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Czaja AJ. Incorporating the Molecular Mimicry of Environmental Antigens into the Causality of Autoimmune Hepatitis. Dig Dis Sci 2023:10.1007/s10620-023-07967-5. [PMID: 37160542 PMCID: PMC10169207 DOI: 10.1007/s10620-023-07967-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 05/01/2023] [Indexed: 05/11/2023]
Abstract
Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.
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Affiliation(s)
- Albert J Czaja
- Professor Emeritus of Medicine, Mayo Clinic College of Medicine and Science, 200 First Street SW, Rochester, MN, 55905, USA.
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Rodríguez Y, Rojas M, Gershwin ME, Anaya JM. Tick-borne diseases and autoimmunity: A comprehensive review. J Autoimmun 2018; 88:21-42. [DOI: 10.1016/j.jaut.2017.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022]
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Jain V, Arunkumar A, Kingdon C, Lacerda E, Nacul L. Prevalence of and risk factors for severe cognitive and sleep symptoms in ME/CFS and MS. BMC Neurol 2017. [PMID: 28633629 PMCID: PMC5477754 DOI: 10.1186/s12883-017-0896-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND There are considerable phenotypic and neuroimmune overlaps between myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and multiple sclerosis (MS). While the precise aetiologies of both MS and ME/CFS are unclear, evidence suggests that deterioration in cognitive function is widely prevalent in patients with either condition. Little is known about differing risk factors or exposures, which may lead to severe cognitive or sleep symptoms. This study aims to gauge the extent of cognitive and sleep symptoms in ME/CFS and MS patients participating in the UK ME/CFS Biobank and identify the characteristics of those experiencing severe symptoms. METHODS This was a cross-sectional study of 395 UK ME/CFS Biobank participants, recruited from primary care and the community, using similar standardised protocols, and matched by age, sex and geographical area. Data were collected from participants using a standardized written questionnaire at clinical visits. Cognitive symptoms included problems with short-term memory, attention, and executive function. Sleep symptoms included unrefreshing sleep and poor quality or inadequate duration of sleep. All participants reported symptoms based on an ordinal severity scale. Multivariable logistic regression was carried out in the ME/CFS group to investigate socio-demographic factors associated with severe symptoms. RESULTS All cognitive and sleep symptoms were more prevalent in the ME/CFS group, with 'trouble concentrating' (98.3%) the most commonly reported symptom. Severe symptoms were also more commonly reported in the ME/CFS group, with 55% reporting 'severe, unrefreshing sleep'. Similarly, in the MS group, the most commonly reported severe symptoms were sleep-related. Logistic regression analysis revealed that ME/CFS patients aged over 50 years were more than three times as likely to experience severe symptoms than those younger than 30 (OR 3.23, p = 0.031). Current smoking was associated with severe symptoms, increasing the risk by approximately three times (OR 2.93, p = 0.003) and those with household incomes of more than £15,000 per year were less likely to experience severe symptoms compared to those earning less than this (OR 0.31, p = 0.017). CONCLUSIONS Cognitive and sleep symptoms are more common in ME/CFS patients than in MS patients and healthy controls, providing further support for existing evidence of central nervous system abnormalities in ME/CFS. Our findings suggest that people with ME/CFS who are smokers, or have a low income, are more likely to report severe cognitive and sleep symptoms. Future research should aim to develop strategies to prevent the progression of severe cognitive and sleep symptoms through early interventions that prioritise patients identified as being at highest risk.
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Affiliation(s)
- Vageesh Jain
- Guy's Campus, King's College London School of Medicine, London, SE1 1UL, UK.
| | - Amit Arunkumar
- University of California, San Francisco, School of Medicine, San Francisco, CA, 94143, USA
| | - Caroline Kingdon
- Faculty of Infectious and Tropical Diseases, CURE-ME Team, London School of Hygiene & Tropical Medicine Disability and Eye Health Group, International Centre for Evidence in Disability (ICED, K/490, Keppel St, London, WC1E 7HT, UK
| | - Eliana Lacerda
- Faculty of Infectious and Tropical Diseases, CURE-ME Team, London School of Hygiene & Tropical Medicine Disability and Eye Health Group, International Centre for Evidence in Disability (ICED, K/490, Keppel St, London, WC1E 7HT, UK
| | - Luis Nacul
- Faculty of Infectious and Tropical Diseases, CURE-ME Team, London School of Hygiene & Tropical Medicine Disability and Eye Health Group, International Centre for Evidence in Disability (ICED, K/490, Keppel St, London, WC1E 7HT, UK
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Benros ME, Trabjerg BB, Meier S, Mattheisen M, Mortensen PB, Mors O, Børglum AD, Hougaard DM, Nørgaard-Pedersen B, Nordentoft M, Agerbo E. Influence of Polygenic Risk Scores on the Association Between Infections and Schizophrenia. Biol Psychiatry 2016; 80:609-16. [PMID: 27364036 DOI: 10.1016/j.biopsych.2016.04.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 03/18/2016] [Accepted: 04/12/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Several studies have suggested an important role of infections in the etiology of schizophrenia; however, shared genetic liability toward infections and schizophrenia could influence the association. We therefore investigated the possible effect of polygenic risk scores (PRSs) for schizophrenia on the association between infections and the risk of schizophrenia. METHODS We conducted a nested case-control study on a Danish population-based sample born after 1981 comprising of 1692 cases diagnosed with schizophrenia between 1994 and 2008 and 1724 matched controls. All individuals were linked utilizing nationwide population-based registers with virtually complete registration of all hospital contacts for infections. PRSs were calculated using discovery effect size estimates weights from an independent meta-analysis (34,600 cases and 45,968 control individuals). RESULTS A prior hospital contact with infection had occurred in 41% of the individuals with schizophrenia and increased the incidence rate ratio (IRR) of schizophrenia by 1.43 (95% confidence interval [CI] = 1.22-1.67). Adding PRS, which was robustly associated with schizophrenia (by an IRR of 1.46 [95% CI = 1.34-1.60] per standard deviation of the score), did not alter the association with infections and the increased risk of schizophrenia remained (IRR = 1.41; 95% CI = 1.20-1.66). Furthermore, there were no interactions between PRS and infections on the risk of developing schizophrenia (p = .554). Neither did PRS affect the risk of acquiring infections among patients with schizophrenia (odds ratio = 1.00; 95% CI = 0.89-1.12) nor among controls (odds ratio = 1.09; 95% CI: 0.96-1.24). CONCLUSIONS PRS and a history of infections have independent effects on the risk for schizophrenia, and the common genetic risk measured by PRS did not account for the association with infection in this sample.
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Affiliation(s)
- Michael E Benros
- Mental Health Centre Copenhagen, University of Copenhagen, Faculty of Health Sciences, Copenhagen; National Centre for Register-Based Research, Aarhus University, Aarhus; The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen.
| | - Betina B Trabjerg
- National Centre for Register-Based Research, Aarhus University, Aarhus; The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen
| | - Sandra Meier
- National Centre for Register-Based Research, Aarhus University, Aarhus; The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen
| | - Manuel Mattheisen
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen; Department of Biomedicine and Centre for Integrative Sequencing (iSEQ), Aarhus University, Aarhus
| | - Preben B Mortensen
- National Centre for Register-Based Research, Aarhus University, Aarhus; The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen
| | - Ole Mors
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen; Research Department P, Aarhus University Hospital, Risskov
| | - Anders D Børglum
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen; Department of Biomedicine and Centre for Integrative Sequencing (iSEQ), Aarhus University, Aarhus
| | - David M Hougaard
- Danish Centre for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Bent Nørgaard-Pedersen
- Danish Centre for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Merete Nordentoft
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen
| | - Esben Agerbo
- National Centre for Register-Based Research, Aarhus University, Aarhus; The Lundbeck Foundation Initiative for Integrative Psychiatric Research iPSYCH, Copenhagen; CIRRAU-Centre for Integrated Register-Based Research, Aarhus University, Aarhus
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Paiardini A, Pascarella S. Structural mimicry between SLA/LP and Rickettsia surface antigens as a driver of autoimmune hepatitis: insights from an in silico study. Theor Biol Med Model 2013; 10:25. [PMID: 23575112 PMCID: PMC3636016 DOI: 10.1186/1742-4682-10-25] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 04/07/2013] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Autoimmune hepatitis (AIH) is a chronic, progressive liver disease, characterized by continuing hepatocellular inflammation and necrosis. A subgroup of AIH patients presents specific autoantibodies to soluble liver antigen/liver-pancreas (SLA/LP) protein, which is regarded as a highly specific diagnostic marker. Autoantigenic SLA/LP peptides are targeted by CD4+ T cells, and restricted by the allele HLA-DRB1*03:01, which confers disease susceptibility in Europeans and Americans. A positively charged residue at position 71 has been indicated as critical for AIH susceptibility in all of the HLA alleles identified to date. Though the exact molecular mechanisms underlying pathogenesis of AIH are not clear, molecular mimicry between SLA/LP and viral/bacterial antigens has been invoked. METHODS The immunodominant region of SLA/LP was used as query in databank searches to identify statistically significant similarities with viral/bacterial peptides. Homology modeling and docking was used to investigate the potential interaction of HLA-DRB1*03:01 with the identified peptides. By molecular mechanics means, the interactions and energy of binding at the HLA binding site was also scrutinized. RESULTS A statistically significant structural similarity between the immunodominant regions of SLA/LP and a region of the surface antigen PS 120 from Rickettsia spp. has been detected. The interaction of the SLA/LP autoepitope and the corresponding Rickettsia sequence with the allele HLA-DRB1*03:01 has been simulated. The obtained results predict for both peptides a similar binding mode and affinity to HLA-DRB1*03:01. A "hot spot" of interaction between HLA-DRB1*03:01 and PS 120 is located at the P4 binding pocket, and is represented by a salt bridge involving Lys at position 71 of the HLA protein, and Glu 795 of PS120 peptide. CONCLUSIONS These findings strongly support the notion that a molecular mimicry mechanism can trigger AIH onset. CD4+ T cells recognizing peptides of SLA/LP could indeed cross-react with foreign Rickettsia spp. antigens. Finally, the same analysis suggests a molecular explanation for the importance of position 71 in conferring the susceptibility of the allele HLA-DRB1*03:01 to AIH. The lack of a positive charge at such position could prevent HLA alleles from binding the foreign peptides and triggering the molecular mimicry event.
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Affiliation(s)
- Alessandro Paiardini
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza - Università di Roma, Roma, 00185, Italy
| | - Stefano Pascarella
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza - Università di Roma, Roma, 00185, Italy
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Benros ME, Mortensen PB, Eaton WW. Autoimmune diseases and infections as risk factors for schizophrenia. Ann N Y Acad Sci 2012; 1262:56-66. [PMID: 22823436 DOI: 10.1111/j.1749-6632.2012.06638.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Immunological hypotheses have become increasingly prominent when studying the etiology of schizophrenia. Autoimmune diseases, and especially the number of infections requiring hospitalization, have been identified as significant risk factors for schizophrenia in a dose-response relationship, which seem compatible with an immunological hypothesis for subgroups of patients with schizophrenia. Inflammation and infections may affect the brain through many different pathways that are not necessarily mutually exclusive and can possibly increase the risk of schizophrenia in vulnerable individuals. However, the findings could also be an epiphenomenon and not causal, due to, for instance, common genetic vulnerability, which could be supported by the observations of an increased prevalence of autoimmune diseases and infections in parents of patients with schizophrenia. Nevertheless, autoimmune diseases and infections should be considered in the treatment of individuals with schizophrenia symptoms, and further research is needed of the immune system's possible contributing pathogenic factors in the etiology of schizophrenia.
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Affiliation(s)
- Michael E Benros
- National Center for Register-based Research, Aarhus University, Aarhus, Denmark.
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Park MH, Kwon YJ, Jeong HY, Lee HY, Hwangbo Y, Yoon HJ, Shim SH. Association between Intracellular Infectious Agents and Schizophrenia. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2012; 10:117-23. [PMID: 23430959 PMCID: PMC3569146 DOI: 10.9758/cpn.2012.10.2.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 07/30/2012] [Accepted: 08/01/2012] [Indexed: 12/12/2022]
Abstract
Objective A number of studies have reported association between Toxoplasma gondii (T. gondii) and Chlamydia infection and the risk of schizophrenia. The aim of the present study was to compare the prevalence of T. gondii and Chlamydia infection between the schizophrenia and normal control subjects and to compare the clinical features between seropositive and seronegative schizophrenia patients. Methods The rate of serum reactivity to T. gondii, Chlamydia trachomatis (C. trachomatis), Chlamydia pneumonia in 96 schizophrenia and 50 control subjects was investigated using enzyme-linked immunosorbent assay and indirect fluorescent antibody technique. The clinical symptoms of the schizophrenia patients were scored with Positive and Negative Syndrome Scale and a comparative analysis was carried out. Results A significant positive association between immunoglobulin G (IgG) antibodies to T. gondii and C. trachomatis in schizophrenia was found, and the odds ratio of schizophrenia associated with IgG antibody was found to be 3.22 and 2.86, respectively. The Toxoplasma-seropositive schizophrenia patient had higher score on the negative subscale N1 and N7 and general psychopathology subscale G13, while C. trachomatis-seropositive schizophrenia patient had higher score on the general psychopathology subscale G10. Conclusion The results from the present study suggest significant association between T. gondii, C. trachomatis infection and schizophrenia. In future, further studies are needed to elucidate the correlation between the two types of infection and schizophrenia.
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Affiliation(s)
- Mi-Hee Park
- Department of Psychiatry, Soon Chun Hyang University Cheonan Hospital, Soon Chun Hyang University College of Medicine, Cheonan, Korea
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Fellerhoff B, Wank R. Increased prevalence of Chlamydophila DNA in post-mortem brain frontal cortex from patients with schizophrenia. Schizophr Res 2011; 129:191-5. [PMID: 21546214 DOI: 10.1016/j.schres.2011.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 04/05/2011] [Accepted: 04/14/2011] [Indexed: 01/25/2023]
Abstract
Infection can initiate symptoms of mental illness. It has been shown previously that Chlamydophila DNA is present six times more often in the blood of patients with schizophrenia than in the blood of control individuals. Monocytes, the main targets of Chlamydiaceae infection, are microglia precursors. We identified Chlamydiaceae infection using blinded brain DNA samples derived from the frontal cortex. Using PCR and sequence analysis, we found Chlamydophila DNA to be four times greater in patients with schizophrenia than in controls (schizophrenia: N=34, microbial DNA frequency 23.5%; controls: N=35, microbial DNA frequency 5.7%; P=0.045, OR=5.08). Persistent Chlamydophila-infected microglia or neuronal cells may impair neuronal circuits and thus be a mechanism for causing psychiatric illness in these patients.
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Affiliation(s)
- Barbara Fellerhoff
- Institute of Immunology, University of Munich, Goethestrasse 31, D-80336 Munich, Germany.
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