Hasil untuk "Immunologic diseases. Allergy"

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S2 Open Access 2015
Primary Immunodeficiency Diseases: an Update on the Classification from the International Union of Immunological Societies Expert Committee for Primary Immunodeficiency 2015

C. Picard, W. Al-Herz, A. Bousfiha et al.

We report the updated classification of primary immunodeficiencies compiled by the Primary Immunodeficiency Expert Committee (PID EC) of the International Union of Immunological Societies (IUIS). In the two years since the previous version, 34 new gene defects are reported in this updated version. For each disorder, the key clinical and laboratory features are provided. In this new version we continue to see the increasing overlap between immunodeficiency, as manifested by infection and/or malignancy, and immune dysregulation, as manifested by auto-inflammation, auto-immunity, and/or allergy. There is also an increased number of genetic defects that lead to susceptibility to specific organisms which reflects the finely tuned nature of immune defense systems. This classification is the most up to date catalogue of all known and published primary immunodeficiencies and acts as a current reference of the knowledge of these conditions and is an important aid for the genetic and molecular diagnosis of patients with these rare diseases.

737 sitasi en Medicine, Biology
S2 Open Access 2019
Nickel allergy and allergic contact dermatitis: A clinical review of immunology, epidemiology, exposure, and treatment

M. G. Ahlström, J. P. Thyssen, Michael Wennervaldt et al.

Nickel is the most frequent cause of contact allergy worldwide and has been studied extensively. This clinical review provides an updated overview of the epidemiology, exposure sources, methods for exposure quantification, skin deposition and penetration, immunology, diagnosis, thresholds for sensitization and elicitation, clinical pictures, prevention, and treatment. The implementation of a nickel regulation in Europe led to a decrease in the prevalence of nickel allergy, and changes in the clinical picture and disease severity. Nevertheless, the prevalences of nickel allergy in the European general population are approximately 8% to 19% in adults and 8% to 10% in children and adolescents, with a strong female predominance. Well‐known consumer items such as jewellery and metal in clothing are still the main causes of nickel allergy and dermatitis, although a wide range of items for both private and occupational use may cause dermatitis. Allergic nickel dermatitis may be localized to the nickel exposure site, be more widespread, or present as hand eczema. Today, efficient methods for exposure quantification exist, and new insights regarding associated risk factors and immunological mechanisms underlying the disease have been obtained. Nevertheless, questions remain in relation to the pathogenesis, the persistent high prevalence, and the treatment of severe cases.

259 sitasi en Medicine
DOAJ Open Access 2025
Genomic identification of recipient-derived hepatocytes in liver transplantation: a hypothesis linking graft repopulation to immune tolerance

Seoung Hoon Kim

BackgroundOperational tolerance, defined as stable liver graft function without immunosuppression, has been observed in select transplant recipients. While immune regulatory mechanisms have been implicated, the biological processes underlying tolerance remain incompletely understood. Notably, recipient-derived hepatocytes have been shown to progressively repopulate donor livers, raising the possibility that this histological change may contribute to tolerance induction.HypothesisThis hypothesis suggests that progressive replacement of donor hepatocytes by recipient-derived cells reduces donor alloantigen exposure, thereby attenuating allo-immune responses and enabling stable graft acceptance without pharmacologic immunosuppression. This phenomenon could be detected through Y-chromosome–specific assays in sex-mismatched transplants or via donor-recipient genomic profiling in all cases.Supporting evidenceThe liver’s intrinsic regenerative capacity permits continuous hepatocyte turnover and engraftment of recipient-derived cells, particularly under conditions of chronic low-grade injury. Clinical reports have documented the presence of recipient-derived hepatocytes in liver allografts, and operational tolerance has been associated with decreased donor-derived cell-free DNA and reduced allo-immune activation. Although techniques such as FISH and qPCR targeting the Y-chromosome are effective in sex-mismatched cases, broader applicability requires STR or SNP-based genotyping. Integrating these genetic approaches with hepatocyte-specific methylation or transcriptomic profiling may significantly improve the accuracy and clinical relevance of recipient-derived hepatocyte detection.ImplicationsThis hypothesis, if validated, could shift the conceptual model of transplant tolerance from solely immune regulation to a dynamic process of histological replacement. It may also lead to biomarker-driven strategies for immunosuppression withdrawal support novel diagnostic approaches to confirm operational tolerance in appropriate candidates.

Immunologic diseases. Allergy
DOAJ Open Access 2025
IFN-γ gene polymorphisms +874 T/A and +2109 A/G are associated with the serofast state after early syphilis treatment: a prospective observational study

Konrad Kaminiów, Martyna Kiołbasa, Maciej Pastuszczak

BackgroundIn approximately 20% of patients with early syphilis, the classical serological response pattern is absent following treatment. They experience a serofast state, which manifests as less than a 4-fold decline in non-treponemal titres, without any clinical signs of treatment failure or reinfection. The effectiveness of the immune defense against T. pallidum, as well as its potential failure and the occurrence of the serofast state, depends on the Th1 cellular response, including cytokines such as IFN-γ. The aim of this prospective observational study was to investigate the impact of IFN-γ gene polymorphisms on the occurrence of the serofast state.Materials and methodsA cohort of 97 patients with early syphilis (73.2% secondary syphilis, 26.8% early latent syphilis) and 50 healthy volunteers were enrolled. Two single nucleotide polymorphisms (SNPs) in the IFN-γ gene promoter region, +874 T>A (rs2430561) and +2109 A>G (rs1861494), were analyzed. Serum IFN-γ levels were measured at baseline, prior to treatment. Patients were stratified into serofast (n=18) and serologically cured (n=79) groups.ResultsSerofast patients exhibited significantly lower baseline serum IFN-γ levels compared to the serologically cured group (p=0.01). All healthy subjects had IFN-γ levels below the detection limit. Analysis of IFN-γ gene polymorphisms revealed a significant association with treatment outcomes. The +874 AA and +2109 GG genotypes, associated with low IFN-γ production, were significantly more frequent in serofast patients (p=0.0004 and p=0.002, respectively), with odds ratios (OR) of 7.1 (95% CI: 2.2-23.2) and 5.5 (95% CI: 1.8-17.3), respectively. Additionally, carriers of the +874A/+2109G haplotype were significantly more likely to remain serofast (OR 4.4, p=0.01). Conversely, the +874 TT and +2109 AA genotypes, associated with high IFN-γ production, were significantly linked to serological cure (OR 4.4, p=0.03; OR 4.4, p=0.01). Similarly, the +874T/+2109A haplotype was strongly associated with serological cure (OR 17.9, p<0.0001).DiscussionDistinct IFN-γ polymorphisms and haplotypes are associated with serological outcomes in syphilis. The +874 T>A and +2109 A>G variants influence IFN-γ levels, potentially modulating the immune response and serological recovery. These findings suggest a genetic predisposition underlying serofast syphilis and underscore the importance of personalized approaches in its management.

Immunologic diseases. Allergy
DOAJ Open Access 2024
Comparison of hematopoietic stem cell transplantation and repeated intensified immunosuppressive therapy as second-line treatment for relapsed/refractory severe aplastic anemia

Lining Zhang, Lining Zhang, Jianping Li et al.

The optimal treatment for patients with severe aplastic anemia (SAA) who fail an initial course of antithymocyte globulin (ATG) plus cyclosporine has not yet been established. We compared the effectiveness of allogeneic hematopoietic stem cell transplantation (allo-HSCT) (n = 36) with repeated immunosuppressive therapy (IST) (n = 33) for relapsed/refractory SAA between 2007 and 2022. In the IST group, patients were retreated with ATG (n = 16) or high-dose cyclophosphamide (n = 17). The overall response rate was 57.6% at 6 months and 60.6% at 12 months. In the allo-HSCT group, patients received a transplant from a matched sibling donor (n = 6), matched unrelated donor (n = 7), or haploidentical donor (n = 23). All patients achieved neutrophil engraftment, and there were no cases of primary graft failure. The cumulative incidences (CIs) of grades II–IV and III–IV acute graft-versus-host disease (GVHD) were 36.1% ± 0.7% and 13.9% ± 0.3% at day +100, respectively. The 4-year CI of chronic GVHD (cGVHD) was 36.2% ± 0.7%, with moderate to severe cGVHD at 14.9% ± 0.4%. Compared with IST, HSCT recipients showed much higher hematologic recovery rate at 3, 6, and 12 months (63.9%, 83.3%, and 86.1%, respectively, p < 0.001). The estimated 4-year overall survival (OS) (79.8% ± 6.8% vs. 80.0% ± 7.3%, p = 0.957) was similar; however, the failure-free survival (FFS) was significantly better in the HSCT group (79.8% ± 6.8% vs. 56.6% ± 8.8%, p = 0.049). Of note, children in the HSCT cohort were all alive without treatment failures, exhibiting superior OS (100% vs. 50.0% ± 17.7%, p = 0.004) and FFS (100% vs. 50.0% ± 17.7%, p = 0.004) than children in the IST cohort. Subgroup analysis revealed that younger patients (age ≤ 35 years), especially children, and those with refractory SAA benefited more from HSCT. Therefore, for these patients, salvage HSCT may be more preferable than a second course of IST.

Immunologic diseases. Allergy
DOAJ Open Access 2024
Evaluation of immunophenotypic alterations of peripheral blood lymphocytes and their sub-sets in uncomplicated P. Falciparum infection

Samuel Antwi-Baffour, Benjamin Tetteh Mensah, Simon Aglona Ahiakonu et al.

Abstract Background Malaria is a life-threatening parasitic disease typically transmitted through the bite of an infected Anopheles mosquito. There is ample evidence showing the potential of malaria infection to affect the counts of lymphocyte subpopulations in the peripheral blood, but the extent of alteration might not be consistent in all geographical locations, due to several local factors. Although Ghana is among the malaria-endemic countries, there is currently no available data on the level of alterations that occur in the counts of lymphocyte subpopulations during P. falciparum malaria infection among adults. Aim The study was to determine the immunophenotypic alterations in the level of peripheral blood lymphocytes and their subsets in adults with uncomplicated P. falciparum malaria infection and apparently healthy participants. Methods The study was a cross-sectional comparative study conducted in two municipalities of the Volta region of Ghana. Blood samples were collected from study participants and taken through serology (P. falciparum/Pan Rapid Diagnostic Kits), microscopy (Thick and thin blood films) and Haematological (Flow cytometric and Full blood count) analysis. Results A total of 414 participants, comprising 214 patients with malaria and 200 apparently healthy individuals (controls) were recruited into this study. Parasite density of the malaria patients ranged from 75/µL to 84,364/µL, with a mean of 3,520/µL. It was also observed that the total lymphocytes slightly decreased in the P. falciparum-infected individuals (Mean ± SD: 2.08 ± 4.93 × 109/L) compared to the control group (Mean ± SD: 2.47 ± 0.80 × 109/L). Again, there was a significant moderate positive correlation between parasite density and haematocrit levels (r = 0.321, p < 0.001). Apart from CD45 + T-cells, more people in the control group had normal values for the lymphocyte subsets measured compared to the malaria patients. Conclusions From the results obtained, there was high parasite density among the malaria patients suggestive of high intensity of infection in the case group. The malaria patients again showed considerable haematological alterations in lymphocyte sub-sets and the parasite density appeared to be strongly associated with CD4 + T-cell reduction. Also, the parasite density significantly associated with decreasing haematocrit levels. This indicates that lymphocyte subset enumeration can be used to effectively support malaria diagnosis.

Immunologic diseases. Allergy
S2 Open Access 2021
Allergy to COVID-19 vaccines: A current update

B. Cabanillas, N. Novak

Adverse allergic reactions due to the administration of the vaccines developed for the protection of coronavirus disease 2019 (COVID-19) have been reported since the initiation of the vaccination campaigns. Current analyses provided by the Center for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) in the United States have estimated the rates of anaphylactic reactions in 2.5 and 11.1 per million of mRNA-1273 and BNT162b2 vaccines administered, respectively. Although rather low, such rates could have importance due to the uncommon fact that a large majority of the world population will be subjected to vaccination with the aforementioned vaccines in the following months and vaccination will most likely be necessary every season as for influenza vaccines. Health regulators have advised that any subject with a previous history of allergy to drugs or any component of the vaccines should not be vaccinated, however, certain misunderstanding exists since allergy to specific excipients in drugs and vaccines are in occasions misdiagnosed due to an absence of suspicion to specific excipients as allergenic triggers or due to inaccurate labeling or nomenclature. In this review, we provide an updated revision of the most current data regarding the anaphylactic reactions described for BNT162b2 vaccine, mRNA-1273 vaccine, and AZD1222 vaccine. We extensively describe the different excipients in the vaccines with the potential to elicit systemic allergic reactions such as polyethylene glycol (PEG), polysorbates, tromethamine/trometamol, and others and the possible immunological mechanisms involved.

87 sitasi en Medicine
CrossRef Open Access 2022
Progress in Xenotransplantation: Immunologic Barriers, Advances in Gene Editing, and Successful Tolerance Induction Strategies in Pig-To-Primate Transplantation

Daniel L. Eisenson, Yu Hisadome, Kazuhiko Yamada

Organ transplantation is the most effective treatment for end stage organ failure, but there are not enough organs to meet burgeoning demand. One potential solution to this organ shortage is xenotransplantation using pig tissues. Decades of progress in xenotransplantation, accelerated by the development of rapid genome editing tools, particularly the advent of CRISPR-Cas9 gene editing technologies, have enabled remarkable advances in kidney and heart xenotransplantation in pig-to-nonhuman primates. These breakthroughs in large animal preclinical models laid the foundation for three recent pig-to-human transplants by three different groups: two kidney xenografts in brain dead recipients deemed ineligible for transplant, and one heart xenograft in the first clinical grade study of pig-to-human transplantation. However, despite tremendous progress, recent data including the first clinical case suggest that gene-modification alone will not overcome all xenogeneic immunologic barriers, and thus an active and innovative immunologic strategy is required for successful xenotransplantation. This review highlights xenogeneic immunologic barriers, advances in gene editing, and tolerance-inducing strategies in pig-to-human xenotransplantation.

CrossRef Open Access 2023
A user-centred implementation strategy for tuberculosis contact investigation in Uganda: protocol for a stepped-wedge, cluster-randomised trial

Achilles Katamba, Amanda J Gupta, Patricia Turimumahoro et al.

Abstract Background Tuberculosis(TB) is among the leading causes of infectious death worldwide. Contact investigation is an evidence-based, World Health Organisation-endorsed intervention for timely TB diagnosis, treatment, and prevention but has not been widely and effectively implemented. Methods We are conducting a stepped-wedge, cluster-randomised, hybrid Type III implementation-effectiveness trial comparing a user-centred to a standard strategy for implementing TB contact investigation in 12 healthcare facilities in Uganda. The user-centred strategy consists of several client-focused components including (1) a TB-education booklet, (2) a contact-identification algorithm, (3) an instructional sputum-collection video, and (4) a community-health-rider service to transport clients, CHWs, and sputum samples, along with several healthcare-worker-focused components, including (1) collaborative improvement meetings, (2) regular audit-and-feedback reports, and (3) a digital group-chat application designed to develop a community of practice. Sites will cross-over from the standard to the user-centred strategy in six, eight-week transition steps following a randomly determined site-pairing scheme and timeline. The primary implementation outcome is the proportion of symptomatic close contacts completing TB evaluation within 60 days of TB treatment initiation by the index person with TB. The primary clinical effectiveness outcomes are the proportion of contacts diagnosed with and initiating active TB disease treatment and the proportion initiating TB preventative therapy within 60 days. We will assess outcomes from routine source documents using intention-to-treat analyses. We will also conduct nested mixed-methods studies of implementation fidelity and context and perform cost-effectiveness and impact modelling. The Makerere School of Public Health IRB(#554), the Uganda National Council for Science and Technology(#HS1720ES), and the Yale Institutional Review Board(#2000023199) approved the study and waived informed consent for the main trial implementation-effectiveness outcomes. We will submit results for publication in peer-reviewed journals and disseminate findings to local policymakers and representatives of affected communities. Discussion This pragmatic, quasi-experimental implementation trial will inform efforts to find and prevent undiagnosed persons with TB in high-burden settings using contact investigation. It will also help assess the suitability of human-centred design and communities of practice for tailoring implementation strategies and sustaining evidence-based interventions in low-and-middle-income countries. Trial registration The trial was registered(ClinicalTrials.gov Identifier NCT05640648) on 16 November 2022, after the trial launch on 7 March 2022.

4 sitasi en
DOAJ Open Access 2023
The correlation between human papillomavirus and oral lichen planus: A systematic review of the literature

Farzaneh Agha‐Hosseini, Kimia Hafezi Motlagh

Abstract Introduction Oral lichen planus (OLP) is a chronic inflammatory disorder with cell‐induced immunopathological responses and is considered a potential malignancy disorder in the oral cavity. Due to the high prevalence of OLP as well as the potential for malignancy, human papillomaviruses (HPVs) may play an important role in it. Although previous studies have explored the possible relationship between HPV and OLP, the findings have been conflicting and nonconclusive. This study aims to review the studies that investigated HPV‐16 and HPV‐18 in OLP. Methods and Materials The research protocol followed the Preferred Reporting Items for Systematic Reviews (PRISMA2020) checklist. The online databases Pubmed, Scopus, Embase, Google Scholar, and Cochrane were searched using the following individual keywords: “OLP” OR “Oral Lichen Planus” OR “HPV” OR “Human Papillomavirus.” The search strategy resulted in the selection of 80 articles. The articles were evaluated, and after duplication removal, 53 abstracts were reviewed, resulting in the selection of 25 studies according to inclusion and exclusion criteria. The risk of bias assessment was done by using the Modified Newcastle–Ottawa quality assessment scale. The overall prevalence of HPV in OLP lesions varied from 2.7% to 70%, depending on the type of diagnostic method used. Conclusion Despite the studies conducted on the relationship between OLP and HPV infection, there is still no conclusive evidence that HPV can play a role in the etiopathogenesis of OLP, either in clinical manifestations or in the malignant transformation of lesions.

Immunologic diseases. Allergy
DOAJ Open Access 2023
DNAM-1 chimeric receptor-engineered NK cells: a new frontier for CAR-NK cell-based immunotherapy

Loredana Cifaldi, Ombretta Melaiu, Roberto Giovannoni et al.

DNAM-1 is a major NK cell activating receptor and, together with NKG2D and NCRs, by binding specific ligands, strongly contributes to mediating the killing of tumor or virus-infected cells. DNAM-1 specifically recognizes PVR and Nectin-2 ligands that are expressed on some virus-infected cells and on a broad spectrum of tumor cells of both hematological and solid malignancies. So far, while NK cells engineered for different antigen chimeric receptors (CARs) or chimeric NKG2D receptor have been extensively tested in preclinical and clinical studies, the use of DNAM-1 chimeric receptor-engineered NK cells has been proposed only in our recent proof-of-concept study and deserves further development. The aim of this perspective study is to describe the rationale for using this novel tool as a new anti-cancer immunotherapy.

Immunologic diseases. Allergy
S2 Open Access 2022
Further Understanding of Neuro-Immune Interactions in Allergy: Implications in Pathophysiology and Role in Disease Progression

G. Konstantinou, G. Konstantinou, C. Koulias et al.

Abstract The complicated interaction between the central and the autonomic (sympathetic, parasympathetic, and enteric) nervous systems on the one hand and the immune system and its components, on the other hand, seems to substantially contribute to allergy pathophysiology, uncovering an under-recognized association that could have diagnostic and therapeutic potentials. Neurons connect directly with and regulate the function of many immune cells, including mast cells, the cells that have a leading role in allergic disorders. Proinflammatory mediators such as cytokines, neurotrophins, chemokines, and neuropeptides are released by immune cells, which stimulate sensory neurons. The release of neurotransmitters and neuropeptides caused by the activation of these neurons directly impacts the functional activity of immune cells and vice versa, playing a decisive role in this communication. Successful application of Pavlovian conditioning in allergic disorders supports the existence of a psychoneuroimmunological interplay in classical allergic hypersensitivity reactions. Activation of neuronal homeostatic reflexes, like sneezing in allergic rhinitis, coughing in allergic asthma, and vomiting in food allergy, offers additional evidence of a neuroimmunological interaction that aims to maintain homeostasis. Dysregulation of this interaction may cause overstimulation of the immune system that will produce profound symptoms and exaggerated hemodynamic responses that will lead to severe allergic pathophysiological events, including anaphylaxis. In this article, we have systematically reviewed and discussed the evidence regarding the role of the neuro-immune interactions in common allergic clinical modalities like allergic rhinitis, chronic rhinosinusitis, allergic asthma, food allergy, atopic dermatitis, and urticaria. It is essential to understand unknown – to most of the immunology and allergy experts – neurological networks that not only physiologically cooperate with the immune system to regulate homeostasis but also pathogenetically interact with more or less known immunological pathways, contribute to what is known as neuroimmunological inflammation, and shift homeostasis to instability and disease clinical expression. This understanding will provide recognition of new allergic phenotypes/endotypes and directions to focus on specialized treatments, as the era of personalized patient-centered medicine, is hastening apace.

30 sitasi en Medicine
S2 Open Access 2022
Managing the allergy and asthma epidemic in 2020s—Lessons from the Finnish experience

T. Haahtela, Juha Jantunen, K. Saarinen et al.

In Finland, a systematic public health programme was implemented from 2008 to 2018 to mitigate the burden of allergic disorders by revisiting the prevention strategy. Allergy health and contacts with natural environment were emphasized to promote immunological and psychological resilience instead of poorly justified avoidance. Allergy management practices were improved and low‐valued recommendations for care, for example for food allergy, were revised. Patients and families were empowered to use guided self‐management to proactively stop symptom exacerbations. A professional non‐governmental organization implemented the nationwide education for healthcare and patient NGOs for patients, families and lay public. In healthcare, the work supporting allergic patients and families was organized towards common goals and integrated into everyday work without extra costs. Reaching the predefined goals was followed by employing the national healthcare registers and questionnaire surveys. Governmental bodies contributed with kick‐off funding, which was supplemented by private funding. International collaboration, for example with the European patient organization (EFA), increased awareness of the Finnish action and predisposed it for peer review. The 10‐year results are favourable, patients are less disabled, practices and attitudes in healthcare have changed, and major cost savings have been obtained. Views of the lay public and patients are slow to move, however. Local multidisciplinary allergy teams were set up to continue the activities also after the Programme. Changes in environment and lifestyle in the last 50 years are the main reasons for the allergy rise. The Finnish experience may help to manage allergic diseases, improve nature relatedness in the fast‐urbanizing world, combat nature loss and reduce the disease burden.

27 sitasi en Medicine
S2 Open Access 2022
A comprehensive summary of disease variants implicated in metal allergy

Katharine F. Roach, J. Roberts

ABSTRACT Allergic disease represents one of the most prominent global public health crises of the 21st century. Although many different substances are known to produce hypersensitivity responses, metals constitute one of the major classes of allergens responsible for a disproportionately large segment of the total burden of disease associated with allergy. Some of the most prevalent forms of metal allergy – including allergic contact dermatitis – are well-recognized; however, to our knowledge, a comprehensive review of the many unique disease variants implicated in human cases of metal allergy is not available within the current scientific literature. Consequently, the main goal in composing this review was to (1) generate an up-to-date reference document containing this information to assist in the efforts of lab researchers, clinicians, regulatory toxicologists, industrial hygienists, and other scientists concerned with metal allergy and (2) identify knowledge gaps related to disease. Accordingly, an extensive review of the scientific literature was performed – from which, hundreds of publications describing cases of metal-specific allergic responses in human patients were identified, collected, and analyzed. The information obtained from these articles was then used to compile an exhaustive list of distinctive dermal/ocular, respiratory, gastrointestinal, and systemic hypersensitivity responses associated with metal allergy. Each of these disease variants is discussed briefly within this review, wherein specific metals implicated in each response type are identified, underlying immunological mechanisms are summarized, and major clinical presentations of each reaction are described. Abbreviations: ACD: allergic contact dermatitis, AHR: airway hyperreactivity, ASIA: autoimmune/ autoinflammatory syndrome induced by adjuvants, BAL: bronchoalveolar lavage, CBD: chronic beryllium disease, CTCL: cutaneous T-cell lymphoma, CTL: cytotoxic T-Lymphocyte, DRESS: drug reaction with eosinophilia and systemic symptoms, GERD: gastro-esophageal reflux disease, GI: gastrointestinal, GIP: giant cell interstitial pneumonia, GM-CSF: granulocyte macrophage-colony stimulating factor, HMLD: hard metal lung disease, HMW: high molecular weight, IBS: irritable bowel syndrome, Ig: immunoglobulin, IL: interleukin, LMW: low molecular weight, PAP: pulmonary alveolar proteinosis, PPE: personal protective equipment, PRR: pathogen recognition receptor, SLE: systemic lupus erythematosus, SNAS: systemic nickel allergy syndrome, Th: helper T-cell, UC: ulcerative colitis, UV: ultraviolet.

22 sitasi en Medicine
DOAJ Open Access 2022
Staphylococcal Complement Evasion Protein Sbi Stabilises C3d Dimers by Inducing an N-Terminal Helix Swap

Rhys W. Dunphy, Ayla A. Wahid, Catherine R. Back et al.

Staphylococcus aureus is an opportunistic pathogen that is able to thwart an effective host immune response by producing a range of immune evasion molecules, including S. aureus binder of IgG (Sbi) which interacts directly with the central complement component C3, its fragments and associated regulators. Recently we reported the first structure of a disulfide-linked human C3d17C dimer and highlighted its potential role in modulating B-cell activation. Here we present an X-ray crystal structure of a disulfide-linked human C3d17C dimer, which undergoes a structurally stabilising N-terminal 3D domain swap when in complex with Sbi. These structural studies, in combination with circular dichroism and fluorescence spectroscopic analyses, reveal the mechanism underpinning this unique helix swap event and could explain the origins of a previously discovered N-terminally truncated C3dg dimer isolated from rat serum. Overall, our study unveils a novel staphylococcal complement evasion mechanism which enables the pathogen to harness the ability of dimeric C3d to modulate B-cell activation.

Immunologic diseases. Allergy

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