and chemokine receptors and then focuses on the current experience of targeting CXCR4, using radiolabeled receptor ligands suitable for positron emission tomography (PET) imaging, in both hematologic and solid malignancy as well as in inflammatory conditions. Additionally, CXCR4-directed endoradiotherapy (ERT) as a new treatment option is discussed.

Sex-based differences in association between circulating T cell subsets and disease activity in untreated early rheumatoid arthritis patients

BACKGROUND

It is not known if sex-based disparities in immunological factors contribute to the disease process in rheumatoid arthritis (RA). Hence, we examined whether circulating T cell subset proportions and their association with disease activity differed in male and female patients with untreated early rheumatoid arthritis (ueRA).

METHODS

Proportions of T cell subsets were analyzed in peripheral blood from 72 ueRA DMARD- and corticosteroid-naïve patients (50 females and 22 males) and in 31 healthy age- and sex-matched controls. Broad analysis of helper and regulatory CD4⁺ T cell subsets was done using flow cytometry. Disease activity in patients was assessed using DAS28, CDAI, swollen joint counts, tender joint counts, CRP, and ESR.

RESULTS

Multivariate factor analyses showed that male and female ueRA patients display distinct profiles of association between disease activity and circulating T cell subset proportions. In male, but not female, ueRA patients Th2 cells showed a positive association with disease activity and correlated significantly with DAS28-ESR, CDAI, and swollen and tender joint counts. Likewise, proportions of non-regulatory CTLA-4⁺ T cells associated positively with disease activity in male patients only, and correlated with DAS28-ESR. In contrast, there was a negative relation between Th1Th17 subset proportions and disease activity in males only. The proportions of Th17 cells correlated positively with DAS28-ESR in males only, while proportions of Th1 cells showed no relation to disease activity in either sex. There were no significant differences in proportions of T cell subsets between the sexes in patients with ueRA.

CONCLUSIONS

Our findings show sex-based differences in the association between T cell subsets and disease activity in ueRA patients, and that Th2 helper T cells may have a role in regulating disease activity in male patients.

CXCR4 blockade decreases CD4+ T cell exhaustion and improves survival in a murine model of polymicrobial sepsis

Sepsis is a dysregulated systemic response to infection involving many inflammatory pathways and the induction of counter-regulatory anti-inflammatory processes that results in a state of immune incompetence and can lead to multi-organ failure. CXCR4 is a chemokine receptor that, following ligation by CXCL12, directs cells to bone marrow niches and also plays an important role in T cell cosignaling and formation of the immunological synapse. Here, we investigated the expression and function of CXCR4 in a murine model of polymicrobial sepsis. Results indicate that CXCR4 is selectively upregulated on naïve CD4⁺ and CD8⁺ T cells and CD4⁺ central memory T cells following the induction of sepsis, and that CXCR4 antagonism resulted in a significant decrease in sepsis-induced mortality. We probed the mechanistic basis for these findings and found that CXCR4 antagonism significantly increased the number of peripheral CD4⁺ and CD8⁺ T cells following sepsis. Moreover, mice treated with the CXCR4 antagonist contained fewer PD-1⁺ LAG-3⁺ 2B4⁺ cells, suggesting that blockade of CXCR4 mitigates CD4⁺ T cell exhaustion during sepsis. Taken together, these results characterize CXCR4 as an important pathway that modulates immune dysfunction and mortality following sepsis, which may hold promise as a target for future therapeutic intervention in septic patients.

Hypomethylation of HLA-DRB1 and its clinical significance in psoriasis

Increasing evidences indicate that the abnormal DNA methylation is involved in the pathogenesis of psoriasis. A number of SNPs in HLA-DRB1 have been found being associated with the risk of psoriasis, however it is unclear that metylation status within HLA-DRB1 in psoriasis. Here, DNA and RNA were obtained from epidermis of 56 patients with plaque psoriasis and 28 healthy volunteers served as the control group. For the first time, we discovered mean methylation rate for HLA-DRB1 is 52.2%, 64.3% and 68.1% in epidermis from psoriatic lesions, psoriatic non-lesions and healthy controls, respectively. HLA-DRB1 methylation in psoriatic lesions is significantly lower than in psoriatic non-lesions (t = 13.077, p < 0.001). However, there is no significant difference for HLA-DRB1 methylation between in psoriatic non-lesions and in healthy controls (t = 1.046, p = 0.299). HLA-DRB1 methylation in psoriatic lesions is negatively correlated to PASI score (r = -0.431, p = 0.001). HLA-DRB1 methylation in psoriatic lesions of the patients with onset age≤18 years is significantly lower than the other patients (t = 3.968, p < 0.001). Meanwhile, HLA-DRB1 mRNA expression is significantly increased in psoriatic lesions comparing to psoriatic non-lesions (t = 12.119, p < 0.001). There are no significant difference for HLA-DRB1 mRNA expression between in psoriatic non-lesions and in healthy controls (t = 1.172, p = 0,245). Moreover, HLA-DRB1 mRNA expression is negatively associated with HLA-DRB1 methylation in psoriatic lesions (r = 0.932, p < 0.001). In conclusions, our results showed hypomethylation of HLA-DRB1 is associated with HLA-DRB1 mRNA expression and severity of the disease, indicating that hypomethylation of HLA-DRB1 may play roles in the pathogenesis of psoriasis.

Chemokine signals are crucial for enhanced homing and differentiation of circulating osteoclast progenitor cells

Background

The peripheral blood (PB) monocyte pool contains osteoclast progenitors (OCPs), which contribute to osteoresorption in inflammatory arthritides and are influenced by the cytokine and chemokine milieu. We aimed to define the importance of chemokine signals for migration and activation of OCPs in rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

Methods

PB and, when applicable, synovial fluid (SF) samples were collected from 129 patients with RA, 53 patients with PsA, and 110 control patients in parallel to clinical parameters of disease activity, autoantibody levels, and applied therapy. Receptors for osteoclastogenic factors (CD115 and receptor activator of nuclear factor-κB [RANK]) and selected chemokines (CC chemokine receptor 1 [CCR1], CCR2, CCR4, CXC chemokine receptor 3 [CXCR3], CXCR4) were determined in an OCP-rich subpopulation (CD3⁻CD19⁻CD56⁻CD11b⁺CD14⁺) by flow cytometry. In parallel, levels of CC chemokine ligand 2 (CCL2), CCL3, CCL4, CCL5, CXC chemokine ligand 9 (CXCL9), CXCL10, and CXCL12 were measured using cytometric bead array or enzyme-linked immunosorbent assay. Sorted OCPs were stimulated in culture by macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand, and they were differentiated into mature osteoclasts that resorb bone. Selected chemokines (CCL2, CCL5, CXCL10, and CXCL12) were tested for their osteoclastogenic and chemotactic effects on circulatory OCPs in vitro.

Results

The OCP population was moderately enlarged among PB cells in RA and correlated with levels of tumor necrosis factor-α (TNF-α), rheumatoid factor, CCL2, and CCL5. Compared with PB, the RANK⁺ subpopulation was expanded in SF and correlated with the number of tender joints. Patients with PsA could be distinguished by increased RANK expression rather than total OCP population. OCPs from patients with arthritis had higher expression of CCR1, CCR2, CCR4, CXCR3, and CXCR4. In parallel, patients with RA had increased levels of CCL2, CCL3, CCL4, CCL5, CXCL9, and CXCL10, with significant elevation in SF vs PB for CXCL10. The subset expressing CXCR4 positively correlated with TNF-α, bone resorption marker, and rheumatoid factor, and it was reduced in patients treated with disease-modifying antirheumatic drugs. The CCR4⁺ subset showed a significant negative trend during anti-TNF treatment. CCL2, CCL5, and CXCL10 had similar osteoclastogenic effects, with CCL5 showing the greatest chemotactic action on OCPs.

Conclusions

In our study, we identified distinct effects of selected chemokines on stimulation of OCP mobilization, tissue homing, and maturation. Novel insights into migratory behaviors and functional properties of circulatory OCPs in response to chemotactic signals could open ways to new therapeutic targets in RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1337-6) contains supplementary material, which is available to authorized users.

Increased serum concentrations of IL-1 beta, IL-21 and Th17 cells in overweight patients with rheumatoid arthritis

Backgrounds

Obesity is associated with worse disease activity and drug responses in patients with rheumatoid arthritis (RA). However, the immunological mechanisms responsible for the relationship between RA and obesity have not yet been clarified in detail. This study aimed to elucidate the immunological mechanisms contributing to the pathogenesis of RA in overweight patients.

Methods

The frequencies of CD4⁺ T cell, B cell and monocyte subsets were analyzed in RA (n = 81) and healthy donors (n = 99) by flow cytometry, and were compared between three groups (body mass index (BMI) <20,  ≥20 to 25, >25). Serum cytokines were measured using multiplex ELISA. Gene expression was analyzed by quantitative PCR. Clinical information was extracted from medical records.

Results

The frequencies of T helper (Th)17 (CD4⁺CD45RA-CXCR5-CXCR3-CCR6⁺) cells and plasmablasts (PB) were significantly increased in patients with RA with BMI >25. Significant correlation was observed between BMI and Th17 cells in patients with RA. No significant differences in cell frequencies between the three BMI groups were observed in the healthy donors. Serum interleukin (IL)-1β and IL-21 significantly correlated with BMI in RA patients. Gene expression patterns in Th17 cells from overweight patients with RA showed the characteristics of pathogenic Th17 cells.

Conclusions

Quantitative and qualitative changes in Th17 cells were characteristic in overweight patients with RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1308-y) contains supplementary material, which is available to authorized users.

Increase in Peripheral Blood Intermediate Monocytes is Associated with the Development of Recent-Onset Type 1 Diabetes Mellitus in Children

Monocytes play important roles in antigen presentation and cytokine production to achieve a proper immune response, and are therefore largely implicated in the development and progression of autoimmune diseases. The aim of this study was to analyze the change in the intermediate (CD14+CD16+) monocyte subset in children with recent-onset type 1 diabetes mellitus (T1DM) and its possible association with clinical parameters reflecting islet β-cell dysfunction. Compared with age- and sex-matched healthy controls, intermediate monocytes were expanded in children with T1DM, which was positively associated with hemoglobin A1C and negatively associated with serum insulin and C-peptide. Interestingly, the intermediate monocytes in T1DM patients expressed higher levels of human leukocyte antigen-DR and CD86, suggesting better antigen presentation capability. Further analysis revealed that the frequency of CD45RO+CD4+ memory T cells was increased in the T1DM patients, and the memory T cell content was well correlated with the increase in intermediate monocytes. These results suggest that expanded intermediate monocytes are a predictive factor for the poor residual islet β-cell function in children with recent-onset T1DM.