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Mehta RS, Ali H, Dai Y, Yao B, Overman B, Ratanatharathorn V, Gill S, Socié G, Anderson K, Cahn JY, Mujeebuddin A, Champlin R, Shpall E, Holtan SG, Alousi A. A prospective phase 2 clinical trial of a C5a complement inhibitor for acute GVHD with lower GI tract involvement. Bone Marrow Transplant 2023; 58:991-999. [PMID: 37202544 PMCID: PMC10195122 DOI: 10.1038/s41409-023-01996-4] [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: 04/01/2022] [Revised: 03/29/2023] [Accepted: 04/19/2023] [Indexed: 05/20/2023]
Abstract
Involvement of lower gastrointestinal tract (LGI) occurs in 60% of patients with graft-versus-host-disease (GVHD). Complement components C3 and C5 are involved in GVHD pathogenesis. In this phase 2a study, we evaluated the safety and efficacy of ALXN1007, a monoclonal antibody against C5a, in patients with newly diagnosed LGI acute GVHD receiving concomitant corticosteroid. Twenty-five patients were enrolled; one was excluded from the efficacy analysis based upon negative biopsy. Most patients (16/25, 64%) had acute leukemia; 52% (13/25) had an HLA-matched unrelated donor; and 68% (17/25) received myeloablative conditioning. Half the patients (12/24) had a high biomarker profile, Ann Arbor score 3; 42% (10/24) had high-risk GVHD per Minnesota classification. Day-28 overall response was 58% (13/24 complete response, 1/24 partial response), and 63% by Day-56 (all complete responses). Day-28 overall response was 50% (5/10) in Minnesota high-risk and 42% (5/12) in high-risk Ann Arbor patients, increasing to 58% (7/12) by Day-56. Non-relapse mortality at 6-months was 24% (95% CI 11-53). The most common treatment-related adverse event was infection (6/25, 24%). Neither baseline complement levels (except for C5), activity, nor inhibition of C5a with ALXN1007 correlated with GVHD severity or responses. Further studies are needed to evaluate the role of complement inhibition in GVHD treatment.
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Affiliation(s)
- Rohtesh S Mehta
- Clinical Research Division Fred Hutch, University of Washington School of Medicine, Seattle, Washington, USA
| | | | - Yang Dai
- Alexion, AstraZeneca Rare Disease, New Haven, CT, USA
| | - Bert Yao
- Alexion, AstraZeneca Rare Disease, New Haven, CT, USA
| | - Bethany Overman
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Saar Gill
- Division of Hematology-Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gerard Socié
- University Paris VII Head of Hematology Transplantation APHP Hospital Saint Louis, Paris, France
| | | | | | | | - Richard Champlin
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Elizabeth Shpall
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Amin Alousi
- Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Wang Y, Huang L, Huang T, Geng S, Chen X, Huang X, Lai P, Du X, Weng J. The Gut Bacteria Dysbiosis Contributes to Chronic Graft-Versus-Host Disease Associated With a Treg/Th1 Ratio Imbalance. Front Microbiol 2022; 13:813576. [PMID: 36160244 PMCID: PMC9493085 DOI: 10.3389/fmicb.2022.813576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Dysbiosis of gut bacteria has been discovered in a large number of autoimmune diseases. However, the influence of the gut bacteria in the mice model of chronic sclerodermatous graft-versus-host disease (Scl-GVHD), a disease that resembles an autoimmune disease characterized by chronic inflammation of multiple organs, such as skin, remains elusive. Here, we explore the role of gut bacteria in an Scl-cGVHD mice model. Methods We established a mouse model of Scl-cGVHD, collected fecal flora, analyzed the composition, and diversity of intestinal flora using 16S rDNA amplicon sequencing, and detected the proportion of Treg and Th1 cells in splenocytes of Scl-cGVHD mice. To verify the immunoregulatory effect of Scl-cGVHD intestinal flora, we prepared bacterial extracts, co-cultured with splenocytes in vitro, and used flow cytometry to detect T cell differentiation and cytokine secretion. Results By examining T-cell differentiation in splenocytes of cGVHD mice, we found that Treg cells were significantly reduced (15.27 ± 0.23 vs. 12.23 ± 0.47, p = 0.0045) and Th1 cells were increased (1.54 ± 0.18 vs. 6.68 ± 0.80, p = 0.0034) in cGVHD mice. Significant differences were observed in the composition and diversity of the gut bacteria in mice with Scl-cGVHD versus without GVHD. Analysis of mice fecal bacteria samples (n = 10, 5 Scl-cGVHD and 5 Non-GVHD) showed significant separation [R = 0.732, p = 0.015, non-parametric analysis (ANOSIM)] in Scl-cGVHD and non-GVHD mice. The abundance of the family and genus Ruminococcaceae bacteria decreased and the family Lachnospiraceae and limited to the species Lachnospiraceae_bacterium_DW17 increased in Scl-cGVHD mice. In vitro results of the cellular level study suggest that the bacteria extracts of gut microbiota from Scl-cGVHD mice modulated the splenic T cells toward differentiation into CD4+IFN-γ+ Th1 cells (14.37 ± 0.32 vs. 10.40 ± 2.19, p = 0.036), and the percentage of CD4+CD25+Foxp3+ Tregs decreased (6.36 ± 0.39 vs. 8.66 ± 0.07, p = 0.001) compared with the non-GVHD mice. In addition, the secretion of proinflammatory interferon- γ (IFN-γ) cytokine in the supplement of cellular culture was increased (4,898.58 ± 235.82 vs. 4,347.87 ± 220.02 pg/ml, p = 0.042) in the mice model of the Scl-cGVHD group, but anti-inflammatory interleukin (IL)-10 decreased (7,636.57 ± 608.05 vs. 9,563.56 ± 603.34 pg/ml, p = 0.018). Conclusion Our data showed the different composition and diversity of gut bacteria in the Scl-cGVHD mice. The dysbiosis of gut bacteria may regulate the differentiation ratio of Treg and Th1 cells, which was associated with Scl-cGVHD.
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Gu G, Yang JZ, Zhang JQ, Sun LX. Regulatory T cells in allogeneic hematopoietic stem cell transplantation: From the lab to the clinic. Cell Immunol 2019; 346:103991. [PMID: 31607390 DOI: 10.1016/j.cellimm.2019.103991] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022]
Abstract
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curable strategy for the treatment of hematological malignancies and nonmalignant diseases. However, graft-versus-host disease (GVHD) and relapse are still two major causes of morbidity and mortality after allo-HSCT, and both restrict the improvement of transplant outcomes. Regulatory T cells (Tregs) has been successfully used in allo-SCT settings. In this review, we summarize recent advances in experimental studies that have evaluated the roles played by Tregs in the establishment of novel transplant modalities, the prevention of GVHD and the enhancement of immune reconstitution. We also discuss the application of Tregs in clinical to prevent acute GVHD, treat chronic GVHD, as well as enhance immune reconstitution and decrease leukemia relapse, all of which lead to improving transplant outcomes.
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Affiliation(s)
- Guang Gu
- Department of Rheumatology, Third Affiliated Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jian-Zhu Yang
- Department of Pathology, Third Affiliated Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jin-Qiao Zhang
- Department of Hematology, Third Affiliated Hospital of Hebei Medical University, Shijiazhuang, China
| | - Li-Xia Sun
- Department of Hematology, Third Affiliated Hospital of Hebei Medical University, Shijiazhuang, China.
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Chen XM, Weng JY, Lai PL, Wang YL, Huang X, Geng SX, Guo LY, Huang T, Zeng LJ, Du X. [Artesunate attenuate chronic graft-versus-host disease by regulating Th17/Treg balance]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2019; 40:63-68. [PMID: 30704231 PMCID: PMC7351699 DOI: 10.3760/cma.j.issn.0253-2727.2019.01.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
目的 探讨青蒿琥酯抗慢性移植物抗宿主病(cGVHD)的作用及可能机制。 方法 将B10D2小鼠的骨髓细胞和脾脏细胞混合悬液通过尾静脉输入近交系雌性BALB/c小鼠体内建立cGVHD模型,分别予青蒿琥酯(实验组)和丙酮腹腔(对照组)注射治疗。观察两组小鼠的cGVHD临床表现、生存时间和组织病理学改变;应用流式细胞术分析小鼠外周血和脾脏Th17和Treg细胞比例;免疫磁珠分选BALB/c小鼠脾脏CD4+T细胞,分别予丙酮和青蒿琥酯进行干预72 h,流式细胞术分析两组Th17/Treg细胞比例。 结果 ①实验组小鼠cGVHD临床症状较对照组明显减轻,生存时间延长[(55.71±6.99)d对(46.57±7.83)d,χ2=5.457,P=0.020]。②实验组小鼠皮肤及肺脏cGVHD病理损伤较轻。③与对照组比较,实验组小鼠外周血、脾脏Th17细胞比例均降低[(0.58±0.19)%对(1.51±0.18)%,t=7.233,P<0.001;(0.71±0.18)%对(1.48±0.38)%,t=3.653,P=0.011],Treg细胞比例增高[(8.40±0.23)%对(4.45±0.04)%,t=15.680,P<0.001;(10.48±0.48)%对(6.62±0.24)%,t=6.590,P=0.003],Th17/Treg细胞比值均下降(0.09±0.03对0.34±0.05,t=7.621,P=0.002;0.06±0.02对0.19±0.03,t=6.993,P=0.002)。④体外培养小鼠脾脏CD4+T细胞,青蒿琥酯干预组较对照组Th17细胞比例减低[(0.82±0.37)%对(3.39±1.22)%,t=4.044,P=0.007],Treg细胞比例明显增高[(34.63±1.29)%对(14.28±1.69)%,t=19.119,P<0.001],Th17/Treg细胞比值下降(0.24±0.09对0.02±0.01,t=4.780,P=0.003)。 结论 青蒿琥酯可通过减少Th17细胞及增加Treg细胞,恢复Th17/Treg平衡,减轻cGVHD的临床与病理学损伤,从而发挥抗cGVHD作用。
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Affiliation(s)
- X M Chen
- Department of Hematology, Guangdong General Hospital/Guangdong Academy of Medical Sciences, Guangdong Geriatrics Institute, Guangzhou 510080, China
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Kano M, Kobayashi T, Date M, Tennichi M, Hamaguchi Y, Strasser DS, Takehara K, Matsushita T. Attenuation of murine sclerodermatous models by the selective S1P 1 receptor modulator cenerimod. Sci Rep 2019; 9:658. [PMID: 30679645 PMCID: PMC6345830 DOI: 10.1038/s41598-018-37074-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/30/2018] [Indexed: 01/04/2023] Open
Abstract
Sphingosine-1-phosphate (S1P), a lipid mediator, regulates lymphocyte migration between lymphoid tissue and blood. Furthermore, S1P participates in several physiological phenomena including angiogenesis, inflammation, immune regulation, and neurotransmitter release. Moreover, S1P/S1P receptor signaling involves in systemic sclerosis (SSc) pathogenesis. This study aimed to investigate whether the selective S1P1 receptor modulator cenerimod attenuates murine sclerodermatous models. Cenerimod was orally administered to murine sclerodermatous chronic graft versus host disease (Scl-cGVHD) mice, either from day 0 to 42 or day 22 to 42 after bone marrow transplantation. Bleomycin-induced SSc model mice were administered cenerimod from day 0 to 28. Early cenerimod administration inhibited, and delayed cenerimod administration attenuated skin and lung fibrosis in Scl-cGVHD mice. Cenerimod suppressed the infiltration of CD4+ T cells, CD8+ T cells, and CD11b+ cells into the inflamed skin of Scl-cGVHD mice as opposed to control mice. In contrast, cenerimod increased the frequency of regulatory T cells in the spleen and skin of Scl-cGVHD mice. Additionally, cenerimod attenuated the mRNA expression of extracellular matrix and fibrogenic cytokines in the skin. Furthermore, cenerimod attenuated bleomycin-induced fibrosis in the skin and lung. Hence, the selective S1P1 receptor modulator cenerimod is a promising candidate for treating patients with SSc and Scl-cGVHD.
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Affiliation(s)
- Miyu Kano
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Tadahiro Kobayashi
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Mutsumi Date
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Momoko Tennichi
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Yasuhito Hamaguchi
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Daniel S Strasser
- Idorsia Pharmaceuticals Ltd., Drug Discovery, Hegenheimermattweg 91, CH-4123, Allschwil, Switzerland
| | - Kazuhiko Takehara
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan
| | - Takashi Matsushita
- Department of Dermatology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-8641, Japan.
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Khan MA, Shamma T. Complement factor and T-cell interactions during alloimmune inflammation in transplantation. J Leukoc Biol 2018; 105:681-694. [PMID: 30536904 DOI: 10.1002/jlb.5ru0718-288r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/25/2018] [Accepted: 11/21/2018] [Indexed: 02/06/2023] Open
Abstract
Complement factor and T-cell signaling during an effective alloimmune response plays a key role in transplant-associated injury, which leads to the progression of chronic rejection (CR). During an alloimmune response, activated complement factors (C3a and C5a) bind to their corresponding receptors (C3aR and C5aR) on a number of lymphocytes, including T-regulatory cells (Tregs), and these cell-molecular interactions have been vital to modulate an effective immune response to/from Th1-effector cell and Treg activities, which result in massive inflammation, microvascular impairments, and fibrotic remodeling. Involvement of the complement-mediated cell signaling during transplantation signifies a crucial role of complement components as a key therapeutic switch to regulate ongoing inflammatory state, and further to avoid the progression of CR of the transplanted organ. This review highlights the role of complement-T cell interactions, and how these interactions shunt the effector immune response during alloimmune inflammation in transplantation, which could be a novel therapeutic tool to protect a transplanted organ and avoid progression of CR.
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Affiliation(s)
- Mohammad Afzal Khan
- Organ Transplant Research Section, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Talal Shamma
- Organ Transplant Research Section, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
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Lai P, Chen X, Guo L, Wang Y, Liu X, Liu Y, Zhou T, Huang T, Geng S, Luo C, Huang X, Wu S, Ling W, Du X, He C, Weng J. A potent immunomodulatory role of exosomes derived from mesenchymal stromal cells in preventing cGVHD. J Hematol Oncol 2018; 11:135. [PMID: 30526632 PMCID: PMC6286548 DOI: 10.1186/s13045-018-0680-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/21/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Mesenchymal stromal cells (MSCs) are a promising therapy for preventing chronic Graft-Versus-Host Disease (cGVHD) due to their potent immunomodulatory properties. However, the safety concerns regarding the use of MSCs remain unsolved, and conflicting effects are observed due to the heterogeneity of MSCs. Recently, exosomes were shown to mediate the paracrine effects of MSCs, making it a potential candidate for cell-free therapies. The aim of this study is to investigate the efficacy and safety of MSCs-derived exosomes (MSCs-exo) in an established cGVHD mouse model. METHODS Bone marrow (BM)-derived MSCs were cultured, and the supernatants of these cultures were collected to prepare exosomes using ultracentrifugation. Exosomes from human dermal fibroblasts (Fib-exo) were used as a negative control. The cGVHD model was established, and tail vein injections of MSCs-exo or Fib-exo were administered once per week for 6 weeks. The symptoms and signs of cGVHD were monitored, and histopathological changes were detected by hematoxylin and eosin and Masson staining. The effects of MSCs-exo on Th17, Th1, and Treg were evaluated by flow cytometry, qPCR, and Luminex. In addition, human peripheral blood mononuclear cells (PBMCs) were stimulated and treated with MSCs-exo in vitro. IL-17-expressing Th17 and IL-10-expressing Treg were evaluated by flow cytometry, qPCR, and ELISA. RESULTS We found that MSCs-exo effectively prolonged the survival of cGVHD mice and diminished the clinical and pathological scores of cGVHD. Fibrosis in the skin, lung, and liver was significantly ameliorated by MSCs-exo application. In MSCs-exo treated mice, activation of CD4+ T cells and their infiltration into the lung were reduced. Of note, MSCs-exo exhibited potent immunomodulatory effects via the inhibition of IL-17-expressing pathogenic T cells and induction of IL-10-expressing regulatory cells during cGVHD. The expressions of Th17 cell-relevant transcription factors and pro-inflammatory cytokines was markedly reduced after MSCs-exo treatment. In vitro, MSCs-exo blocked Th17 differentiation and improved the Treg phenotype in PBMCs obtained from healthy donors and patients with active cGVHD, further indicating the regulatory effect of MSCs-exo on GVHD effector T cells. CONCLUSIONS Our data suggested that MSCs-exo could improve the survival and ameliorate the pathologic damage of cGVHD by suppressing Th17 cells and inducing Treg. This finding provides a novel alternative approach for the treatment of cGVHD.
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Affiliation(s)
- Peilong Lai
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China.,Guangdong Geriatrics Institute, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Xiaomei Chen
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Liyan Guo
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Yulian Wang
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Xialin Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, People's Republic of China
| | - Yan Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, People's Republic of China
| | - Tian Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, People's Republic of China
| | - Tian Huang
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Suxia Geng
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Chengwei Luo
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Xin Huang
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Suijing Wu
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Wei Ling
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China
| | - Xin Du
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China. .,Guangdong Geriatrics Institute, Guangzhou, Guangdong, 510080, People's Republic of China.
| | - Chang He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, People's Republic of China.
| | - Jianyu Weng
- Department of Hematology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, 510080, People's Republic of China. .,Guangdong Geriatrics Institute, Guangzhou, Guangdong, 510080, People's Republic of China.
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Khan MA, Alanazi F, Ahmed HA, Vater A, Assiri AM, Broering DC. C5a Blockade Increases Regulatory T Cell Numbers and Protects Against Microvascular Loss and Epithelial Damage in Mouse Airway Allografts. Front Immunol 2018; 9:1010. [PMID: 29881374 PMCID: PMC5976734 DOI: 10.3389/fimmu.2018.01010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/23/2018] [Indexed: 12/15/2022] Open
Abstract
Microvascular injury during acute rejection has been associated with massive infiltration of CD4+ T effector cells, and the formation of complement products (C3a and C5a). Regulatory T cells (Tregs) are potent immunosuppressors of the adaptive immune system and have proven sufficient to rescue microvascular impairments. Targeting C5a has been linked with improved microvascular recovery, but its effects on the Treg and T effector balance is less well known. Here, we demonstrate the impact of C5a blockade on Treg induction and microvascular restoration in rejecting mouse airway allografts. BALB/c→C57BL/6 allografts were treated with a C5a-neutralizing l-aptamer (10 mg/kg, i.p. at d0 and every second day thereafter), and allografts were serially monitored for Treg infiltration, tissue oxygenation (tpO2), microvascular blood flow, and functional microvasculature between donor and recipients during allograft rejection. We demonstrated that C5a blocking significantly leads to enhanced presence of Tregs in the allograft, reinstates donor-recipient functional microvasculature, improves tpO2, microvascular blood flow, and epithelial repair, followed by an upregulation of IL-5, TGF-β, IL-10 vascular endothelial growth factor, and ANGPT1 gene expression, while it maintained a healthy epithelium and prevented subepithelial collagen deposition at d28 posttransplantation. Together, these data indicate that inhibition of C5a signaling has potential to preserve microvasculature and rescue allograft from a sustained hypoxic/ischemic phase, limits airway tissue remodeling through the induction of Treg-mediated immune tolerance. These findings may be useful in designing anti-C5a therapy in combination with existing immunosuppressive regimens to rescue tissue/organ rejection.
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Affiliation(s)
- Mohammad Afzal Khan
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Fatimah Alanazi
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Hala Abdalrahman Ahmed
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | | | - Abdullah Mohammed Assiri
- Comparative Medicine Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- College of Medicine, AlFaisal University, Riyadh, Saudi Arabia
- Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Dieter Clemens Broering
- Organ Transplant Centre, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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