Cell-mediated Autoimmune Disease Research Articles

Interferon-α promotes MHC I antigen presentation of islet βcells through STAT1-IRF7 pathway in type 1 diabetes.

Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease. Increased incidence of T1D was reported in patients receiving IFN-α treatment. However, the exact mechanisms of IFN-α that facilitate the pathogenesis of T1D are not fully understood. To explore the mechanism of IFN-α on the immune system and islets, non-obese diabetic (NOD) mice were injected with IFN-α and the progression of autoimmune insulitis was assessed by haematoxylin and eosin (HE) staining, immunohistochemical and flow cytometry analysis. Transcriptional profiling of islets treated with IFN-α was explored by RNA-seq. IFN-α induced antigen presentation was evaluated by qRT-PCR, western blot and immunofluorescence, and key transcription factors were inhibited by small interfering RNAs (siRNAs). Our data show that IFN-α contributed to the progression of autoimmune insulitis in NOD mice by promoting the proliferation of CD8+ T cells. IFN-α upregulated antigen presentation related genes MHC I, TAP1, B2M, PSMB8, NLRC5 and transcriptional regulator STAT1, STAT2, IRF7 at a time and dose-dependent manner. The silence of STAT1 or STAT2 both weakened IFN-α-induced increase of antigen presenting related molecules. IRF7 was also merely influenced by STAT1 silence. The knockdown of IRF7 decreased the IFN-α induced expressions of TAP1, PSMB8 and MHC I and prevented the expression of STAT2 but not STAT1. Our study demonstrated that STAT1-IRF7-MHC I complex axis were crucial for IFN-α signalling in islets, and created positive feedback through IRF7-STAT2 cascade amplifying signals which accelerated the process of T1D.

Individualized regimen of low-dose rituximab monotherapy for new-onset AChR-positive generalized myasthenia gravis.

Generalized AChR-MG is an archetype of B cell-mediated autoimmune disorders, and use of biologic agent rituximab (RTX) for B cell depletion is generally limited to immunosuppressive therapy-refractory cases. However, benefit of RTX monotherapy and individualized regimen with optimal dosage in early stage of new-onset generalized AChR-MG still remains to be elucidated. In this retrospective study, we explore the efficacy and safety of personalized regimen of 100mg low-dose rituximab monotherapy in treating new-onset generalized AChR-MG. Thirteen new-onset generalized AChR-MG patients were enrolled for the study, initiating RTX treatment from November 2017 to August 2020. The individualized low-dose RTX monotherapy protocol consisted of 100mg induction treatment weekly with no more than three circles, followed by reinfusion (100mg once) sequentially according to whether achieving primary endpoint and peripheral CD19 + B-cell repopulation ≥ 1% of total lymphocytes at each visit (every 3months). Outcome measures included MGFA-PIS Minimal Manifestation (MM) or better status (primary endpoint), changes in QMG, MMT, MG-ADL and MGQOL-15 scores (secondary endpoint), as well as cholinesterase inhibitors dosage. All 13 patients achieved the primary endpoint in parallel with significant improvement of QMG, MMT, MG-ADL MGQOL-15 scores, and reduction of cholinesterase inhibitors dose. A total of 52 visits were performed during follow-up, and only 10 assessments presenting peripheral CD19 + B-cell repopulation (≥ 1%) without "MM or better status" were followed by RTX reinfusions (100mg once) for clinical remission. The total dosage of RTX was only 346.15 ± 96.74mg (including 269.23 ± 63.04mg for induction and 76.92 ± 59.91mg for reinfusion), which seemed to be much lower than those dosages used in new-onset generalized AChR-MG as described previously. Moreover, compared with patients without thymoma, thymectomy markedly delayed initiation of RTX for patients with thymoma (log-rank test, p = 0.0002), but the delaying treatments showed no influence on the time for achieving primary outcome (log-rank test, p = 0.2517). Our study firstly showed that individualized regimen of low-dose RTX monotherapy is effective and safe for early treatment of new-onset generalized AChR-MG, and practicable for directing RTX reinfusion and withdrawal. Moreover, the monotherapy protocol was also indicated to be extensively applicable in both new-onset AChR-MG with thymoma (thymectomy) and without thymoma.

Peptide–MHC Complexes: Dressing up to Manipulate T Cells Against Autoimmunity and Cancer

Antigen-specificity of T cells provides important clues to the pathogenesis of T cell-mediated autoimmune diseases and immune-evasion strategies of tumors. Identification of T cell clones involved in autoimmunity or cancer is achieved with soluble peptide-MHC (pMHC) complex multimers. Importantly, these complexes can also be used to manipulate disease-relevant T cells to restore homeostasis of T cell-mediated immune response. While auto-antigen-specific T cells can be deleted or anergized by T cell receptor engagement with cognate pMHC complexes in the absence of costimulation, integration of these complexes in artificial antigen-presenting systems can activate tumor antigen-specific T cells. Here the authors discuss the advancements in pMHC-complex-mediated immunotherapeutic strategies in autoimmunity and cancer and identify the lacunae in these strategies that need to be addressed to facilitate clinical implementation.

Increased plasmablasts enhance T cell-mediated beta cell destruction and promote the development of type 1 diabetes

BackgroundAlthough type 1 diabetes (T1D) is typically described as a T cell-mediated autoimmune disease, increasing evidence for a role of B cells has emerged. However, the pivotal disease-relevant B cell subset and its contribution to islet autoimmunity remain elusive.MethodsThe frequencies and phenotypic characteristics of circulating B cell subsets were analyzed using flow cytometry in individuals with new-onset T1D, long-term T1D, type 2 diabetes, and nondiabetic controls, and also in a prospective cohort of patients receiving mesenchymal stromal cell (MSC) transplantation. NOD mice and adoptive transfer assay were used to dissect the role of the certain B cell subset in disease progression. An in-vitro coculture system of islets with immune cells was established to examine the response against islets and the underlying mechanisms.ResultsWe identified that plasmablasts, a B cell subset at the antibody-secreting stage, were significantly increased and correlated with the deterioration of beta cell function in patients with new-onset T1D. Further, a fall of plasmablast number was associated with the preservation of beta cell function in patients who received MSC transplantation after 3 months of follow-up. Meanwhile, a gradual increase of plasmablasts in pancreatic lymph nodes during the natural progression of insulitis was observed in non-obese diabetic (NOD) mice; adoptive transfer of plasmablasts together with T cells from NOD mice accelerated diabetes onset in NOD/SCID recipients.ConclusionsOur study revealed that plasmablasts may function as antigen-presenting cells and promote the activation and proinflammatory response of CD4+ T cells, further contributing to the T cell-mediated beta cell destruction. Our results provide insights into the pathogenic role of plasmablasts in islet autoimmunity and may offer new translational strategies for inhibiting T1D development.

Antigen-Presenting Cells in Psoriasis.

Psoriasis is classically considered a chronic inflammatory skin disorder, however the identification of autoantigens in its pathogenesis established it as a T cell mediated autoimmune disease. As such professional antigen-presenting cells (APCs) are key players in the development of lesions. APCs in the skin include dendritic cells, Langerhans cells and monocytes/macrophages. In addition, epidermal keratinocytes and dermal mast cells are also endowed with antigen-presenting capacity. Skin APCs have central role in the maintenance of cutaneous immune homeostasis, as well as in initiating and sustaining inflammation under pathologic conditions. In this review we discuss the functional specialization of human skin APCs that promote T cell activation and adaptive immune response during psoriasis initiation and onset.

Effector memory CD4+ T cells induce damaging innate inflammation and autoimmune pathology by engaging CD40 and TNFR on myeloid cells.

Cytokine storm and sterile inflammation are common features of T cell-mediated autoimmune diseases and T cell-targeted cancer immunotherapies. Although blocking individual cytokines can mitigate some pathology, the upstream mechanisms governing overabundant innate inflammatory cytokine production remain unknown. Here, we have identified a critical signaling node that is engaged by effector memory T cells (TEM) to mobilize a broad proinflammatory program in the innate immune system. Cognate interactions between TEM and myeloid cells led to induction of an inflammatory transcriptional profile that was reminiscent, yet entirely independent, of classical pattern recognition receptor (PRR) activation. This PRR-independent "de novo" inflammation was driven by preexisting TEM engagement of both CD40 and tumor necrosis factor receptor (TNFR) on myeloid cells. Cytokine toxicity and autoimmune pathology could be completely rescued by ablating these pathways genetically or pharmacologically in multiple models of T cell-driven inflammation, indicating that TEM instruction of the innate immune system is a primary driver of associated immunopathology. Thus, we have identified a previously unknown trigger of cytokine storm and autoimmune pathology that is amenable to therapeutic interventions.

Inhibiting TLR7 Expression in the Retinal Pigment Epithelium Suppresses Experimental Autoimmune Uveitis.

Experimental autoimmune uveitis (EAU), a model of human uveitis, is an organ-specific, T cell-mediated autoimmune disease. Autoreactive T cells can penetrate the blood-retinal barrier, which is a physical defense composed of tight junction-linked retinal pigment epithelial (RPE) cells. RPE cells serve as antigen-presenting cells (APCs) in the eye since they express MHC class I and II and Toll-like receptors (TLRs). Although previous studies have shown that supplementation with TLR agonists exacerbates uveitis, little is known about how TLR signaling in the RPE contributes to the development of uveitis. In this study, we isolated the RPE from EAU mice, which were induced by active immunization (aEAU) or adoptive transfer of antigen-specific T cells (tEAU). The expression of TLRs on RPE was determined, and both aEAU and tEAU mice exhibited induced tlr7 expression. The TLR7 agonist R848 was shown to induce aggressive disease progression, along with significantly elevated levels of the uveopathogenic cytokine IL-17. Furthermore, not only IL-17 but also R848 appeared to enhance the inflammatory response and to impair the barrier function of the RPE, indicating that TLR7 signaling is involved in the pathogenesis of EAU by affecting the behaviors of the RPE and consequently allowing the infiltration of autoreactive T cells intraocularly. Finally, local application of shRNA against TLR7 delivered by recombinant AAV effectively inhibited disease severity and reduced IFN-γ and IL-17. Our findings highlight an immunomodulatory role of RPE TLR7 in EAU development and provide a potential therapeutic strategy for autoimmune uveitis.

Telitacicept, a novel humanized, recombinant TACI-Fc fusion protein, for the treatment of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, in which aberrant immune cells and proinflammatory mediators act as key players in the pathogenesis of the disease. Telitacicept (RC-18) is a novel, recombinant fusion protein, consisting of transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and the Fc portion of human immunoglobulin G (IgG) (TACI-Fc). It was designed to inhibit the activity of two target cytokines, the B-cell lymphocyte stimulator (BLyS, also known as the B-cell activation factor [BAFF]) and a proliferation-inducing ligand (APRIL), both of which are involved in B cell-mediated autoimmune diseases. In Chinese patients with moderate to severe SLE, subcutaneous telitacicept (80, 160 and 240 mg) in combination with standard therapy was associated with clinical benefit and appeared to be well tolerated. On March 9, 2021, the Chinese National Medical Products Administration (NMPA) granted telitacicept conditional marketing approval for the treatment of adult patients with active, autoantibody-positive SLE. Additionally, on April 15, 2020, the U.S. Food and Drug Administration (FDA) granted fast track designation to telitacicept for the treatment of SLE. Here, we provide a comprehensive review of the preclinical and clinical activity of telitacicept in SLE.

Engineering Cell Therapies for Autoimmune Diseases: From Preclinical to Clinical Proof of Concept.

Autoimmune diseases are caused by a dysfunction of the acquired immune system. In a subset of autoimmune diseases, B cells escaping immune tolerance present autoantigen and produce cytokines and/or autoantibodies, resulting in systemic or organ-specific autoimmunity. Therefore, B cell depletion with monoclonal Abs targeting B cell lineage markers is standard care therapy for several B cell-mediated autoimmune disorders. In the last 5 years, genetically-engineered cellular immunotherapies targeting B cells have shown superior efficacy and long-term remission of B cell malignancies compared to historical clinical outcomes using B cell depletion with monoclonal Ab therapies. This has raised interest in understanding whether similar durable remission could be achieved with use of genetically-engineered cell therapies for autoimmunity. This review will focus on current human clinical trials using engineered cell therapies for B cell-associated autoimmune diseases.

The suppression of Brd4 inhibits peripheral plasma cell differentiation and exhibits therapeutic potential for systemic lupus erythematosus

The mechanisms that control B cell terminal differentiation remain undefined. Here, we investigate the role of bromodomain-containing protein 4 (Brd4) in regulating B cell differentiation and its therapeutic potential for B cell-mediated autoimmune diseases including systemic lupus erythematosus (SLE). We showed that Brd4 inhibitor PFI-1 suppressed plasmablast-mediated plasma cell differentiation in healthy human CD19+ B cells. PFI-1 reduced IgG and IgM secretion in costimulation-induced human B cells. We also observed a reduced percentage of plasma cells in mice with B cell-specific deletion of the Brd4 gene (Brd4flox/floxCD19-cre+). Mechanistically, using the luciferase reporter assay and the chromatin immunoprecipitation, we explored that Brd4 regulates the expression of B lymphocyte-induced maturation protein 1 (BLIMP1), an important transcript factor that is involved in modulation of plasma cell differentiation. Interestingly, PFI-1 decreased the percentages of plasmablasts and plasma cells from patients with SLE. PFI-1 administration reduced the percentages of plasma cells, hypergammaglobulinemia, and attenuated nephritis in MRL/lpr lupus mice. Pristane-injected Brd4flox/floxCD19-cre+ mice exhibited improved nephritis and reduced percentages of plasma cells. These findings suggest an essential factor of Brd4 in regulating plasma cell differentiation. Brd4 inhibition may be a potential strategy for the treatment of B cell-associated autoimmune disorders.

Modulation of Ryanodine Receptors Activity Alters the Course of Experimental Autoimmune Encephalomyelitis in Mice.

Ryanodine receptors (RyRs), the intracellular Ca2+ release channels, are expressed in T lymphocytes and other types of immune cells. Modulation of RyRs has been shown to affect T cell functions in vitro and immune responses in vivo. The effects of modulation of RyRs on the development of autoimmune diseases have not been investigated. Here we studied how modulation of RyRs through administration of RyR inhibitor dantrolene or introducing a gain-of-function RYR1-p.R163C mutation affects clinical progression of experimental autoimmune encephalomyelitis (EAE) in mice, a T cell-mediated autoimmune neuroinflammatory disease. We found that daily intraperitoneal administration of 5 or 10 mg/kg dantrolene beginning at the time of EAE induction significantly reduced the severity of EAE clinical symptoms and dampened inflammation in the spinal cord. The protective effect of dantrolene on EAE was reversible. Dantrolene administration elicited dose-dependent skeletal muscle weakness: mice that received 10 mg/kg dose developed a waddling gait, while 5 mg/kg dantrolene dose administration produced a reduction in four-limb holding impulse values. Mice bearing the gain-of-function RYR1-p.R163C mutation developed the EAE clinical symptoms faster and more severely than wild-type mice. This study demonstrates that RyRs play a significant role in EAE pathogenesis and suggests that inhibition of RyRs with low doses of dantrolene may have a protective effect against autoimmunity and inflammation in humans.

An autoimmune stem-like CD8 T cell population drives type 1 diabetes.

CD8 T cell-mediated autoimmune diseases result from the breakdown of self-tolerance mechanisms in autoreactive CD8 T cells1. How autoimmune T cell populations arise and are sustained, and the molecular programmes defining the autoimmune T cell state, are unknown. In type 1 diabetes, β-cell-specific CD8 T cells destroy insulin-producing β-cells. Here we followed the fate of β-cell-specific CD8 T cells in non-obese diabetic mice throughout the course of type 1 diabetes. We identified a stem-like autoimmune progenitor population in the pancreatic draining lymph node (pLN), which self-renews and gives rise to pLN autoimmune mediators. pLN autoimmune mediators migrate to the pancreas, where they differentiate further and destroy β-cells. Whereas transplantation of as few as 20 autoimmune progenitors induced type 1 diabetes, as many as 100,000 pancreatic autoimmune mediators did not. Pancreatic autoimmune mediators are short-lived, and stem-like autoimmune progenitors must continuously seed the pancreas to sustain β-cell destruction. Single-cell RNA sequencing and clonal analysis revealed that autoimmune CD8 T cells represent unique T cell differentiation states and identified features driving the transition from autoimmune progenitor to autoimmune mediator. Strategies aimed at targeting the stem-like autoimmune progenitor pool could emerge as novel and powerful immunotherapeutic interventions for type 1 diabetes.

P.159: Investigating the Role of Cathepsin L in Islet Graft Rejection

Type 1 diabetes (T1D) is a T cell-mediated autoimmune disorder in which beta-cell specific destruction leads to life-long exogenous insulin dependence. While islet transplantation can restore euglycemia in these patients, both allogeneic and autoimmune rejection of the islet graft pose challenges limiting graft longevity. CD4+ T cells play a major role in driving T1D autoimmune development and islet graft rejection. Recent discovery of hybrid insulin peptides (HIPs), a fusion of insulin peptides with other beta-cell granule containing peptides, were found to be cognate autoantigens for autoreactive CD4+ T cells in mouse models and in patients with T1D. HIPs are formed within the beta-cell during crinophagy, a process of protein degradation or turnover where insulin granules fuse with lysosomes. By reducing the formation of HIPs, autoimmune-mediated islet graft rejection may be delayed. Cathepsin L (CatL) is a lysosomal endopeptidase enzyme involved in protein degradation and is implicated in the generation of HIPs. Non-Obese Diabetic (NOD) mice lacking CatL (NOD.CatL-/-) exhibited a delay in spontaneous T1D development. Immunophenotyping of islet-infiltrating immune cells from NOD.CatL-/- mice displayed reductions in effector CD4+ T cells and tetramer-specific autoreactive BDC-2.5, BDC-6.9, and insulin T cells compared to NOD mice. We hypothesize that islets deficient in CatL will delay immune-mediated rejection due to the absence of antigenic HIPs following transplantation. CatL-deficient islets may improve islet graft survival due to reduced release of antigenic peptides and passenger CD4+ T cells when transplanted into recipient mice. Isolated islets (250 islets/recipient) from NOD.CatL-/-, NOD.CatL+/-, or NOD.Rag mice, were transplanted under the kidney capsule of streptozotocin-treated and spontaneously diabetic NOD mice and monitored for restoration and maintenance of euglycemia. Both NOD.CatL-/- and NOD.CatL+/- islets restored euglycemia similarly as NOD.Rag islets. Future studies will investigate the impact of CatL-deficiency on long-term graft survival and effects on immune cell infiltration and activation. This work was supported by an NIH/NIDDK R01 award (DK099550), JDRF award SRA-2016-270-S-B, JDRF award 2-SRA-2019-692-S-B, NIH/NIDDK R01 award (DK126456), NIH/NIDDK R01 award (DK127497), NIH/NIGMS (T32GM008111) Cell, Molecular, and Developmental Biology T32 training grant.

A CD6-Targeted Antibody-Drug Conjugate As a Potential Therapy for T Cell-Mediated Disorders

INTRODUCTION Pathogenic T cells cause many diseases including most autoimmune diseases and graft-versus-host disease (GVHD). Selectively targeting these pathogenic T cells while sparing the normal T cells and other tissues is a “holy grail” of therapeutics development in modern clinical immunology. So far, pan-immunosuppressive drugs such as corticosteroids are used to treat these patients, with limited efficacy and severe adverse effects. It is also well-established that these pathogenic T cells, whether auto- or alloreactive, proliferate following antigen recognition to cause tissue damage while the other normal T cells remain quiescent. Selectively targeting the proliferating T cells could be an effective strategy to develop new drugs for diseases mediated by the pathogenic T cells.Antibody-drug conjugates (ADCs) are developed by conjugating a potent toxin onto a monoclonal antibody (mAb) specific for a cancer cell surface antigen. Monomethyl auristatin E (MMAE), a synthetic mitotic toxin, is the payload in several FDA-approved ADCs, and it kills the actively dividing cancer cells by blocking the polymerization of tubulin, rapidly inducing apoptosis. These cancer cells and pathogenic T cells have one feature in common-both of them are actively proliferating, thus, this ADC approach proven successful in cancer treatment could be re-purposed to selectively kill pathogenic T cells for the treatment of T cell-mediated diseases.CD6 is a cell surface glycoprotein that is expressed at high levels on all T cells except Treg cells, a small portion of B cells and many human NK cells. CD6 is not detectable on other tissue cells, making it a highly specific target candidate for T cells. We have generated CD6 knockout mice and CD6 humanized mice, and developed anti-CD6 mAbs that treat mouse models T cell-mediated diseases. A CD6-targeted ADC (CD6-ADC) thus might be effective for treating T cell-mediated diseases by selectively eliminating the proliferating pathogenic T cells.METHODS A CD6-ADC was developed by conjugating a latent form of MMAE onto the high-affinity anti-human CD6 mAb. Its potency of selectively killing pathogenic T cells was evaluated in an antigen-specific T cell recall assay with BrdU-incorporation followed by flow cytometric analyses. To determine the toxicity of the CD6-ADC on normal quiescent T cells, naïve CD6 humanized mice were treated with the CD6-ADC or non-binding control ADC (0.5 mg/kg) by intraperitoneal injection, then numbers of circulating T cells were monitored by flow cytometry daily. To evaluate the efficacy of CD6-ADC in treating T cell-mediated autoimmune diseases, the same dose (0.5 mg/kg) of CD6-ADC, or the parental anti-CD6 mAb, or the control ADC was used to treat a model of autoimmune uveitis, and disease severities were assessed by various ocular imaging techniques including indirect ophthalmoscopy, confocal scanning laser ophthalmoscopy and optical coherence tomography. To examine the potential of the CD6-ADC in treating GVHD, the same dose (0.5mg/kg) of CD6-ADC or control ADC was tested in a model of GVHD induced in NSG mice after adoptive transfer of human PBMC. GVHD severities were assessed by flow cytometric analyses of circulating human T cells and by histopathological analyses of different tissues.RESULTS: The CD6-ADC selectively killed antigen-specific proliferating T cells in vitro. Treating naive CD6-humanized mice with this CD6-ADC (0.5 mg/kg) did not significantly eliminate normal T cells in vivo. Furthermore, systemic delivery of the same dose (0.5 mg/kg) of CD6-ADC, but not the anti-CD6 mAb alone nor the control IgG effectively reduced retinal inflammation in a preclinical model of autoimmune uveitis. The same dose of CD6-ADC, but not the control ADC, also effectively depleted activated xenogeneic T cells and prevented the development of GVHD in NSG mice after the adoptive transfer of human PBMC.CONCLUSION: These data indicate that this CD6-ADC holds promise as a new drug for treating diseases in which T cells are integrally involved in the pathogeneses such as GVHD. [Display omitted] DisclosuresLin: Takeda Pharma: Consultancy, Research Funding.

CD6-Targeted Antibody-Drug Conjugate As a Potential Therapeutic Agent for T Cell Lymphomas

Introduction: Peripheral T-cell lymphomas (PTCLs) comprise a subset of blood cancers that are molecularly heterogeneous and often associated with poor survival. While brentuximab vedotin has shown efficacy in CD30-expressing lymphomas such as anaplastic large cell lymphoma, effective targeted therapies for PTCLs are lacking and this represents an unmet medical need.CD6, an established surface marker for T cells, is a key regulator of T cell responses. CD6 has been suggested as a target for treating T cell-mediated autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis. We previously reported that CD6 knockout mice show reduced pathogenic T-cell responses and thus are protected against several models of autoimmune diseases. We also found that CD6 could be targeted therapeutically by anti-CD6 mAbs in these mouse models of autoimmune diseases. Although the distribution of CD6 and its role in regulating normal, non-malignant T-cells has been established, the expression of this marker on PTCL cells and its potential use as a selective targeted therapeutic agent for PTCLs has not been explored.METHODS: To determine the expression profile of CD6 on the malignant T-cells, different specimens including established T-cell lymphoma/leukemia cell lines HH, MOLT-4, HUT-78 and JurkaT-cells, as well as PTCL patient-derived xenografts (PDX) were analyzed for CD6 expression by flow cytometry using UMCD6, a high-affinity anti-human CD6 mAb. Besides, a custom-made tissue microarray containing biopsy samples from different PTCL patients was also evaluated by immunohistochemical staining using the same mAb.A CD6-targeted antibody-drug conjugate (CD6-ADC) was prepared by conjugating monomethyl auristatin E (MMAE), a potent antimitotic toxin successfully used in other FDA-approved ADCs, to UMCD6. Control non-binding ADC was prepared the same way using purified mouse IgGs. The potency of the CD6-ADC of killing PTCL was first evaluated in vitro using HH and HUT78 cells with trypan blue staining. For in vivo treatment studies, NSG mice were subcutaneously inoculated with HH cells, then treated with CD6-ADC or controls at different time points either systemically by intraperitoneal injections or locally by intratumor injections. Treatment efficacies were evaluated by measuring subcutaneous tumor volumes and detecting metastasized tumors in bone marrows, spleens and livers.RESULTS: Our flow cytometric and immunohistochemical staining studies showed that most, if not all the specimens examined expressed high levels of CD6 on the surface, suggesting that CD6 could be a novel therapeutic target for this molecularly heterogeneous blood cancer. Besides, our anti-CD6 mAb, was quickly internalized by PTCL cells after binding to CD6 on their cell surface in an in vitro assay. In contrast to either the parental anti-CD6 mAb, or the non-binding control ADC, the CD6-ADC potently and selectively killed T lymphoma cells in vitro in a time- and concentration-dependent manner. It further prevented the development of tumors in vivo when given 1 day after PTCL cell inoculations. More importantly, systemic or local administration of CD6-ADC, but not the control ADC, significantly shrank existing tumors, reduced tumor metastases from the already developed tumors, and prolonged overall survival in the preclinical mouse model of PTCL without apparent adverse effects.CONCLUSIONS: These results suggest that CD6 is a novel therapeutic target for PTCLs and provide a strong rationale for the further development of CD6-ADC as a promising therapy for patients with this aggressive blood cancer. [Display omitted] DisclosuresHsi: AbbVie Inc, Eli Lilly: Research Funding. Lin: takeda Pharma: Consultancy, Research Funding.

ERAP1 Controls the Autoimmune Response against Melanocytes in Psoriasis by Generating the Melanocyte Autoantigen and Regulating Its Amount for HLA-C*06:02 Presentation.

Autoimmune diseases develop when autoantigens activate previously quiescent self-reactive lymphocytes. Gene-gene interaction between certain HLA class I risk alleles and variants of the endoplasmic reticulum aminopeptidase ERAP1 controls the risk for common immune-mediated diseases, including psoriasis, ankylosing spondylitis, and Behçet disease. The functional mechanisms underlying this statistical association are unknown. In psoriasis, HLA-C*06:02 mediates an autoimmune response against melanocytes by autoantigen presentation. Using various genetically modified cell lines together with an autoreactive psoriatic TCR in a TCR activation assay, we demonstrate in this study that in psoriasis, ERAP1 generates the causative melanocyte autoantigen through trimming N-terminal elongated peptide precursors to the appropriate length for presentation by HLA-C*06:02. An ERAP1 risk haplotype for psoriasis produced the autoantigen much more efficiently and increased HLA-C expression and stimulation of the psoriatic TCR by melanocytes significantly more than a protective haplotype. Compared with the overall HLA class I molecules, cell surface expression of HLA-C decreased significantly more upon ERAP1 knockout. The combined upregulation of ERAP1 and HLA-C on melanocytes in psoriasis lesions emphasizes the pathogenic relevance of their interaction in patients. We conclude that in psoriasis pathogenesis, the increased generation of an ERAP1-dependent autoantigen by an ERAP1 risk haplotype enhances the likelihood that autoantigen presentation by HLA-C*06:02 will exceed the threshold for activation of potentially autoreactive T cells, thereby triggering CD8+ T cell-mediated autoimmune disease. These data identify ERAP1 function as a central checkpoint and promising therapeutic target in psoriasis and possibly other HLA class I-associated diseases with a similar genetic predisposition.

Anti Thymocyte Globulin-Based Treatment for Acquired Bone Marrow Failure in Adults.

Idiopathic acquired aplastic anemia can be successfully treated with Anti Thymocyte Globulin (ATG)-based immune suppressive therapy and is therefore considered a T cell-mediated auto immune disease. Based on this finding, several other forms of idiopathic acquired bone marrow failure are treated with ATG as well. For this review, we extensively searched the present literature for evidence that ATG can lead to enduring remissions in different forms of acquired multi- or single-lineage bone marrow failure. We conclude that ATG-based therapy can lead to an enduring hematopoietic response and increased overall survival (OS) in patients with acquired aplastic aplasia. In patients with hypocellular myelodysplastic syndrome, ATG can lead to a hematological improvement without changing the OS. ATG seems less effective in acquired single-lineage failure diseases like Pure Red Cell Aplasia, Amegakaryocytic Thrombocytopenia and Pure White Cell Aplasia, suggesting a different pathogenesis in these bone marrow failure states compared to aplastic anemia. T cell depletion is hypothesized to play an important role in the beneficial effect of ATG but, as ATG is a mixture of polyclonal antibodies binding to different antigens, other anti-inflammatory or immunomodulatory effects could play a role as well.

Evaluation of serum 25-hydroxy vitamin D levels in alopecia areata of scalp: a cross sectional observational study

<p class="abstract"><strong>Background:</strong> Alopecia areata (AA) is a T cell-mediated autoimmune disorder of anagen hair follicle leading to distressing and relapsing non-scarring hair loss. Vitamin D an immunomodulator plays important role in regulating normal hair cycle. Recent evidence suggests inconsistent association between vitamin D deficiency and alopecia areata.</p><p class="abstract"><strong>Methods:</strong> Hospital-based cross-sectional observational study of forty untreated cases of alopecia areata and forty age and sex-matched healthy controls in 18-45 years of age group recruited from out-patient department. Each patient will undergo a detailed history, clinical examination and SALT (Severity of alopecia tool) scoring. Enhanced chemiluminesence method (Eci) will be used to estimate serum 25-hydroxy vitamin D [25(OH)D].<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean 25(OH)D level in patients of AA was 12.45±4.80 ng/ml (deficient), while that of controls was 33.73±10.02ng/ml (normal). The difference between the levels of 25(OH)D in patients of AA and controls came out to be statistically significant (p≤0.0001). A strong negative correlation was seen between SALT score and 25(OH)D level (-0.32), which was found to be statistically significant (p=0.0462).</p><p class="abstract"><strong>Conclusions:</strong> The present study established that vitamin D levels are either insufficient/deficient in alopecia areata and it correlates negatively with severity of SALT (severity of alopecia tool) score.</p>

Elevated N-Linked Glycosylation of IgG V Regions in Myasthenia Gravis Disease Subtypes.

Elevated N-linked glycosylation of IgG V regions (IgG-VN-Glyc) is an emerging molecular phenotype associated with autoimmune disorders. To test the broader specificity of elevated IgG-VN-Glyc, we studied patients with distinct subtypes of myasthenia gravis (MG), a B cell-mediated autoimmune disease. Our experimental design focused on examining the B cell repertoire and total IgG. It specifically included adaptive immune receptor repertoire sequencing to quantify and characterize N-linked glycosylation sites in the circulating BCR repertoire, proteomics to examine glycosylation patterns of the total circulating IgG, and an exploration of human-derived recombinant autoantibodies, which were studied with mass spectrometry and Ag binding assays to respectively confirm occupation of glycosylation sites and determine whether they alter binding. We found that the frequency of IgG-VN-Glyc motifs was increased in the total BCR repertoire of patients with MG when compared with healthy donors. The elevated frequency was attributed to both biased V gene segment usage and somatic hypermutation. IgG-VN-Glyc could be observed in the total circulating IgG in a subset of patients with MG. Autoantigen binding, by four patient-derived MG autoantigen-specific mAbs with experimentally confirmed presence of IgG-VN-Glyc, was not altered by the glycosylation. Our findings extend prior work on patterns of Ig V region N-linked glycosylation in autoimmunity to MG subtypes.

RNA-Seq based transcriptome analysis in oral lichen planus

ObjectivesOral lichen planus (OLP) is a T cell-mediated autoimmune disease recognized as an oral potential malignant disorder (OPMD) with the precise mechanism unknown. This study focused on the transcriptional profiles of OLP to elucidate its potential pathogenesis.MethodsWe conducted RNA sequencing on matched 6 OLP tissues and 6 normal oral mucosal tissues. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and weighted gene co-expression network analysis (WGCNA) were performed on differentially expressed genes (DEGs). We utilized qRT-PCR to validated the top dysregulated genes and hub genes in another 10 pairs of specimens.ResultsA total of 153 DEGs (p-values< 0.05) were detected from RNA-Seq. According to GO and KEGG analysis, the dysregulated genes were mainly related to T cell related pathway and Wnt signaling. Based on the WGCNA analysis, 5 modules with high intramodular connectivity and hub genes in each module were gained.ConclusionsRNA-Seq and bioinformatic methods offered a valuable understanding of the biological pathways and key genes in the regulation of OLP. The identified DEGs and hub genes categorized into 2 groups including T cell regulation and inflammation and Wnt signaling pathway may serve as potential novel molecular targets for therapy.