ResearchPad - autoimmunity https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[OR18-06 Thyroid Function Test Abnormalities Secondary to Immune-Checkpoint Inhibitors: A Marker of Survival?]]> https://www.researchpad.co/article/elastic_article_6826 Immune-checkpoint inhibitors (ICI) are monoclonal antibodies which target molecules to enhance antitumor response. Several adverse events have been described and the major ICI-related endocrinopathies are thyroid dysfunction and hypophysitis. Its occurrence has been associated with increased survival.

A retrospective study of adult patients treated with ICI between March 2014 and September 2019 at an oncologic centre was performed to evaluate the impact of thyroid function test abnormalities (TFTA) in their prognosis. We excluded patients without regular monitoring of thyroid function, with previous thyroid or pituitary disease (including medical and surgical treatments), previous head/neck radiotherapy and who performed only one ICI cycle. Clinical data of all patients were examined independently by two Endocrinologists. Survival analysis was performed using the Kaplan-Meier method. Cox regression was used to evaluate associations between the occurrence of TFTA and the outcome of overall survival (OS). It was adjusted for sex, age, primary neoplasm, tumor staging and ICI. All analyses were performed using IBM-SPSS v.25 and a level of significance α=0.05 was noted.

We included 161 of 205 patients, with a median age of 65 years [Interquartile range (IQR) 15] and 67% male. Most patients had melanoma (52%) and lung cancer (43%). Globally, 86, 59 and 25 patients were under pembrolizumab, nivolumab and ipilimumab, respectively. Median duration of ICI treatment was 4.4 months (IQR 7.7) and median total follow‐up was 11.4 months (IQR 11.2). New onset TFTA was diagnosed in 18% of patients, at median age of 65 years (IQR 20) and 55% male. Almost half (45%) had primary hypothyroidism, 28% had central hypothyroidism and 13.8% had biphasic thyroiditis and thyrotoxicosis, each. Most TFTA (79%) occurred under pembrolizumab and nivolumab. Grade 2 CTCAE was the most frequently reported. None of the events led to ICI suspension.

Patients with TFTA underwent a significant higher number of ICI cycles than control group [median 11 cycles (IQR 20) vs 7 (IQR 11), p=0.017] and had a higher period under ICI (median of 7.6 months (IQR 13.8) vs 4.2 (IQR 7.7), p=0.026). Comparison between TFTA patients and control group did not reveal statistical differences in patients’ age and sex, primary neoplasm, tumor staging and ICI.

Overall survival was significantly higher in patients that developed TFTA during treatment with ICI, comparing to the control group (mean OS 3.62 years vs 1.92 years, p=0.033). The risk of mortality was higher for the control group, approximately 3 times, considering the adjustment for the covariates (HR 2.94, 95%CI=1.18 to 7.34, p=0.021). Overall survival was not affected by the covariates.

Our study shows that patients under ICI that develop primary or central thyroid dysfunction had an improved survival. In these patients, the occurrence of TFTA could be a marker of a better response to ICI.

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<![CDATA[OR18-07 Laser Ablation Versus Radiofrequency Ablation for Benign Non-Functioning Thyroid Nodules: Six-Month Results of a Randomised, Parallel, Open-Label, Trial (Lara Trial)]]> https://www.researchpad.co/article/elastic_article_6777 ABSTRACT

Background: Up to now, there are no direct prospective studies comparing Laser (LA) and radiofrequency ablation (RFA). We aimed to compare, in a head- to-head clinical trial, the efficacy and safety of both techniques in a population affected by solid or predominantly solid benign non-functioning thyroid nodules (BNTN).

Methods. LARA is a six-month, single-use, randomized, superiority, open-label, parallel trial. We enrolled subjects with a solitary BNTN or dominant nodule characterized by pressure symptoms/cosmetic problems or patients without symptoms who experienced a volume increase >20% in one year. Nodules underwent core needle biopsy (CNB) to evaluate the histological architecture. Patients were randomly assigned (1:1) to receive treatment with either LA or RFA. The primary endpoint was to evaluate the difference in nodule volume reduction between the RF and the LA group at six months. Moreover, we aimed to assess the differences between groups in the rate of nodules with greater than 50% base volume reduction (successful rate) at six months after treatment. ClinicalTrials.gov: number NCT02714946.

Findings: From January 2016 to November 2018, 60 patients were randomly assigned (30 participants per group). In the whole study population, the average volume of nodules was 25 ml. The two groups were similar in terms of basal nodule volume, thyroid function, histology, symptoms/cosmetic score and procedure time. At six months, participants in the RFA group showed a reduction volume of 64·3% (95% CI: 57·5% - 71·2%) compared to 53·2% (95% CI: 47·2% - 59·2%) in the LA group (p= 0·015) and this difference was also confirmed in a linear regression model adjusted for age, baseline volume and proportion of cellular component (Laser vs. RFA percent change Delta= -12·8, P=0·018).We have not recorded any significant difference in terms of successful rate at six months after treatment between the two groups (86·7% in the RFA vs 66·7% in the LA, p=0·127). At six months, both symptoms and cosmetic scores improved (compressive symptom score: 2·13 vs 3·9 for RFA, p < 0·001; 2·4 vs. 3·87 for LA, p < 0·001; cosmetic score: 1·65 vs 2·2 for RFA p <0·001, 1·85 vs 2·2 for LA p <0·001) without any statistically significant difference between the two groups. No statistical difference between the two groups was detected at six months as regards the TSH level. High rate of cellularity negatively affects the volume reduction in RFA group (r coefficient -0·41, p=0·034) while histological features did not affect the efficacy of the LA. The adverse event rates were 37% and 43% for RFA and LA, respectively, with no requirement for hospitalization.

Interpretation: Both techniques are very effective in reducing the volume of thyroid nodules. RFA appears to be more effective than LA, but both techniques showed no difference in terms of success rate six months after treatment. The safety of the two techniques is very satisfactory.

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<![CDATA[Systemic Autoimmune Disease Among Adults Exposed to the September 11, 2001 Terrorist Attack]]> https://www.researchpad.co/article/elastic_article_6730 Autoimmune disease is an emerging condition among persons exposed to the September 11, 2001 attack on the World Trade Center (WTC). Components of the dust cloud resulting from the collapse of the WTC have been associated with development of a systemic autoimmune disease, as has posttraumatic stress disorder (PTSD). We undertook this study to determine whether dust exposure and PTSD were associated with an increased risk of systemic autoimmune disease in a 9/11‐exposed cohort.MethodsAmong 43,133 WTC Health Registry enrollees, 2,786 self‐reported having a post‐9/11 systemic autoimmune disease. We obtained informed consent to review medical records to validate systemic autoimmune disease diagnoses for 1,041 enrollees. Diagnoses of systemic autoimmune diseases were confirmed by classification criteria, rheumatologist diagnosis, or having been prescribed systemic autoimmune disease medication. Controls were enrollees who denied having an autoimmune disease diagnosis (n = 37,017). We used multivariable log‐binomial regression to examine the association between multiple 9/11 exposures and risk of post‐9/11 systemic autoimmune disease, stratifying by responders (rescue, recovery, and clean‐up workers) and community members (e.g., residents, area workers).ResultsWe identified 118 persons with systemic autoimmune disease. Rheumatoid arthritis was most frequent (n = 71), followed by Sjӧgren's syndrome (n = 22), systemic lupus erythematosus (n = 20), myositis (n = 9), mixed connective tissue disease (n = 7), and scleroderma (n = 4). Among 9/11 responders, those with intense dust cloud exposure had almost twice the risk of systemic autoimmune disease (adjusted risk ratio 1.86 [95% confidence interval 1.02–3.40]). Community members with PTSD had a nearly 3‐fold increased risk of systemic autoimmune disease.ConclusionIntense dust cloud exposure among responders and PTSD among community members were associated with a statistically significant increased risk of new‐onset systemic autoimmune disease. Clinicians treating 9/11 survivors should be aware of the potential increased risk of systemic autoimmune disease in this population. ]]> <![CDATA[OR18-01 Effect of Teprotumumab on Proptosis Reduction Across Various Demographic Sub-Groups]]> https://www.researchpad.co/article/elastic_article_6179 Introduction: Teprotumumab, an insulin-like growth factor 1 receptor inhibitory monoclonal antibody, was recently shown to significantly reduce proptosis in patients with active, moderate-to-severe thyroid eye disease (TED) in phase 2 and phase 3 clinical trials.1,2 Prior analyses have demonstrated a combined trial proptosis response (≥2 mm reduction) rate of 77.4% in the teprotumumab group and 14.9% in the placebo group after 24 weeks of therapy (p < 0.001).3 The current analysis was performed to investigate whether or not patient demographic characteristics influence the teprotumumab proptosis response.

Methods: Data from two 24-week randomized, double-masked, placebo-controlled, parallel-group, multicenter studies (Phase 2 [NCT01868997], Phase 3 [NCT03298867[) were combined. All patients had active TED associated with Graves’ disease. The study eye designated at baseline manifested more severe TED and a clinical activity score of > 4. Subjects were divided into subgroups based on gender, smoking status, and age at baseline (younger: <65, older: ≥65). The percentage of proptosis (≥2 mm) responders and proptosis change from baseline were examined in each of these subgroups. Because most of both teprotumumab (85%) and placebo (87%) subjects were white, there were insufficient numbers of subjects to examine the effect of race on the teprotumumab proptosis response. All analyses were performed on the intent-to-treat (ITT) population using data from the study eye.

Results: A total of 171 patients comprised the population from the two studies. Eighty-four and 87 patients were randomized to the teprotumumab and placebo groups, respectively, and the treatment groups had balanced baseline characteristics. At week 24, significantly more teprotumumab than placebo patients were proptosis responders in all examined subgroups (male: 73.1% vs. 5.0%, female: 79.3% vs. 17.9%, smokers: 70.0% vs. 23.1%, non-smokers 79.7% vs. 11.5%, younger: 76.1% vs. 16.2%, older: 84.6% vs. 7.7%; all p < 0.001). In continuous variable analyses, the mean proptosis reduction from baseline was also significantly greater at week 24 in teprotumumab-treated patients than placebo patients (male: -3.34 vs. -0.07 mm, female: -3.10 vs. -0.42 mm, smokers: -2.99 vs. -0.72 mm, non-smokers: -3.20 vs. -0.31 mm, younger: -3.10 vs. -0.39 mm, older: -3.55 vs. -0.22 mm; all p < 0.001).

Conclusion: Teprotumumab was effective across subgroups of age, gender, and smoking status in the pooled 24-week clinical trials.

Reference: (1) Smith TJ, et al. N Engl J Med 2017;376:1748-1761. (2) Douglas RS, et al. AACE 2019 late-breaking abstract. (3) Kahaly GJ, et al. Thyroid 2019;29(Suppl1):A-1 [abstract].

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<![CDATA[Monoclonal anti‐dsDNA antibody 2C10 escorts DNA to intracellular DNA sensors in normal mononuclear cells and stimulates secretion of multiple cytokines implicated in lupus pathogenesis]]> https://www.researchpad.co/article/Nfccd15f1-af4c-4e91-a562-9311f5095eaf

Summary

There have been many studies on the mechanisms of internalization of DNA–anti‐DNA immune complexes by cells, including the one used for rheumatoid factor‐expressing mouse B cells. In parallel, studies on the role of intracellular DNA sensors in the pathogenesis of systemic lupus erythematosus (SLE) have been conducted, including the one using a mouse model lacking one of the sensors. These and other data have established a framework for understanding the pathogenic role of anti‐DNA antibodies, but studies on normal cells are limited. Here, we used the monoclonal anti‐dsDNA antibody 2C10, 2‐kbp dsDNA and healthy human peripheral blood mononuclear cells (PBMCs) to test whether and how 2C10 and/or DNA cause pathology in normal cells. We found that on culture with PBMCs, 2C10 preferentially entered monocytes and that DNA enhanced this internalization. In contrast, DNA alone was not significantly internalized by monocytes, but 2C10 facilitated its internalization. This was suppressed by cytochalasin D, but not by methyl‐β‐cyclodextrin, chloroquine or an Fc blocker, suggesting the involvement of macropinocytosis in this process. Internalization of 2C10 and DNA together resulted in production of interferon (IFN)‐α, IFN‐γ, tumor necrosis factor (TNF)‐α, monocyte chemoattractant protein‐1 (MCP‐1), interleukin (IL)‐1β, IL‐6, IL‐10 and IL‐33 by PBMCs. Cytokine production was suppressed by chloroquine and shikonin, but not by RU.521, suggesting dependence on activation of the Toll‐like receptor (TLR)‐9 and absent in melanoma 2 (AIM‐2) pathways. These results established a simple model to demonstrate that anti‐DNA antibodies can cause dysregulation of cytokine network mimicking systemic lupus erythematosus in culture of normal PBMCs, and emphasize again the importance of maintaining anti‐DNA antibodies at low levels by treatment.

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<![CDATA[Secretory antibodies to citrullinated peptides in plasma and saliva from rheumatoid arthritis patients and their unaffected first‐degree relatives]]> https://www.researchpad.co/article/N81e962c3-e86f-453a-9f7b-121dea55daf8

Summary

The aim of this study was to evaluate secretory antibodies to citrullinated proteins (ACPA) in plasma and immunoglobulin (Ig)A ACPA in saliva from patients with rheumatoid arthritis (RA) and their unaffected first‐degree relatives (FDRs). Patients with RA (n = 194) and first‐degree relatives unaffected by RA (n = 191) were recruited for analysis of secretory antibodies to second‐generation cyclic citrullinated peptides (anti‐CCP) in plasma. From a subpopulation (25 RA patients, 21 first‐degree relatives and 11 controls), saliva samples were obtained for IgA anti‐CCP analysis. The presence of secretory ACPA was compared between subject categories, and related to genetic and environmental risk factors. Secretory ACPA occurred in 37 (19%) plasma samples from patients with RA, but only in two (1%) of FDRs. IgA ACPA in saliva was found in three of 25 (12%) patients with RA, but not in any of the 21 FDRs (< 5%). No significant associations were seen between the presence of secretory ACPA and SE or smoking, either among RA patients or among FDRs. Despite occurring in 19% of RA plasma, secretory ACPA was rare in both saliva and plasma among FDRs, even among those positive for conventional ACPA of non‐mucosal origin. Longitudinal studies are warranted to determine whether circulating secretory ACPA occurs before or in parallel with the development of clinical arthritis.

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<![CDATA[Analysis of serum Hsp90 as a potential biomarker of β cell autoimmunity in type 1 diabetes]]> https://www.researchpad.co/article/5c40f77ad5eed0c484386221

Heat shock protein 90 (Hsp90) is a protein chaperone that is upregulated and released from pancreatic β cells under pro-inflammatory conditions. We hypothesized that serum Hsp90 may have utility as a biomarker of type 1 diabetes risk and exhibit elevations before the onset of clinically significant hyperglycemia. To this end, total levels of the alpha cytoplasmic isoform of Hsp90 were assayed in autoantibody-positive progressors to type 1 diabetes using banked serum samples from the TrialNet Pathway to Prevention Cohort that had been collected 12 months prior to diabetes onset, with comparison to age, sex, and BMI-category matched autoantibody-positive nonprogressors and healthy controls. Hsp90 levels were higher in autoantibody-positive progressors and nonprogressors ≤ 18 years of age compared to matched healthy controls. However, Hsp90 levels were not different between progressors and nonprogressors in any age group. Hsp90 was positively correlated with age in control subjects, but this correlation was absent in autoantibody positive individuals. In aggregate these data indicate that elevated Hsp90 levels are present in youth with β cell autoimmunity, but are not able to distinguish youth or adult type 1 diabetes progressors from nonprogressors in samples collected 12 months prior to diabetes development.

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<![CDATA[NKT Cell-TCR Expression Activates Conventional T Cells in Vivo, but Is Largely Dispensable for Mature NKT Cell Biology]]> https://www.researchpad.co/article/5989daaaab0ee8fa60ba8e6d

Natural killer T (NKT) cell development depends on recognition of self-glycolipids via their semi-invariant Vα14i-TCR. However, to what extent TCR-mediated signals determine identity and function of mature NKT cells remains incompletely understood. To address this issue, we developed a mouse strain allowing conditional Vα14i-TCR expression from within the endogenous Tcrα locus. We demonstrate that naïve T cells are activated upon replacement of their endogenous TCR repertoire with Vα14i-restricted TCRs, but they do not differentiate into NKT cells. On the other hand, induced TCR ablation on mature NKT cells did not affect their lineage identity, homeostasis, or innate rapid cytokine secretion abilities. We therefore propose that peripheral NKT cells become unresponsive to and thus are independent of their autoreactive TCR.

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<![CDATA[OR18-03 Functional TSH Receptor Antibodies Are a Biomarker for Graves’ Disease - a Prospective Trial]]> https://www.researchpad.co/article/N123c9423-cdbe-4410-9798-cad6fdf37679 40% inhibition).ResultsForty-four patients responded to MMI of whom 43% had Graves’ orbitopathy (GO) while 56 were non-responders (66% with GO, p<0.01). At baseline, undiluted serum TSAb but not thyroid binding inhibiting immunoglobulins (TBII) differentiated between thyroidal GD only versus GD+GO (p<0.001). Further, at baseline responders demonstrated marked differences in diluted TSAb titers compared with non-responders (p<0.001). All patients with a TSAb dilution titer above three did not respond to MMI treatment. In contrast, TBII dilution titers did not differentiate between responders and non-responders to MMI and serum samples became TBII negative already at low dilutions. During treatment, serum TSAb levels decreased markedly in responders (p<0.001) but increased in non-responders (p<0.01). In contrast, TBII strongly decreased in non-responders (p=0.002). All non-responders at week 24 and/or those who relapsed during the 72-week follow-up were TSAb positive at week 24. A shift from TSAb to TBAb was noted in eight patients during treatment and/or follow-up and led to remission.ConclusionsSerum TSAb levels are a biomarker for and mirror severity of GD. Their increase during MMI treatment is a marker for on-going disease activity. TSAb dilution analysis had additional predictive value. ]]> <![CDATA[OR18-05 Thyroid Hormone Use and Survival among Older Adults - Longitudinal Analysis of the Baltimore Longitudinal Study of Aging (BLSA)]]> https://www.researchpad.co/article/N63d1b875-d427-4949-adc0-20338da190b9 <![CDATA[Autoimmune Disease Classification by Inverse Association with SNP Alleles]]> https://www.researchpad.co/article/5989da7bab0ee8fa60b98a17

With multiple genome-wide association studies (GWAS) performed across autoimmune diseases, there is a great opportunity to study the homogeneity of genetic architectures across autoimmune disease. Previous approaches have been limited in the scope of their analysis and have failed to properly incorporate the direction of allele-specific disease associations for SNPs. In this work, we refine the notion of a genetic variation profile for a given disease to capture strength of association with multiple SNPs in an allele-specific fashion. We apply this method to compare genetic variation profiles of six autoimmune diseases: multiple sclerosis (MS), ankylosing spondylitis (AS), autoimmune thyroid disease (ATD), rheumatoid arthritis (RA), Crohn's disease (CD), and type 1 diabetes (T1D), as well as five non-autoimmune diseases. We quantify pair-wise relationships between these diseases and find two broad clusters of autoimmune disease where SNPs that make an individual susceptible to one class of autoimmune disease also protect from diseases in the other autoimmune class. We find that RA and AS form one such class, and MS and ATD another. We identify specific SNPs and genes with opposite risk profiles for these two classes. We furthermore explore individual SNPs that play an important role in defining similarities and differences between disease pairs. We present a novel, systematic, cross-platform approach to identify allele-specific relationships between disease pairs based on genetic variation as well as the individual SNPs which drive the relationships. While recognizing similarities between diseases might lead to identifying novel treatment options, detecting differences between diseases previously thought to be similar may point to key novel disease-specific genes and pathways.

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<![CDATA[Plasmin Plays an Essential Role in Amplification of Psoriasiform Skin Inflammation in Mice]]> https://www.researchpad.co/article/5989da93ab0ee8fa60ba0c35

Background

Although increased levels of plasminogen activators have been found in psoriatic lesions, the role of plasmin converted from plasminogen by plasminogen activators in pathogenesis of psoriasis has not been investigated.

Methodology/Principal Findings

Here we examined the contribution of plasmin to amplification of inflammation in patients with psoriasis. We found that plasminogen was diminished, but that the amount and activity of its converted product plasmin were markedly increased in psoriasis. Moreover, annexin II, a receptor for plasmin was dramatically increased in both dermis and epidermis in psoriasis. Plasmin at sites of inflammation was pro-inflammatory, eliciting production of inflammatory factors, including CC chemokine ligand 20 (CCL20) and interleukin-23 (IL-23), that was mediated by the nuclear factor-kappaB (NF-κB) signaling pathway and that had an essential role in the recruitment and activation of pathogenic C-C chemokine receptor type 6 (CCR6)+ T cells. Moreover, intradermal injection of plasmin or plasmin together with recombinant monocyte/macrophage chemotactic protein-1 (MCP-1) resulted in induction of psoriasiform skin inflammation around the injection sites with several aspects of human psoriasis in mice.

Conclusions/Significance

Plasmin converted from plasminogen by plasminogen activators plays an essential role in amplification of psoriasiform skin inflammation in mice, and targeting plasmin receptor - annexin II - may harbor therapeutic potential for the treatment of human psoriasis.

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<![CDATA[Monitoring the T-Cell Receptor Repertoire at Single-Clone Resolution]]> https://www.researchpad.co/article/5989d9f0ab0ee8fa60b6e3ff

The adaptive immune system recognizes billions of unique antigens using highly variable T-cell receptors. The αβ T-cell receptor repertoire includes an estimated 106 different rearranged β chains per individual. This paper describes a novel micro-array based method that monitors the β chain repertoire with a resolution of a single T-cell clone. These T-arrays are quantitative and detect T-cell clones at a frequency of less than one T cell in a million, which is 2 logs more sensitive than spectratyping (immunoscope), the current standard in repertoire analysis. Using T-arrays we detected CMV-specific CD4+ and CD8+ T-cell clones that expanded early after viral antigen stimulation in vitro and in vivo. This approach will be useful in monitoring individual T-cell clones in diverse experimental settings, and in identification of T-cell clones associated with infectious disease, autoimmune disease and cancer.

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<![CDATA[Loss of P2X7 Receptor Plasma Membrane Expression and Function in Pathogenic B220+ Double-Negative T Lymphocytes of Autoimmune MRL/lpr Mice]]> https://www.researchpad.co/article/5989da6dab0ee8fa60b93aaf

Lupus is a chronic inflammatory autoimmune disease influenced by multiple genetic loci including Fas Ligand (FasL) and P2X7 receptor (P2X7R). The Fas/Fas Ligand apoptotic pathway is critical for immune homeostasis and peripheral tolerance. Normal effector T lymphocytes up-regulate the transmembrane tyrosine phosphatase B220 before undergoing apoptosis. Fas-deficient MRL/lpr mice (lpr mutation) exhibit lupus and lymphoproliferative syndromes due to the massive accumulation of B220+ CD4CD8 (DN) T lymphocytes. The precise ontogeny of B220+ DN T cells is unknown. B220+ DN T lymphocytes could be derived from effector CD4+ and CD8+ T lymphocytes, which have not undergone activation-induced cell death due to inactivation of Fas, or from a special cell lineage. P2X7R is an extracellular ATP-gated cell membrane receptor involved in the release of proinflammatory cytokines and TNFR1/Fas-independent cell death. P2X7R also regulate early signaling events involved in T-cell activation. We show herein that MRL/lpr mice carry a P2X7R allele, which confers a high sensitivity to ATP. However, during aging, the MRL/lpr T-cell population exhibits a drastically reduced sensitivity to ATP- or NAD-mediated stimulation of P2X7R, which parallels the increase in B220+ DN T-cell numbers in lymphoid organs. Importantly, we found that this B220+ DN T-cell subpopulation has a defect in P2X7R-mediated responses. The few B220+ T cells observed in normal MRL+/+ and C57BL/6 mice are also resistant to ATP or NAD treatment. Unexpectedly, while P2X7R mRNA and proteins are present inside of B220+ T cells, P2X7R are undetectable on the plasma membrane of these T cells. Our results prompt the conclusion that cell surface expression of B220 strongly correlates with the negative regulation of the P2X7R pathway in T cells.

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<![CDATA[Inhibition of Effector Function but Not T Cell Activation and Increase in FoxP3 Expression in T Cells Differentiated in the Presence of PP14]]> https://www.researchpad.co/article/5989da2fab0ee8fa60b83c3d

Background

T-helper polarization of naïve T cells is determined by a complex mechanism that involves many factors, eventually leading to activation of Th1, Th2, or Th17 responses or alternatively the generation of regulatory T cells. Placental Protein 14 (PP14) is a 28 kDa glycoprotein highly secreted in early pregnancy that is able to desensitize T cell receptor (TCR) signaling and modulate T cell activation.

Methodology/Principal Findings

Prolonged antigen-specific stimulation of T cells in the presence of PP14 resulted in an impaired secretion of IFN-γ, IL-5 and IL-17 upon restimulation, although the cells proliferated and expressed activation markers. Furthermore, the generation of regulatory CD4+CD25highFoxp3+ T cells was induced in the presence of PP14, in both antigen-specific as well as polyclonal stimulation. In accordance with previous reports, we found that the induction of FoxP3 expression by PP14 is accompanied by down regulation of the PI3K-mTOR signaling pathway.

Conclusions/Significance

These data suggest that PP14 arrests T cells in a unique activated state that is not accompanied with the acquisition of effector function, together with promoting the generation of regulatory T cells. Taken together, our results may elucidate the role of PP14 in supporting immune tolerance in pregnancy by reducing T cell effector functions along with augmenting Treg differentiation.

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<![CDATA[PI3Kγ Drives Priming and Survival of Autoreactive CD4+ T Cells during Experimental Autoimmune Encephalomyelitis]]> https://www.researchpad.co/article/5989da85ab0ee8fa60b9bfec

The class IB phosphoinositide 3-kinase gamma enzyme complex (PI3Kγ) functions in multiple signaling pathways involved in leukocyte activation and migration, making it an attractive target in complex human inflammatory diseases including MS. Here, using pik3cg−/− mice and a selective PI3Kγ inhibitor, we show that PI3Kγ promotes development of experimental autoimmune encephalomyelitis (EAE). In pik3cg−/− mice, EAE is markedly suppressed and fewer leukocytes including CD4+ and CD8+ T cells, granulocytes and mononuclear phagocytes infiltrate the CNS. CD4+ T cell priming in secondary lymphoid organs is reduced in pik3cg−/− mice following immunisation. This is attributable to defects in DC migration concomitant with a failure of full T cell activation following TCR ligation in the absence of p110γ. Together, this results in suppressed autoreactive T cell responses in pik3cg−/− mice, with more CD4+ T cells undergoing apoptosis and fewer cytokine-producing Th1 and Th17 cells in lymphoid organs and the CNS. When administered from onset of EAE, the orally active PI3Kγ inhibitor AS605240 caused inhibition and reversal of clinical disease, and demyelination and cellular pathology in the CNS was reduced. These results strongly suggest that inhibitors of PI3Kγ may be useful therapeutics for MS.

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<![CDATA[Autoantibody Epitope Spreading in the Pre-Clinical Phase Predicts Progression to Rheumatoid Arthritis]]> https://www.researchpad.co/article/5989d9f5ab0ee8fa60b6fcc6

Rheumatoid arthritis (RA) is a prototypical autoimmune arthritis affecting nearly 1% of the world population and is a significant cause of worldwide disability. Though prior studies have demonstrated the appearance of RA-related autoantibodies years before the onset of clinical RA, the pattern of immunologic events preceding the development of RA remains unclear. To characterize the evolution of the autoantibody response in the preclinical phase of RA, we used a novel multiplex autoantigen array to evaluate development of the anti-citrullinated protein antibodies (ACPA) and to determine if epitope spread correlates with rise in serum cytokines and imminent onset of clinical RA. To do so, we utilized a cohort of 81 patients with clinical RA for whom stored serum was available from 1–12 years prior to disease onset. We evaluated the accumulation of ACPA subtypes over time and correlated this accumulation with elevations in serum cytokines. We then used logistic regression to identify a profile of biomarkers which predicts the imminent onset of clinical RA (defined as within 2 years of testing). We observed a time-dependent expansion of ACPA specificity with the number of ACPA subtypes. At the earliest timepoints, we found autoantibodies targeting several innate immune ligands including citrullinated histones, fibrinogen, and biglycan, thus providing insights into the earliest autoantigen targets and potential mechanisms underlying the onset and development of autoimmunity in RA. Additionally, expansion of the ACPA response strongly predicted elevations in many inflammatory cytokines including TNF-α, IL-6, IL-12p70, and IFN-γ. Thus, we observe that the preclinical phase of RA is characterized by an accumulation of multiple autoantibody specificities reflecting the process of epitope spread. Epitope expansion is closely correlated with the appearance of preclinical inflammation, and we identify a biomarker profile including autoantibodies and cytokines which predicts the imminent onset of clinical arthritis.

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<![CDATA[The Dynamic Processing of CD46 Intracellular Domains Provides a Molecular Rheostat for T Cell Activation]]> https://www.researchpad.co/article/5989daebab0ee8fa60bbf199

Background

Adequate termination of an immune response is as important as the induction of an appropriate response. CD46, a regulator of complement activity, promotes T cell activation and differentiation towards a regulatory Tr1 phenotype. This Tr1 differentiation pathway is defective in patients with MS, asthma and rheumatoid arthritis, underlying its importance in controlling T cell function and the need to understand its regulatory mechanisms. CD46 has two cytoplasmic tails, Cyt1 and Cyt2, derived from alternative splicing, which are co-expressed in all nucleated human cells. The regulation of their expression and precise functions in regulating human T cell activation has not been fully elucidated.

Methodology/Principal Findings

Here, we first report the novel role of CD46 in terminating T cell activation. Second, we demonstrate that its functions as an activator and inhibitor of T cell responses are mediated through the temporal processing of its cytoplasmic tails. Cyt1 processing is required to turn T cell activation on, while processing of Cyt2 switches T cell activation off, as demonstrated by proliferation, CD25 expression and cytokine secretion. Both tails require processing by Presenilin/γSecretase (P/γS) to exert these functions. This was confirmed by expressing wild-type Cyt1 and Cyt2 tails and uncleavable mutant tails in primary T cells. The role of CD46 tails was also demonstrated with T cells expressing CD19 ectodomain-CD46 C-Terminal Fragment (CTF) fusions, which allowed specific triggering of each tail individually.

Conclusions/Significance

We conclude that CD46 acts as a molecular rheostat to control human T cell activation through the regulation of processing of its cytoplasmic tails.

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<![CDATA[Tuftsin Promotes an Anti-Inflammatory Switch and Attenuates Symptoms in Experimental Autoimmune Encephalomyelitis]]> https://www.researchpad.co/article/5989db06ab0ee8fa60bc8722

Multiple sclerosis (MS) is a demyelinating autoimmune disease mediated by infiltration of T cells into the central nervous system after compromise of the blood-brain barrier. We have previously shown that administration of tuftsin, a macrophage/microglial activator, dramatically improves the clinical course of experimental autoimmune encephalomyelitis (EAE), a well-established animal model for MS. Tuftsin administration correlates with upregulation of the immunosuppressive Helper-2 Tcell (Th2) cytokine transcription factor GATA-3. We now show that tuftsin-mediated microglial activation results in shifting microglia to an anti-inflammatory phenotype. Moreover, the T cell phenotype is shifted towards immunoprotection after exposure to tuftsin-treated activated microglia; specifically, downregulation of pro-inflammatory Th1 responses is triggered in conjunction with upregulation of Th2-specific responses and expansion of immunosuppressive regulatory T cells (Tregs). Finally, tuftsin-shifted T cells, delivered into animals via adoptive transfer, reverse the pathology observed in mice with established EAE. Taken together, our findings demonstrate that tuftsin decreases the proinflammatory environment of EAE and may represent a therapeutic opportunity for treatment of MS.

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<![CDATA[Treatment with the Antipsychotic Agent, Risperidone, Reduces Disease Severity in Experimental Autoimmune Encephalomyelitis]]> https://www.researchpad.co/article/5989daeaab0ee8fa60bbec04

Recent studies have demonstrated that atypical antipsychotic agents, which are known to antagonize dopamine D2 and serotonin 5-HT2a receptors, have immunomodulatory properties. Given the potential of these drugs to modulate the immune system both peripherally and within the central nervous system, we investigated the ability of the atypical anti-psychotic agent, risperidone, to modify disease in the animal model of multiple sclerosis (MS)4, experimental autoimune encephalomyelitis (EAE). We found that chronic oral administration of risperidone dose-dependently reduced the severity of disease and decreased both the size and number of spinal cord lesions. Furthermore, risperidone treatment substantially reduced antigen-specific interleukin (IL)-17a, IL-2, and IL-4 but not interferon (IFN)-γ production by splenocytes at peak disease and using an in vitro model, we show that treatment of macrophages with risperidone alters their ability to bias naïve T cells. Another atypical antipsychotic agent, clozapine, showed a similar ability to modify macrophages in vitro and to reduce disease in the EAE model but this effect was not due to antagonism of the type 1 or type 2 dopamine receptors alone. Finally, we found that while risperidone treatment had little effect on the in vivo activation of splenic macrophages during EAE, it significantly reduced the activation of microglia and macrophages in the central nervous system. Together these studies indicate that atypical antipsychotic agents like risperidone are effective immunomodulatory agents with the potential to treat immune-mediated diseases such as MS.

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