Autoimmunity

Chaperones of the class I peptide-loading complex facilitate the constitutive presentation of endogenous antigens on HLA-DP84GGPM87 Publication date: Available online 8 May 2019 Source: Journal of Autoimmunity Author(s): Mark Anczurowski, Kenji Sugata, Yukiko Matsunaga, Yuki Yamashita, Chung-Hsi Wang, Tingxi Guo, Kenji Murata, Hiroshi Saijo, Yuki Kagoya, Kayoko Saso, Marcus O. Butler, Naoto Hirano Abstract Recent work has delineated key differences in the antigen processing and presentation mechanisms underlying HLA-DP alleles encoding glycine at position 84 of the DPβ chain (DP84GGPM87). These DPs are unable to associate with the class II-associated Ii peptide (CLIP) region of the invariant chain (Ii) chaperone early in the endocytic pathway, leading to continuous presentation of endogenous antigens. However, little is known about the chaperone support involved in the loading of these endogenous antigens onto DP molecules. Here, we demonstrate the proteasome and TAP dependency of this pathway and reveal the ability of HLA class I to compete with DP84GGPM87 for the presentation of endogenous antigens, suggesting that shared subcellular machinery may exist between the two classes of HLA. We identify physical interactions of prototypical class I-associated chaperones with numerous DP alleles, including TAP2, tapasin, ERp57, calnexin, and calreticulin, using a conventional immunoprecipitation and immunoblot approach and confirm the existence of these interactions in vivothrough the use of the BioID2 proximal biotinylation system in human cells. Based on immunological assays, we then demonstrate the ability of each of these chaperones to facilitate the presentation of endogenously derived, but not exogenously derived, antigens on DP molecules. Considering previous genetic and clinical studies linking DP84GGPM87 to disease frequency and severity in autoimmune disease, viral infections, and cancer, we suggest that the above chaperones may form the molecular basis of these observable clinical differences through facilitating the presentation of endogenously derived antigens to CD4+ T cells.

The role of protein SUMOylation in rheumatoid arthritis Publication date: Available online 8 May 2019 Source: Journal of Autoimmunity Author(s): Sajad Dehnavi, Mahvash Sadeghi, Thomas P. Johnston, George Barreto, Mojtaba Shohan, Amirhossein Sahebkar Abstract Small ubiquitin-like modifier (SUMO) proteins, as a subgroup of post-translational modifiers, act to change the function of proteins. Through their interactions with different targets, immune pathways, and the responses they elicit, can be affected by these SUMO conjugations. Thus, both a change to protein function and involvement in immune pathways has the potential to promote an efficient immune response to either a pathogenic challenge, or the development of an imbalance that could lead to an autoimmune-based disease. Also, a variety of changes such as mutations and polymorphisms can interfere with common functions of these modifications and move an effective immune response in the direction of an autoimmune disease. The present review discusses the general characteristics of SUMO proteins and focuses on their involvement in rheumatoid arthritis as an autoimmune disease.

Chronic inflammatory demyelinating polyneuropathy as an autoimmune disease Publication date: Available online 6 May 2019 Source: Journal of Autoimmunity Author(s): Yhojan Rodríguez, Nikhil Vatti, Carolina Ramírez-Santana, Christopher Chang, Oscar Mancera-Páez, M. Eric Gershwin, Juan-Manuel Anaya Abstract Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease characterized by neurological symptoms and signs of progressive weakness, paresthesias, and sensory dysfunction. Other symptoms include reduced or absent tendon reflexes, cranial nerve involvement, autonomic symptoms, ataxia, and neuropathic pain. Unlike other autoimmune diseases, CIDP generally affects older individuals and has a male predominance. The onset is generally insidious and can take up to 8 weeks with a relapsing-recovery pattern. Like all autoimmune diseases, the etiology is multifactorial, with both genetic and environmental factors contributing to it. Case reports of CIDP have found associations with multiple pathogenic organisms including Hepatitis B and C viruses, Bartonella henselae, Mycoplasma pneumoniae, Human immunodeficiency virus, Cytomegalovirus and Epstein-Barr virus. Possible antigenic self-targets include myelin protein 0, myelin protein 2, peripheral myelin protein 22, Connexin 32, and myelin basic protein. Antibodies targeting the Ranvier node proteins such as contactin-1, contactin-associated protein 1, and neurofascin 155 have been described. CIDP is treated with rehabilitation and pharmacological modalities. Pharmacological treatments target autoimmune dysfunction and include corticosteroids, intravenous immunoglobulin, subcutaneous immunoglobulin, plasma exchange, immunosuppressive and immunomodulatory agents such as methotrexate, cyclophosphamide, rituximab, and mycophenolate mofetil. Although there are few observational studies and randomized clinical trials with limited evidence supporting the use of immunosuppressive drugs, they are widely used in clinical practice. A comprehensive review of CIDP is presented herein in light of the autoimmune tautology.

Myelin oligodendrocyte glycoprotein revisited—sensitive detection of MOG-specific T-cells in multiple sclerosis Publication date: Available online 1 May 2019 Source: Journal of Autoimmunity Author(s): Mattias Bronge, Sabrina Ruhrmann, Claudia Carvalho-Queiroz, Ola B. Nilsson, Andreas Kaiser, Erik Holmgren, Caterina Macrini, Stephan Winklmeier, Edgar Meinl, Lou Brundin, Mohsen Khademi, Tomas Olsson, Guro Gafvelin, Hans Grönlund Abstract Autoreactive CD4+ T-cells are believed to be a main driver of multiple sclerosis (MS). Myelin oligodendrocyte glycoprotein (MOG) is considered an autoantigen, yet doubted in recent years. The reason is in part due to low frequency and titers of MOG autoantibodies and the challenge to detect MOG-specific T-cells. In this study we aimed to analyze T-cell reactivity and frequency utilizing a novel method for detection of antigen-specific T-cells with bead-bound MOG as stimulant. Peripheral blood mononuclear cells (PBMCs) from natalizumab treated persons with MS (n = 52) and healthy controls (HCs) (n = 24) were analyzed by IFNγ/IL-22/IL-17A FluoroSpot. A higher number of IFNγ (P = 0.001), IL-22 (P = 0.003), IL-17A (P < 0.0001) as well as double and triple cytokine producing MOG-specific T-cells were detected in persons with MS compared to HCs. Of the patients, 46.2–59.6% displayed MOG-reactivity. Depletion of CD4+ T-cells or monocytes or blocking HLA-DR completely eliminated the MOG specific response. Anti-MOG antibodies did not correlate with T-cell MOG-responses. In conclusion, we present a sensitive method to detect circulating autoreactive CD4+ T-cells producing IFNγ, IL-22 or IL-17A using MOG as a model antigen. Further, we demonstrate that MOG-specific T-cells are present in approximately half of persons with MS. Graphical abstract

Primary immunodeficiency and autoimmunity: A comprehensive review Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Laura Amaya-Uribe, Manuel Rojas, Gholamreza Azizi, Juan-Manuel Anaya, M. Eric Gershwin Abstract The primary immunodeficiency diseases (PIDs) include many genetic disorders that affect different components of the innate and adaptive responses. The number of distinct genetic PIDs has increased exponentially with improved methods of detection and advanced laboratory methodology. Patients with PIDs have an increased susceptibility to infectious diseases and non-infectious complications including allergies, malignancies and autoimmune diseases (ADs), the latter being the first manifestation of PIDs in several cases. There are two types of PIDS. Monogenic immunodeficiencies due to mutations in genes involved in immunological tolerance that increase the predisposition to develop autoimmunity including polyautoimmunity, and polygenic immunodeficiencies characterized by a heterogeneous clinical presentation that can be explained by a complex pathophysiology and which may have a multifactorial etiology. The high prevalence of ADs in PIDs demonstrates the intricate relationships between the mechanisms of these two conditions. Defects in central and peripheral tolerance, including mutations in AIRE and T regulatory cells respectively, are thought to be crucial in the development of ADs in these patients. In fact, pathology that leads to PID often also impacts the Treg/Th17 balance that may ease the appearance of a proinflammatory environment, increasing the odds for the development of autoimmunity. Furthermore, the influence of chronic and recurrent infections through molecular mimicry, bystander activation and super antigens activation are supposed to be pivotal for the development of autoimmunity. These multiple mechanisms are associated with diverse clinical subphenotypes that hinders an accurate diagnosis in clinical settings, and in some cases, may delay the selection of suitable pharmacological therapies. Herein, a comprehensively appraisal of the common mechanisms among these conditions, together with clinical pearls for treatment and diagnosis is presented.

Ischemic stroke in giant-cell arteritis: French retrospective study Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Aaron Pariente, Alexis Guédon, Sonia Alamowitch, Sara Thietart, Fabrice Carrat, Stephen Delorme, Jean Capron, Carlotta Cacciatore, Michael Soussan, Azeddine Dellal, Olivier Fain, Arsene Mekinian Abstract Acute cerebrovascular ischemic events are a rare and severe complication of giant cell arteritis (GCA). We aimed to determine the prevalence of GCA-related stroke, the overall survival and the relapse-free survival in patients with GCA. A multicentric retrospective analysis was performed on 129 patients with GCA diagnosed between September 2010 and October 2018 in two University Hospitals. Among 129 GCA patients, 18 (16%) presented an acute ischemic cerebrovascular event. Patients with stroke were older (83 [67–96] years versus 76 [58–96]; p = 0.014) and more frequently males (61% versus 30%; p = 0.014) than those without stroke. The frequency of anterior ischemic optic neuropathy was higher in patients with stroke (n = 6, 33%) than patients without stroke (n = 12, 11%)(p = 0.02). Overall survival was significantly decreased in GCA patients with stroke (4.4 months), comparatively to patients without stroke (221.7 months; log rank test = 0.006). The 3-years relapse-free survival was decreased in patients with stroke (8.42 versus78.0 months; log rank = 0.0001), as well as the time with sustained remission (78 versus 139 months; log rank test = 0.0004). This study shows the prevalence and risk factors of ischemic stroke in GCA.

Autophagy promotes aortic adventitial fibrosis via the IL-6/Jak1 signaling pathway in Takayasu's arteritis Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Rongyi Chen, Ying Sun, Xiaomeng Cui, Zongfei Ji, Xiufang Kong, Sifan Wu, Qingrong Huang, Xiaoming Dai, Si Zhang, Lili Ma, Lindi Jiang Abstract Background Autophagy is a ubiquitous and evolutionarily conserved self-rescue process. Studies have shown that autophagy is involved in the pathogenesis of multiple diseases; however, whether autophagy is associated with the pathogenesis of Takayasu's arteritis (TA), a large vessel idiopathic inflammatory disease characterized by vascular fibrosis, remains unclear. Moreover, although IL-6 is believed to be a direct target for TA treatment, anti-IL-6 treatment could not block TA-associated fibrosis in some cases, which impairs the aortic function of patients and can result in death. Thus, identify the mechanisms associated with TA is extremely important. Based on the relationship between autophagy and IL-6, we investigated the role of autophagy in the vascular fibrosis of TA induced by IL-6. Methods Autophagy proteins (LC3 and Atg3), IL-6, and markers of fibrosis (collagen 1 and α-SMA) were detected in tissues with TA lesions via immunochemistry, immunofluorescence, and Western blot, respectively. Different stages of autophagy were analyzed by the specific inhibitors, 3-methyladenosine (early stage), hydroxychloroquine sulfate (late stage), and bafilomycin A1 (late stage). Autophagosomes were detected using electron microscopy and a viral-vector transfection assay. The fibrosis profiles induced by IL-6-dependent autophagy was assessed with an ELISA. Results The expression of autophagy, IL-6, and fibrosis markers were elevated and correlated with each other in the adventitia tissues of TA patients. Furthermore, exogenous IL-6/IL-6Rα could significantly increase autophagy and fibrosis in vitro. An autophagy inhibitor was found to significantly block both autophagy and fibrosis induced by IL-6. Finally, IL-6 was found to significantly promote autophagy-induced fibrosis through the activation of the Jak1 pathway. Conclusions IL-6-induced autophagy plays an important role in vascular fibrosis of TA. Targeting autophagy pathways might represent a novel therapeutic option for the treatment of TA.

Histologically proven AMA positive primary biliary cholangitis but normal serum alkaline phosphatase: Is alkaline phosphatase truly a surrogate marker? Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Chunyan Sun, Xiao Xiao, Li Yan, Li Sheng, Qixia Wang, Pan Jiang, Min Lian, Yanmei Li, Yiran Wei, Jun Zhang, Yong Chen, Bo Li, You Li, Binyuan Huang, Yikang Li, Yanshen Peng, Xiaoyu Chen, Jingyuan Fang, Dekai Qiu, Jing Hua Abstract Background and aims The most highly directed and specific autoantibody in human immunopathology is the serologic hallmark of primary biliary cholangitis (PBC), antimitochondrial antibodies (AMAs). However the clinical significance of finding a positive AMA, with normal alkaline phosphatase (ALP) remains enigmatic. Methods We took advantage of 169 consecutive outpatients who were identified as having a positive AMA, but normal ALP levels between January 2012 and January 2018. A liver biopsy was performed on 67/169 of these AMA positive normal ALP patients. Results In all 169 patients we reconfirmed the AMA and also performed anti-gp210 and anti-sp100, liver stiffness (LSM) assessed by vibration-controlled transient elastography (VCTE), an abdominal computed tomography (CT) scan, and either a magnetic resonance imaging (MRI) or ultrasound. The liver biopsies were reviewed by two unbiased observers. 87.6% of the 169 patients were females with a mean age of 46; the median AMA titer 1:320; an elevated serum IgM was found in 53.3%. Importantly, in patients with a liver biopsy, 55（82.1%）out of 67 had varying degrees of cholangitis activity, diagnostic of PBC. Conclusion In patients who were AMA-positive but had normal ALP levels, more than 80% were associated with histological classic PBC. These data emphasize the importance of a positive AMA, even with a normal ALP and also question the role of ALP as a sole surrogate marker of cholangitis.

PAM3 supports the generation of M2-like macrophages from lupus patient monocytes and improves disease outcome in murine lupus Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Begum Horuluoglu, Defne Bayik, Neslihan Kayraklioglu, Emilie Goguet, Mariana J. Kaplan, Dennis M. Klinman Abstract Systematic Lupus Erythematosus (SLE) is an autoimmune syndrome of unclear etiology. While T and B cell abnormalities contribute to disease pathogenesis, recent work suggests that inflammatory M1-like macrophages also play a role. Previous work showed that the TLR2/1 agonist PAM3CSK4 (PAM3) could stimulate normal human monocytes to preferentially differentiate into immunosuppressive M2-like rather than inflammatory M1-like macrophages. This raised the possibility of PAM3 being used to normalize the M1:M2 ratio in SLE. Consistent with that possibility, monocytes from lupus patients differentiated into M2-like macrophages when treated with PAM3 in vitro. Furthermore, lupus-prone NZB x NZW F1 mice responded similarly to weekly PAM3 treatment. Normalization of the M2 macrophage frequency was associated with delayed disease progression, decreased autoantibody and inflammatory cytokine synthesis, reduced proteinuria and prolonged survival in NZB x NZW F1 mice. The ability of PAM3 to bias monocyte differentiation in favor of immunosuppressive macrophages may represent a novel approach to the therapy of SLE.

Elevated autoimmunity in residents living near abandoned uranium mine sites on the Navajo Nation Publication date: May 2019 Source: Journal of Autoimmunity, Volume 99 Author(s): Esther Erdei, Chris Shuey, Bernadette Pacheco, Miranda Cajero, Johnnye Lewis, Robert L. Rubin Abstract Specific autoantibodies were assessed among residents of the Navajo Nation in New Mexico chronically exposed to metal mixtures from uranium mine wastes and in drinking water supplies. Age and the extent of exposure to legacy waste from 100 abandoned uranium mine and mill sites were associated with antibodies to denatured DNA, previously known to be an early indicator of medication-induced autoimmunity. Surprisingly, autoantibodies to native DNA and/or chromatin were also linked to environmental exposure, specifically uranium consumption through drinking water for both men and women, while urinary arsenic was negatively associated with these autoantibodies in women. These findings suggest that contaminants derived from uranium mine waste enhanced development of autoantibodies in some individuals, while arsenic may be globally immunosuppressive with gender-specific effects. Specific autoantibodies may be a sensitive indicator of immune perturbation by environmental toxicants, an adverse effect not considered in current drinking water standards or regulatory risk assessment evaluations.