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Sneha Muppala R, Basavaraj V. Role of C4d immunohistochemical marker in the diagnosis of bullous pemphigoid: A cross-sectional study. Indian J Dermatol Venereol Leprol 2024; 90:569-574. [PMID: 38595011 DOI: 10.25259/ijdvl_124_2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 09/15/2023] [Indexed: 04/11/2024]
Abstract
Objective To determine the diagnostic utility of C4d immunohistochemical marker in cases of bullous pemphigoid by calculating the sensitivity, specificity, positive predictive value and negative predictive value. Methods We conducted an exploratory study (retrospectively and prospectively) from January 2017 to June 2022. All direct immunofluorescence proven cases of bullous pemphigoid were included in the study while cases with inadequate tissue for immunohistochemistry studies were excluded. Results Among the 57 cases of bullous pemphigoid, 49 showed positivity for C4d marker. All the ten control cases of inflammatory dermatoses were negative for C4d staining. A sensitivity of 86%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 55.56% were calculated with a confidence interval of 95%. Limitation It is a single centre study. Selection bias may come into play. Conclusion Direct immunofluorescence on fresh or frozen skin tissue remains the gold standard. But in circumstances where direct immunofluorescence facilities are not available, C4d immunohistochemistry marker staining on formalin-fixed paraffin-embedded material submitted for standard microscopic investigation can, in most cases, confirm the diagnosis of bullous pemphigoid, obviating the need for a second biopsy.
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Affiliation(s)
- Raaga Sneha Muppala
- Department of Pathology, Jagadguru Sri Shivarathreeshwara Medical College, JSS Academy of Higher Education and Research, Mysuru, India
| | - Vijaya Basavaraj
- Department of Pathology, Jagadguru Sri Shivarathreeshwara Medical College, JSS Academy of Higher Education and Research, Mysuru, India
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2
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Vikár S, Szilveszter KP, Koszorú K, Sárdy M, Mócsai A. The Syk Inhibitor Entospletinib Abolishes Dermal-Epidermal Separation in a Fully Human Ex Vivo Model of Bullous Pemphigoid. J Invest Dermatol 2024; 144:1733-1742. [PMID: 38296021 DOI: 10.1016/j.jid.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/18/2023] [Accepted: 01/10/2024] [Indexed: 03/06/2024]
Abstract
Bullous pemphigoid (BP) is an autoantibody-mediated blistering skin disease characterized by local inflammation and dermal-epidermal separation, with no approved targeted therapy. The Syk tyrosine kinase is critical for various functions of the immune response. Second-generation Syk inhibitors such as entospletinib are currently being tested for hematological malignancies. Our aim was to test the effect of entospletinib in a fully human model system of BP. Incubating BP serum-treated human frozen skin sections with normal human granulocytes and fresh plasma triggered dermal-epidermal separation that was dependent on complement, NADPH oxidase, and protease activity. Entospletinib dramatically reduced dermal-epidermal separation with a half-maximal inhibitory concentration of ≈16 nM. Entospletinib also reduced ROS production, granule release, and spreading of human granulocytes plated on immobilized immune complexes consisting either of a generic antigen-antibody pair or of recombinant collagen type XVII (BPAg2) and BP serum components (supposedly autoantibodies). However, entospletinib did not affect the chemotactic migration of human granulocytes or their responses to nonphysiological stimulation by phorbol esters. Entospletinib had no effect on the survival of granulocytes either. Taken together, entospletinib abrogates dermal-epidermal separation, likely through inhibition of granulocyte responsiveness to deposited immune complexes. Entospletinib or other Syk inhibitors may provide therapeutic benefits in BP.
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Affiliation(s)
- Simon Vikár
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Kata P Szilveszter
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Kamilla Koszorú
- Department of Dermatology, Venereology and Dermatooncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Miklós Sárdy
- Department of Dermatology, Venereology and Dermatooncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Attila Mócsai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary; HUN-REN-SU Inflammation Physiology Research Group, Hungarian Research Network, Semmelweis University, Budapest, Hungary.
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3
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Im D, Ueda K, Niwa H, Tanaka K, Iwata H. Low pH condition impairs BP-IgG binding to the basement membrane zone. J Dermatol 2024; 51:643-648. [PMID: 38482975 DOI: 10.1111/1346-8138.17175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 05/03/2024]
Abstract
Bullous pemphigoid (BP), an autoimmune subepidermal blistering disease, shows tense blisters associated with urticarial erythema. Tissue-bound Immunoglobulin G (IgG) at the basement membrane zone (BMZ) detected by direct immunofluorescence (DIF) is strong evidence for a diagnosis of BP. The sensitivity of DIF is higher in complement component 3 (C3) than in IgG, but the reason for this different sensitivity is not fully understood. In this study, we performed several ex vivo studies to investigate the possible mechanism of IgG negativity and C3 positivity at the BMZ by DIF in some BP cases. First, sera from BP patients showing IgG negativity by DIF were found to clearly react to the BMZ in their own DIF skin samples. Next, indirect immunofluorescence (IIF) was performed using sera diluted with different pH phosphate-buffered saline (PBS), pH 7.4, 6.0, and 3.0. Patients' sera diluted with pH 7.4 PBS showed linear staining at the BMZ, but sera diluted with pH 6.0 PBS and pH 3.0 PBS showed lower fluorescence intensities. Finally, sections of skin from BP patients were pre-incubated with different pH PBS (pH 3.0, 6.0, and 7.4), followed by staining with anti-human IgG and C3. The fluorescence intensities were notably lower for IgG and C3 that had been pre-incubated with pH 3.0 PBS and pH 6.0 PBS than for IgG and C3 that had been pre-incubated with pH 7.4 PBS. These results suggest that a low pH condition hinders the binding of autoantibodies to the BMZ, that is, the drop in tissue pH induced by inflammation inhibits autoantibodies from depositing at the BMZ. Furthermore, the drop in tissue pH causes tissue-bound autoantibodies to detach from the BMZ. Complement fragments are activated not only on IgG but also on the cell surface of cells close to IgG during complement activation. IgG may detach from the BMZ under low pH condition induced by inflammation, but some complement fragments remain at the BMZ. These phenomena may help to explain why C3 is more sensitive than IgG when DIF is used to diagnose BP.
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Affiliation(s)
- Dongjun Im
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Keisuke Ueda
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Hirofumi Niwa
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Kayoko Tanaka
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Hiroaki Iwata
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
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4
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Karakioulaki M, Eyerich K, Patsatsi A. Advancements in Bullous Pemphigoid Treatment: A Comprehensive Pipeline Update. Am J Clin Dermatol 2024; 25:195-212. [PMID: 38157140 PMCID: PMC10866767 DOI: 10.1007/s40257-023-00832-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2023] [Indexed: 01/03/2024]
Abstract
ABASTRACT Bullous pemphigoid (BP) is a common autoimmune bullous disease affecting mainly the elderly, with rising incidence due to increased life expectancy. This disease is characterized by tense bullous lesions on normal or erythematous skin, accompanied by pruritus. BP pathogenesis involves autoantibodies against hemidesmosomal proteins BP180 and BP230, leading to detachment at the dermo-epidermal junction as well as blister formation. BP is associated with coexisting comorbidities and drug exposure, and its management often requires high doses or chronic use of systemic glucocorticoids, posing risks of adverse effects. This review focuses on novel treatment options for BP, exploring therapies targeting different immune pathways. Rituximab, a CD20 monoclonal antibody, depletes B-lymphocytes and has shown efficacy in severe cases. Dupilumab, targeting interleukin (IL)-4 receptor α and thus blocking IL-4 and IL-13, downregulates type 2 helper (Th2) responses and has demonstrated promising results. Targeting eosinophil-related molecules using bertilimumab and AKST4290 has yielded positive results in clinical trials. Omalizumab, an immunoglobulin (Ig) E antibody, can reduce disease severity and allows corticosteroid tapering in a number of cases. Complement inhibitors such as nomacopan and avdoralimab are being investigated. IL-17 and IL-23 inhibitors such as secukinumab and tildrakizumab have shown potential in a limited number of case reports. Neonatal Fc receptor antagonists such as efgartigimod are under investigation. Additionally, topical therapies and Janus kinase inhibitors are being explored as potential treatments for BP. These novel therapies offer promising alternatives for managing BP, with potential to improve outcomes and reduce high cumulative doses of systemic corticosteroids and related toxicities. Further research, including controlled clinical trials, is needed to establish their efficacy, safety, and optimal dosing regimens for BP management.
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Affiliation(s)
- Meropi Karakioulaki
- Department of Dermatology and Venerology, Medical Center, University Hospital Freiburg, Freiburg, Germany
| | - Kilian Eyerich
- Department of Dermatology and Venerology, Medical Center, University Hospital Freiburg, Freiburg, Germany
| | - Aikaterini Patsatsi
- Second Department of Dermatology, School of Medicine, Papageorgiou Hospital, Aristotle University, Thessaloníki, Greece.
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5
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Tsuji H, Ichiki N, Niwa H, Iwata H. Bullous pemphigoid following hand, foot, and mouth disease. J Dermatol 2024; 51:e68-e69. [PMID: 37804056 DOI: 10.1111/1346-8138.16979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 10/08/2023]
Affiliation(s)
- Hiromu Tsuji
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Naohisa Ichiki
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Hirofumi Niwa
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Hiroaki Iwata
- Department of Dermatology, Gifu University Graduate School of Medicine, Gifu, Japan
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Pigors M, Patzelt S, Reichhelm N, Dworschak J, Khil'chenko S, Emtenani S, Bieber K, Hofrichter M, Kamaguchi M, Goletz S, Köhl G, Köhl J, Komorowski L, Probst C, Vanderheyden K, Balbino B, Ludwig RJ, Verheesen P, Schmidt E. Bullous pemphigoid induced by IgG targeting type XVII collagen non-NC16A/NC15A extracellular domains is driven by Fc gamma receptor- and complement-mediated effector mechanisms and is ameliorated by neonatal Fc receptor blockade. J Pathol 2024; 262:161-174. [PMID: 37929639 DOI: 10.1002/path.6220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/18/2023] [Accepted: 09/21/2023] [Indexed: 11/07/2023]
Abstract
Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by autoantibodies targeting type XVII collagen (Col17) with the noncollagenous 16A (NC16A) ectodomain representing the immunodominant site. The role of additional extracellular targets of Col17 outside NC16A has not been unequivocally demonstrated. In this study, we showed that Col17 ectodomain-reactive patient sera depleted in NC16A IgG induced dermal-epidermal separation in a cryosection model indicating the pathogenic potential of anti-Col17 non-NC16A extracellular IgG. Moreover, injection of IgG targeting the murine Col17 NC14-1 domains (downstream of NC15A, the murine homologue of human NC16A) into C57BL/6J mice resulted in erythematous skin lesions and erosions. Clinical findings were accompanied by IgG/C3 deposits along the basement membrane and subepidermal blistering with inflammatory infiltrates. Disease development was significantly reduced in either Fc-gamma receptor (FcγR)- or complement-5a receptor-1 (C5aR1)-deficient mice. Inhibition of the neonatal FcR (FcRn), an atypical FcγR regulating IgG homeostasis, with the murine Fc fragment IgG2c-ABDEG, a derivative of efgartigimod, reduced anti-NC14-1 IgG levels, resulting in ameliorated skin inflammation compared with isotype-treated controls. These data demonstrate that the pathogenic effects of IgG targeting the Col17 domain outside human NC16A/murine NC15A are partly attributable to antibody-mediated FcγR- and C5aR1 effector mechanisms while pharmacological inhibition of the FcRn represents a promising treatment for BP. The mouse model of BP will be instrumental in further investigating the role of Col17 non-NC16A/NC15A extracellular epitopes and validating new therapies for this disease. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Manuela Pigors
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Sabrina Patzelt
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Niklas Reichhelm
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Jenny Dworschak
- Institute of Experimental Immunology, EUROIMMUN AG, Lübeck, Germany
| | | | - Shirin Emtenani
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Katja Bieber
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Maxi Hofrichter
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Mayumi Kamaguchi
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Stephanie Goletz
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
| | - Gabriele Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lars Komorowski
- Institute of Experimental Immunology, EUROIMMUN AG, Lübeck, Germany
| | - Christian Probst
- Institute of Experimental Immunology, EUROIMMUN AG, Lübeck, Germany
| | | | | | - Ralf J Ludwig
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University of Lübeck, Lübeck, Germany
| | | | - Enno Schmidt
- Lübeck Institute of Experimental Dermatology, University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University of Lübeck, Lübeck, Germany
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7
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Zhang Y, Dang J, Li R, Chen X, Zhu X, Wang M. Clinical Features of Paediatric Inflammatory Epidermolysis Bullosa Acquisita: A Case Series Study. Acta Derm Venereol 2024; 104:adv11917. [PMID: 38270257 PMCID: PMC10831865 DOI: 10.2340/actadv.v104.11917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 11/08/2023] [Indexed: 01/26/2024] Open
Abstract
Epidermolysis bullosa acquisita (EBA) rarely develops in childhood. This study retrospectively recruited paediatric patients with EBA (age ≤ 16 years), diagnosed by clinical and histopathological features and results of immunofluorescence, immunoblotting and enzyme-linked immunosorbent assay (ELISA), and reviews their clinical manifestations, histopathology, immunological features, and responses to various treatments. All 7 included patients presented with inflammatory EBA. Among them, 3 had a bullous pemphigoid-like phenotype. Pathologically, in addition to dermal-epidermal blistering, in all patients, the distribution of neutrophils was superficial perivascular or interstitial, or in the dermal papilla. Mixed neutrophils and eosinophils were detected in 2 of the 3 patients with bullous pemphigoid-like phenotypes. In addition to treatment with glucocorticoids, dapsone was administered in 4 patients, while thalidomide and sulfasalazine were administered in 1 patient. All patients responded to the these therapies. Relapse was mainly due to reduction and cessation of glucocorticoids. In conclusion, EBA in childhood may be unique, and thus distinct from its adult counterpart. Specific treatment and follow-up protocols are required for therapy of this rare autoimmune skin disease in children.
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Affiliation(s)
- Yuexin Zhang
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Jingyang Dang
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Ruoyu Li
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Xixue Chen
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Xuejun Zhu
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China
| | - Mingyue Wang
- Department of Dermatology, Peking University First Hospital, Beijing, China; National Clinical Research Center for Skin and Immune Diseases, Beijing, China; Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Beijing, China.
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8
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Toh WH, Lee HE, Chen CB. Targeting type 2 inflammation in bullous pemphigoid: current and emerging therapeutic approaches. Front Med (Lausanne) 2023; 10:1196946. [PMID: 37614956 PMCID: PMC10442825 DOI: 10.3389/fmed.2023.1196946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 07/19/2023] [Indexed: 08/25/2023] Open
Abstract
Bullous pemphigoid (BP) is one of the most common autoimmune bullous diseases and mainly affects an elderly population with multi-morbidity. Due to the frailty of many BP patients, existing treatment options are limited. The blisters associated with BP result from IgG and IgE autoantibodies binding to the central components of hemidesmosome, BP180, and BP230, stimulating a destructive inflammatory process. The known characteristic features of BP, such as intense pruritus, urticarial prodrome, peripheral eosinophilia, elevated IgE, as well as recent expanding evidence from in vitro and in vivo studies implicate type 2 inflammation as an important driver of BP pathogenesis. Type 2 inflammation is an inflammatory pathway involving a subset of CD4+ T cells that secrete IL-4, IL-5, and IL-13, IgE-secreting B cells, and granulocytes, such as eosinophils, mast cells, and basophils. It is believed that effectors in type 2 inflammation may serve as novel and effective treatment targets for BP. This review focuses on recent understandings of BP pathogenesis with a particular emphasis on the role of type 2 inflammation. We summarize current clinical evidence of using rituximab (B-cell depletion), omalizumab (anti-IgE antibody), and dupilumab (anti-IL-4/13 antibody) in the treatment of BP. The latest advances in emerging targeted therapeutic approaches for BP treatment are also discussed.
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Affiliation(s)
- Wu Han Toh
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, United States
- Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, United States
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States
- Cancer Vaccine and Immune Cell Therapy Core Laboratory, Chang Gung Memorial Hospital, Chang Gung Immunology Consortium, Taoyuan, Taiwan
| | - Hua-En Lee
- Cancer Vaccine and Immune Cell Therapy Core Laboratory, Chang Gung Memorial Hospital, Chang Gung Immunology Consortium, Taoyuan, Taiwan
- Department of Dermatology and Drug Hypersensitivity Clinical and Research Center, Chang Gung Memorial Hospital, Taipei, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Chang Gung Immunology Consortium, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Bing Chen
- Cancer Vaccine and Immune Cell Therapy Core Laboratory, Chang Gung Memorial Hospital, Chang Gung Immunology Consortium, Taoyuan, Taiwan
- Department of Dermatology and Drug Hypersensitivity Clinical and Research Center, Chang Gung Memorial Hospital, Taipei, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Chang Gung Immunology Consortium, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan
- Department of Dermatology, Xiamen Chang Gung Hospital, Xiamen, China
- Xiamen Chang Gung Allergology Consortium, Xiamen Chang Gung Hospital, Xiamen, China
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9
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Seiler DL, Kähler KH, Kleingarn M, Sadik CD, Bieber K, Köhl J, Ludwig RJ, Karsten CM. The complement receptor C5aR2 regulates neutrophil activation and function contributing to neutrophil-driven epidermolysis bullosa acquisita. Front Immunol 2023; 14:1197709. [PMID: 37275893 PMCID: PMC10235453 DOI: 10.3389/fimmu.2023.1197709] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction The function of the second receptor for the complement cleavage product C5a, C5aR2, is poorly understood and often neglected in the immunological context. Using mice with a global deficiency of C5aR2, we have previously reported an important role of this receptor in the pathogenesis of the neutrophil-driven autoimmune disease epidermolysis bullosa acquisita (EBA). Based on in vitro analyses, we hypothesized that the absence of C5aR2 specifically on neutrophils is the cause of the observed differences. Here, we report the generation of a new mouse line with a LysM-specific deficiency of C5aR2. Methods LysM-specific deletion of C5aR2 was achieved by crossing LysMcre mice with tdTomato-C5ar2fl/fl mice in which the tdTomato-C5ar2 gene is flanked by loxP sites. Passive EBA was induced by subcutaneous injection of rabbit anti-mouse collagen type VII IgG. The effects of targeted deletion of C5ar2 on C5a-induced effector functions of neutrophils were examined in in vitro assays. Results We confirm the successful deletion of C5aR2 at both the genetic and protein levels in neutrophils. The mice appeared healthy and the expression of C5aR1 in bone marrow and blood neutrophils was not negatively affected by LysM-specific deletion of C5aR2. Using the antibody transfer mouse model of EBA, we found that the absence of C5aR2 in LysM-positive cells resulted in an overall amelioration of disease progression, similar to what we had previously found in mice with global deficiency of C5aR2. Neutrophils lacking C5aR2 showed decreased activation after C5a stimulation and increased expression of the inhibitory Fcγ receptor FcγRIIb. Discussion Overall, with the data presented here, we confirm and extend our previous findings and show that C5aR2 in neutrophils regulates their activation and function in response to C5a by potentially affecting the expression of Fcγ receptors and CD11b. Thus, C5aR2 regulates the finely tuned interaction network between immune complexes, Fcγ receptors, CD11b, and C5aR1 that is important for neutrophil recruitment and sustained activation. This underscores the importance of C5aR2 in the pathogenesis of neutrophil-mediated autoimmune diseases.
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Affiliation(s)
- Daniel L. Seiler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Katja H. Kähler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Marie Kleingarn
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Christian D. Sadik
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Katja Bieber
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Centre, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Ralf J. Ludwig
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
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10
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Ghosh M, Rana S. The anaphylatoxin C5a: Structure, function, signaling, physiology, disease, and therapeutics. Int Immunopharmacol 2023; 118:110081. [PMID: 36989901 DOI: 10.1016/j.intimp.2023.110081] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
The complement system is one of the oldest known tightly regulated host defense systems evolved for efficiently functioning cell-based immune systems and antibodies. Essentially, the complement system acts as a pivot between the innate and adaptive arms of the immune system. The complement system collectively represents a cocktail of ∼50 cell-bound/soluble glycoproteins directly involved in controlling infection and inflammation. Activation of the complement cascade generates complement fragments like C3a, C4a, and C5a as anaphylatoxins. C5a is the most potent proinflammatory anaphylatoxin, which is involved in inflammatory signaling in a myriad of tissues. This review provides a comprehensive overview of human C5a in the context of its structure and signaling under several pathophysiological conditions, including the current and future therapeutic applications targeting C5a.
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Affiliation(s)
- Manaswini Ghosh
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India.
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11
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Maglie R, Solimani F, Didona D, Pipitò C, Antiga E, Di Zenzo G. The cytokine milieu of bullous pemphigoid: Current and novel therapeutic targets. Front Med (Lausanne) 2023; 10:1128154. [PMID: 36814775 PMCID: PMC9939461 DOI: 10.3389/fmed.2023.1128154] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/23/2023] [Indexed: 02/09/2023] Open
Abstract
Bullous pemphigoid (BP) is the most common autoimmune bullous disease, characterized by severe pruritus and skin blistering. The loss of tolerance against Collagen XVII, also referred to as BP180, is the main pathogenic event of BP, leading to production of IgG autoantibodies which mainly target the juxtamembranous extracellular non-collagenous 16th A (NC16A) domain of BP180. A complex inflammatory network is activated upon autoantibody binding to the basement membrane zone; this inflammatory loop involves the complement cascade and the release of several inflammatory cytokines, chemokines and proteases from keratinocytes, lymphocytes, mast cells and granulocytes. Collectively, these events disrupt the integrity of the dermal-epidermal junction, leading to subepidermal blistering. Recent advances have led to identify novel therapeutic targets for BP, whose management is mainly based on the long-term use of topical and systemic corticosteroids. As an example, targeting type-2 T-helper cell-associated cytokines, such as Interleukin-4 and interleukin-13 has shown meaningful clinical efficacy in case series and studies; targeting IL-17 and IL-23 has also been tried, owing to an important role of these cytokines in the chronic maintenance phase of BP. In this review article, we discuss the complex cytokine milieu that characterized BP inflammation, highlighting molecules, which are currently investigated as present and future therapeutic targets for this life-threatening disease.
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Affiliation(s)
- Roberto Maglie
- Section of Dermatology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Farzan Solimani
- Department of Dermatology, Venereology and Allergology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany,BIH Charité Clinician Scientist Program, Berlin Institute of Health at Charité – Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, Berlin, Germany
| | - Dario Didona
- Department of Dermatology and Allergology, Philipps University, Marburg, Germany
| | - Carlo Pipitò
- Section of Dermatology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Emiliano Antiga
- Section of Dermatology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Giovanni Di Zenzo
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell’Immacolata (IDI)-IRCCS, Rome, Italy,*Correspondence: Giovanni Di Zenzo,
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12
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Ujiie H. What's new in the pathogeneses and triggering factors of bullous pemphigoid. J Dermatol 2023; 50:140-149. [PMID: 36412277 PMCID: PMC10098684 DOI: 10.1111/1346-8138.16654] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/21/2022] [Indexed: 11/23/2022]
Abstract
Bullous pemphigoid (BP) is a subepidermal blistering disease induced by autoantibodies to type XVII collagen (COL17, also called BP180) and BP230. Previous studies using patients' samples and animal disease models elucidated the complement-dependent and complement-independent pathways of blister formation, the pathogenic roles of immune cells (T and B cells, macrophages, mast cells, neutrophils, eosinophils), and the pathogenicity of IgE autoantibodies in BP. This review introduces the recent progress on the mechanism behind the epitope-spreading phenomenon in BP, which is considered to be important to understand the chronic and intractable disease course of BP, and the pathogenicity of anti-BP230 autoantibodies, mainly focusing on studies that used active disease models. To clarify the pathogenesis of BP, the mechanism behind the breakdown of immune tolerance to BP antigens should be investigated. Recent studies using various experimental models have revealed important roles for regulatory T cells in the maintenance of self-tolerance to COL17 and BP230 as well as in the suppression of inflammation triggered by the binding of antibodies to COL17. Notably, physical stresses such as trauma, thermal burns, bone fractures, irradiation and ultraviolet exposure, some pathologic conditions such as neurological diseases and hematological malignancies, and the use of dipeptidyl peptidase-IV inhibitors and immune checkpoint inhibitors have been reported as triggering factors for BP. These factors and certain underlying conditions such as genetic background, regulatory T-cell dysfunction or aging might synergistically affect some individuals and eventually induce BP. Further studies on the breakdown of self-tolerance and on the identification of key molecules that are relevant to blister formation and inflammation may expand our understanding of BP's etiology and may lead to the development of novel therapeutic approaches.
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Affiliation(s)
- Hideyuki Ujiie
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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13
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Giang J, van Doorn MBA, Diercks GFH, de Cordoba SR, van den Bosch TPP, Schreurs MWJ, Poppelaars F, Damman J. Successful pharmacological intervention at different levels of the complement system in an in vitro complement fixation model for bullous pemphigoid. Exp Dermatol 2023; 32:632-640. [PMID: 36704908 DOI: 10.1111/exd.14755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/12/2022] [Accepted: 01/10/2023] [Indexed: 01/28/2023]
Abstract
Bullous pemphigoid (BP) is characterized by deposition of immunoglobulins and complement along the epidermal basement membrane (BM). In humans, there is a lack of functional studies targeting the complement system (CS). This study investigates activation of all complement pathways in BP skin biopsies. Moreover, pharmacological inhibition at different levels of the CS was investigated using anti-complement compounds in a complement fixation BP assay. In this retrospective study, 21 frozen biopsies from BP patients were stained by direct immunofluorescence for C1q, MBL, ficolin-2, C4d, properdin, C3c and C5b-9. Sera from 10 patients were analysed in a complement fixation assay in the presence of C1 inhibitor, anti-factor B monoclonal antibody (mAb), anti-C3 mAb and anti-C5 mAb and compared with dexamethasone. The two readouts were the quantity of complement deposited along the BM and the release of sC5b-9 in the supernatant. Our results show classical and alternative complement pathway activation in BP skin biopsies, but could not demonstrate significant lectin pathway activation. In contrast to dexamethasone, complement deposition along the BM could be selectively inhibited by anti-C1 and anti- factor B. More downstream, selective intervention at the level of C3 and C5 could effectively reduce complement deposition along the BM and the release of sC5b-9 in the supernatant. This study shows that selective intervention in either the classical, alternative or terminal pathway prevented deposition of complement along the BM in an in vitro BP model. The results of our study greatly encourage the clinical development of complement inhibitors for the treatment of BP.
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Affiliation(s)
- Jenny Giang
- Department of Pathology, Maasstad Hospital, Rotterdam, The Netherlands
| | - Martijn B A van Doorn
- Department of Dermatology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.,Centre for Human Drug Research, Leiden, The Netherlands
| | - Gilles F H Diercks
- Department of Pathology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Santiago Rodriguez de Cordoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | | | - Marco W J Schreurs
- Department of Immunology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Felix Poppelaars
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jeffrey Damman
- Department of Pathology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands
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