Maximilian Haist
Postdoctoral Scholar, Microbiology and Immunology
Bio
Dr. Haist is a clinician scientist who explores the tumor microenvironment of advanced skin cancer patients to identify predictive biomarkers and immunological signatures using single-cell multiplexing technologies. As a Ph.D. student, Dr. Haist investigated the role of tumor hypoxia and the adenosine system in patients with melanoma brain metastases treated with combined radiochemotherapy. Currently, Dr Haist is a Postdoctoral Fellow in Dr. Garry Nolan´s lab and comes with interest in multiplex technologies to analyze the organization of effective anti-tumor immune responses within the tumor microenvironment.
Honors & Awards
-
TRANSMED Jumpstart Fellowship, Else-Kröner Fresenius Foundation (2020)
-
Walter-Benjamin Fellowship, German Research Foundation (2022)
Professional Education
-
Staatsexamen, Johannes Gutenberg Universitat Mainz (2019)
-
Doctor of Medicine, Johannes Gutenberg Universitat Mainz (2021)
-
MD, Johannes-Gutenberg University Mainz, Germany and University of Zurich, Switzerland, Medicine (2019)
-
Dr. med., Department of Radiation Oncology and Radiotherapy, University Medical Center of the Johannes-Gutenberg University Mainz, Germany, Melanoma Immunotherapy (2021)
All Publications
-
T cell-mediated curation and restructuring of tumor tissue coordinates an effective immune response.
Cell reports
2023; 42 (12): 113494
Abstract
Antigen-specific T cells traffic to, are influenced by, and create unique cellular microenvironments. Here we characterize these microenvironments over time with multiplexed imaging in a melanoma model of adoptive T cell therapy and human patients with melanoma treated with checkpoint inhibitor therapy. Multicellular neighborhood analysis reveals dynamic immune cell infiltration and inflamed tumor cell neighborhoods associated with CD8+ T cells. T cell-focused analysis indicates T cells are found along a continuum of neighborhoods that reflect the progressive steps coordinating the anti-tumor immune response. More effective anti-tumor immune responses are characterized by inflamed tumor-T cell neighborhoods, flanked by dense immune infiltration neighborhoods. Conversely, ineffective T cell therapies express anti-inflammatory cytokines, resulting in regulatory neighborhoods, spatially disrupting productive T cell-immune and -tumor interactions. Our study provides in situ mechanistic insights into temporal tumor microenvironment changes, cell interactions critical for response, and spatial correlates of immunotherapy outcomes, informing cellular therapy evaluation and engineering.
View details for DOI 10.1016/j.celrep.2023.113494
View details for PubMedID 38085642
-
Treatment management for BRAF-mutant melanoma patients with tumor recurrence on adjuvant therapy: a multicenter study from the prospective skin cancer registry ADOREG.
Journal for immunotherapy of cancer
2023; 11 (9)
Abstract
Adjuvant therapy with immune-checkpoint inhibitors (CPI) or BRAF/MEK-directed targeted therapy (TT) improves recurrence-free survival (RFS) for patients with advanced, BRAFV600-mutant (BRAFmut) resected melanoma. However, 40% of these patients will develop distant metastases (DM) within 5 years, which require systemic therapy. Little data exist to guide the choice of upfront adjuvant therapy or treatment management upon DM. This study evaluated the efficacy of subsequent treatments following tumor recurrence upon upfront adjuvant therapy.For this multicenter cohort study, we identified 515 BRAFmut patients with resected stage III melanoma who were treated with PD-1 inhibitors (anti-PD1) or TT in the adjuvant setting. Disease characteristics, treatment regimens, details on tumor recurrence, subsequent treatment management, and survival outcomes were collected within the prospective, real-world skin cancer registry ADOReg. Primary endpoints included progression-free survival (PFS) following DM and best tumor response to first-line (1L) treatments.Among 515 eligible patients, 273 patients received adjuvant anti-PD1 and 242 adjuvant TT. At a median follow-up of 21 months, 54.6% of anti-PD1 patients and 36.4% of TT patients recurred, while 39.6% (anti-PD1) and 29.3% (TT) developed DM. Risk of recurrence was significantly reduced in patients treated with TT compared with anti-PD1 (adjusted HR 0.52; 95% CI 0.40 to 0.68, p<0.001). Likewise, median RFS was significantly longer in TT-treated patients (31 vs 17 months, p<0.001). Patients who received TT as second adjuvant treatment upon locoregional recurrence had a longer RFS2 as compared with adjuvant CPI (41 vs 6 months, p=0.009). Patients who recurred at distant sites following adjuvant TT showed favorable response rates (42.9%) after switching to 1L ipilimumab+nivolumab (ipi+nivo). Patients with DM during adjuvant anti-PD1 achieved response rates of 58.7% after switching to 1L TT and 35.3% for 1L ipi+nivo. Overall, median PFS was significantly longer in patients who switched treatments for stage IV disease (median PFS 9 vs 5 months, p=0.004).BRAFmut melanoma patients who developed DM upon upfront adjuvant therapy achieve favorable tumor control and prolonged PFS after switching treatment modalities in the first-line setting of stage IV disease. Patients with locoregional recurrence benefit from complete resection of recurrence followed by a second adjuvant treatment with TT.
View details for DOI 10.1136/jitc-2023-007630
View details for PubMedID 37730278
View details for PubMedCentralID PMC10510881
-
Response to primary chemoradiotherapy of locally advanced oropharyngeal carcinoma is determined by the degree of cytotoxic T cell infiltration within tumor cell aggregates.
Frontiers in immunology
2023; 14: 1070203
Abstract
Effective anti-tumor immune responses are mediated by T cells and require organized, spatially coordinated interactions within the tumor microenvironment (TME). Understanding coordinated T-cell-behavior and deciphering mechanisms of radiotherapy resistance mediated by tumor stem cells will advance risk stratification of oropharyngeal cancer (OPSCC) patients treated with primary chemoradiotherapy (RCTx).To determine the role of CD8 T cells (CTL) and tumor stem cells for response to RCTx, we employed multiplex immunofluorescence stains on pre-treatment biopsy specimens from 86 advanced OPSCC patients and correlated these quantitative data with clinical parameters. Multiplex stains were analyzed at the single-cell level using QuPath and spatial coordination of immune cells within the TME was explored using the R-package Spatstat.Our observations demonstrate that a strong CTL-infiltration into the epithelial tumor compartment (HR for overall survival, OS: 0.35; p<0.001) and the expression of PD-L1 on CTL (HR: 0.36; p<0.001) were both associated with a significantly better response and survival upon RCTx. As expected, p16 expression was a strong predictor of improved OS (HR: 0.38; p=0.002) and correlated with overall CTL infiltration (r: 0.358, p<0.001). By contrast, tumor cell proliferative activity, expression of the tumor stem cell marker CD271 and overall CTL infiltration, regardless of the affected compartment, were not associated with response or survival.In this study, we could demonstrate the clinical relevance of the spatial organization and the phenotype of CD8 T cells within the TME. In particular, we found that the infiltration of CD8 T cells specifically into the tumor cell compartment was an independent predictive marker for response to chemoradiotherapy, which was strongly associated with p16 expression. Meanwhile, tumor cell proliferation and the expression of stem cell markers showed no independent prognostic effect for patients with primary RCTx and thus requires further study.
View details for DOI 10.3389/fimmu.2023.1070203
View details for PubMedID 37187729
View details for PubMedCentralID PMC10175951
-
Neutrophil-Specific Knockdown of beta 2 Integrins Impairs Antifungal Effector Functions and Aggravates the Course of Invasive Pulmonal Aspergillosis
FRONTIERS IN IMMUNOLOGY
2022; 13: 823121
Abstract
β2-integrins are heterodimeric surface receptors that are expressed specifically by leukocytes and consist of a variable α (CD11a-d) and a common β-subunit (CD18). Functional impairment of CD18, which causes leukocyte adhesion deficiency type-1 results in an immunocompromised state characterized by severe infections, such as invasive pulmonary aspergillosis (IPA). The underlying immune defects have largely been attributed to an impaired migratory and phagocytic activity of polymorphonuclear granulocytes (PMN). However, the exact contribution of β2-integrins for PMN functions in-vivo has not been elucidated yet, since the mouse models available so far display a constitutive CD18 knockout (CD18-/- or CD18hypo). To determine the PMN-specific role of β2-integrins for innate effector functions and pathogen control, we generated a mouse line with a Ly6G-specific knockdown of the common β-subunit (CD18Ly6G cKO). We characterized CD18Ly6G cKO mice in-vitro to confirm the PMN-specific knockdown of β2-integrins. Next, we investigated the clinical course of IPA in A. fumigatus infected CD18Ly6G cKO mice with regard to the fungal burden, pulmonary inflammation and PMN response towards A. fumigatus. Our results revealed that the β2-integrin knockdown was restricted to PMN and that CD18Ly6G cKO mice showed an aggravated course of IPA. In accordance, we observed a higher fungal burden and lower levels of proinflammatory innate cytokines, such as TNF-α, in lungs of IPA-infected CD18Ly6G cKO mice. Bronchoalveolar lavage revealed higher levels of CXCL1, a stronger PMN-infiltration, but concomitantly elevated apoptosis of PMN in lungs of CD18Ly6G cKO mice. Ex-vivo analysis further unveiled a strong impairment of PMN effector function, as reflected by an attenuated phagocytic activity, and a diminished generation of reactive oxygen species (ROS) and neutrophil-extracellular traps (NET) in CD18-deficient PMN. Overall, our study demonstrates that β2-integrins are required specifically for PMN effector functions and contribute to the clearance of A. fumigatus by infiltrating PMN, and the establishment of an inflammatory microenvironment in infected lungs.
View details for DOI 10.3389/fimmu.2022.823121
View details for Web of Science ID 000813318000001
View details for PubMedID 35734179
View details for PubMedCentralID PMC9207500
-
Second opinion and self-efficacy in German skin cancer patients
JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT
2024
Abstract
The global incidence of skin cancer has steadily increased in recent years. Accordingly, patients require information on diagnosis and treatment options while dealing with the perceived impact of the diagnosis. In 2015, the German government enacted legislation under the Social Code (SGB V, § 27b), granting patients the right to obtain a second medical opinion.Utilizing a standardized questionnaire, our study aims to explore whether patients diagnosed with skin cancer actively pursue a second medical opinion and to evaluate any potential disruptions to their daily lives. We collected a total of 714 completed questionnaires.The majority of those seeking a second opinion were diagnosed with malignant melanoma (96, 58%). Primary motivations for seeking a second opinion included seeking reassurance regarding treatment decisions and obtaining further information. Additionally, seeking a second opinion was correlated with a significantly lower internal locus of control, indicating a belief that their actions are not solely determined by their own abilities. Notably, we observed a greater impairment of daily life among younger participants and those with advanced cancer.Overall, our study shows that second opinions often strengthened the patient-physician interaction and provided additional reassurance, especially in patients with a weak perception of control. Moreover, we found that the impairment of quality of life and both internal and external locus of control decrease significantly in advanced tumor stages. Hence, it is imperative to identify additional interventions aimed at bolstering internal resilience and locus of control, thereby enhancing patients' capacity to cope with their cancer diagnosis.
View details for DOI 10.1111/ddg.15512
View details for Web of Science ID 001310053100001
View details for PubMedID 39263772
-
The skin microbiome stratifies patients with cutaneous T cell lymphoma and determines event-free survival.
NPJ biofilms and microbiomes
2024; 10 (1): 74
Abstract
Mycosis fungoides (MF) is the most common entity of Cutaneous T cell lymphomas (CTCL) and is characterized by the presence of clonal malignant T cells in the skin. The role of the skin microbiome for MF development and progression are currently poorly understood. Using shotgun metagenomic profiling, real-time qPCR, and T cell receptor sequencing, we compared lesional and nonlesional skin of 20 MF patients with early and advanced MF. Additionally, we isolated Staphylococcus aureus and other bacteria from MF skin for functional profiling and to study the S. aureus virulence factor spa. We identified a subgroup of MF patients with substantial dysbiosis on MF lesions and concomitant outgrowth of S. aureus on plaque-staged lesions, while the other MF patients had a balanced microbiome on lesional skin. Dysbiosis and S. aureus outgrowth were accompanied by ectopic levels of cutaneous antimicrobial peptides (AMPs), including adaptation of the plaque-derived S. aureus strain. Furthermore, the plaque-derived S. aureus strain showed a reduced susceptibility towards antibiotics and an upregulation of the virulence factor spa, which may activate the NF-κB pathway. Remarkably, patients with dysbiosis on MF lesions had a restricted T cell receptor repertoire and significantly lower event-free survival. Our study highlights the potential for microbiome-modulating treatments targeting S. aureus to prevent MF progression.
View details for DOI 10.1038/s41522-024-00542-4
View details for PubMedID 39198450
View details for PubMedCentralID PMC11358159
-
Treatment of Lichen Planopilaris and Frontal Fibrosing Alopecia: A Retrospective, Real-Life Analysis in a Tertiary Center in Germany
JOURNAL OF CLINICAL MEDICINE
2024; 13 (16)
Abstract
Background: Lichen planopilaris (LPP) is an inflammatory cicatricial alopecia characterized by an irreversible destruction of the hair follicle resulting in its permeant destruction. The clinical presentation of LPP is a progressive patchy scarring alopecia. A variety of systemic agents is used to treat LPP with varying success. The aim of this retrospective, real-life analysis was to evaluate the treatment of hydroxychloroquine for LPP. Method: In this retrospective, single-center study, we analyzed 110 patients with LPP and frontal fibrosing alopecia (FFA) who received treatment over a 12-month period from March 2014 to March 2021 at the Department of Dermatology, University of Mainz Medical Center. Patient records were analyzed for response to treatment, co-morbidities, disease progression-free survival (DPFS), and safety. Clinical parameters associated with treatment response were determined with Cox regression modelling and logistic regression. Results: Overall, 77 of 110 patients were treated with a systemic agent. There was a clear association between LPP and the occurrence of Hashimoto thyroiditis. Topical treatment with corticosteroids did not improve clinical symptoms in the majority of patients (15 out of 101). In 71% of patients treated with systemic cyclosporine A and 62% of patients treated with hydroxychloroquine, we observed a significant resolution of the inflammatory process, which correlated with a robust durable clinical response (p < 0.001). Toxicity was observed in 17% (n = 9) of patients receiving systemic treatment with hydroxychloroquine and correlated with the duration of systemic treatment (p < 0.001). Treatment discontinuation was associated with a flare-up of clinical symptoms (29%), which required the re-initiation of second-line therapy in 13 out of 51 patients. Overall, the initiation of second-line treatment, either hydroxychloroquine or Cyclosporine A (CsA), yielded positive results, especially in the patient cohort treated with hydroxychloroquine (overall response rate, ORR = 100%), who showed disease progression during CsA or retinoids. Conclusions: Our results from this contemporary cohort of patients with LPP and FFA indicate that hydroxychloroquine and cyclosporine are effective systemic agents in decreasing clinical symptoms. However, our data also show that the discontinuation of treatment is often associated with the exacerbation of clinical symptoms. Response rates to second-line treatment were especially favorable in the patient cohort with hydroxychloroquine.
View details for DOI 10.3390/jcm13164947
View details for Web of Science ID 001306733700001
View details for PubMedID 39201087
View details for PubMedCentralID PMC11355652
-
Tumor-stroma contact ratio - a novel predictive factor for tumor response to chemoradiotherapy in locally advanced oropharyngeal cancer.
Translational oncology
2024; 46: 102019
Abstract
The growth pattern of oropharyngeal squamous cell carcinomas (OPSCC) varies from compact tumor cell aggregates to diffusely infiltrating tumor cell-clusters. The influence of the growth pattern on local tumor control and survival has been studied mainly for surgically treated oral cavity carcinomas on a visual basis. In this study, we used multiplex immunofluorescence staining (mIF) to examine the antigens pan-cytokeratin, p16INK4a, Ki67, CD271, PD-L1, and CD8 in pretherapeutic biopsies from 86 OPSCC. We introduce Tumor-stroma contact ratio (TSC), a novel parameter, to quantify the relationship between tumor cells in contact with the stromal surface and the total number of epithelial tumor cells. mIF tumor cores were analyzed at the single-cell level, and tumor-stromal contact area was quantified using the R package "Spatstat". TSC was correlated with the visually assessed invasion pattern by two independent investigators. Furthermore, TSC was analyzed in relation to clinical parameters and patient survival data to evaluate its potential prognostic significance. Higher TSC correlated with poor response to (chemo-)radiotherapy (r = 0.3, p < 0.01), and shorter overall (OS) and progression-free (PFS) survival (median OS: 13 vs 136 months, p < 0.0001; median PFS: 5 vs 85 months, p < 0.0001). Visual categorization of growth pattern according to established criteria of tumor aggressiveness showed interobserver variability increasing with more nuanced categories (2 categories: k = 0.7, 95 %-CI: 0.55 - 0.85; 4 categories k = 0.48, 95 %-CI: 0.35 - 0.61). In conclusion, TSC is an objective and reproducible computer-based parameter to quantify tumor-stroma contact area. We demonstrate its relevance for the response of oropharyngeal carcinomas to primary (chemo-)radiotherapy.
View details for DOI 10.1016/j.tranon.2024.102019
View details for PubMedID 38833784
-
Novel methods of multiparametric tissue diagnostics
ONKOLOGIE
2023; 29 (12): 1069-1077
View details for DOI 10.1007/s00761-023-01425-7
View details for Web of Science ID 001187929000001
-
Spatial Dissection of the Bone Marrow Microenvironment in Multiple Myeloma By High Dimensional Multiplex Tissue Imaging
AMER SOC HEMATOLOGY. 2023
View details for DOI 10.1182/blood-2023-189255
View details for Web of Science ID 001159306700086
-
Quantification of invasion patterns as a predictive factor for the therapeutic response of oropharyngeal squamous cell carcinoma to radiochemotherapy
SPRINGER HEIDELBERG. 2023: S35-S36
View details for Web of Science ID 001045118200063
-
Combination of immune-checkpoint inhibitors and targeted therapies for melanoma therapy: The more, the better?
Cancer metastasis reviews
2023
Abstract
The approval of immune-checkpoint inhibitors (CPI) and mitogen activated protein kinase inhibitors (MAPKi) in recent years significantly improved the treatment management and survival of patients with advanced malignant melanoma. CPI aim to counter-act receptor-mediated inhibitory effects of tumor cells and immunomodulatory cell types on effector T cells, whereas MAPKi are intended to inhibit tumor cell survival. In agreement with these complementary modes of action preclinical data indicated that the combined application of CPI and MAPKi or their optimal sequencing might provide additional clinical benefit. In this review the rationale and preclinical evidence that support the combined application of MAPKi and CPI either in concurrent or consecutive regimens are presented. Further, we will discuss the results from clinical trials investigating the sequential or combined application of MAPKi and CPI for advanced melanoma patients and their implications for clinical practice. Finally, we outline mechanisms of MAPKi and CPI cross-resistance which limit the efficacy of currently available treatments, as well as combination regimens.
View details for DOI 10.1007/s10555-023-10097-z
View details for PubMedID 37022618
-
Response to First-Line Treatment with Immune-Checkpoint Inhibitors in Patients with Advanced Cutaneous Squamous Cell Carcinoma: A Multicenter, Retrospective Analysis from the German ADOReg Registry.
Cancers
2022; 14 (22)
Abstract
Cutaneous squamous cell carcinoma (cSCC) is a common malignancy of the skin and has an overall favorable outcome, except for patients with an advanced stage of the disease. The efficacy of checkpoint inhibitors (CPI) for advanced cSCC has been demonstrated in recent clinical studies, but data from real-world cohorts and trial-ineligible cSCC patients are limited. We retrospectively investigated patients with advanced cSCC who have been treated with CPI in a first-line setting at eight German skin cancer centers registered within the multicenter registry ADOReg. Clinical outcome parameters including response, progression-free (PFS) and overall survival (OS), time-to-next-treatment (TTNT), and toxicity were analyzed and have been stratified by the individual immune status. Among 39 evaluable patients, the tumor response rate (rwTRR) was 48.6%, the median PFS was 29.0 months, and the median OS was not reached. In addition, 9 patients showed an impaired immune status due to immunosuppressive medication or hematological diseases. Our data demonstrated that CPI also evoked tumor responses among immunocompromised patients (rwTRR: 48.1 vs. 50.0%), although these responses less often resulted in durable remissions. In line with this, the median PFS (11 vs. 40 months, p = 0.059), TTNT (12 months vs. NR, p = 0.016), and OS (29 months vs. NR, p < 0.001) were significantly shorter for this patient cohort. CPI therapy was well tolerated in both subcohorts with 15% discontinuing therapy due to toxicity. Our real-world data show that first-line CPI therapy produced strong and durable responses among patients with advanced cSCC. Immunocompromised patients were less likely to achieve long-term benefit from anti-PD1 treatment, despite similar tumor response rates.
View details for DOI 10.3390/cancers14225543
View details for PubMedID 36428636
-
Impaired regulatory T cell-dendritic cell interactions contribute to autoimmunity in leukocyte adhesion deficiency type-1.
JCI insight
2022
Abstract
Leukocyte Adhesion Deficiency Type-1 (LAD-1) is a rare disease resulting from mutations in the gene encoding for the common beta-chain of the SS2 integrin family (CD18). The most prominent clinical symptoms are profound leukocytosis and high susceptibility to infections. At the same time, LAD-1 patients are prone to develop autoimmune diseases, but the molecular and cellular mechanisms that result in coexisting immunodeficiency and autoimmunity are still unresolved. CD4+FOXP3+ regulatory T cells (Treg) are known for their essential role in preventing autoimmunity. To understand the role of Treg in LAD-1 development and manifestation of autoimmunity we generated mice specifically lacking CD18 on Treg (CD18Foxp3), resulting in defective LFA-1 expression. Here we demonstrate a crucial role of LFA-1 on Treg to maintain immune homeostasis by modifying T cell - dendritic cell (DC) interactions and CD4+ T cell activation. Treg-specific CD18 deletion did not impair Treg migration into extra-lymphatic organs but resulted in shorter interactions of Treg with DC. In vivo, CD18Foxp3 mice developed spontaneous hyperplasia in lymphatic organs, and diffuse inflammation of the skin and in multiple internal organs. Thus, LFA-1 on Treg is required for the maintenance of immune homeostasis.
View details for DOI 10.1172/jci.insight.162580
View details for PubMedID 36346673
-
The Role of the Immune Phenotype in Tumor Progression and Prognosis of Patients with Mycosis Fungoides: A Quantitative Immunohistology Whole Slide Approach
CELLS
2022; 11 (22)
Abstract
Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphomas, characterized by mature, skin-tropic CD4+ T-helper cells. In order to study the immune tumor microenvironment in MF patients, we performed immunohistochemical stains on MF biopsies, digitized whole-slide tissue sections, and performed quantitative analysis of the different immune cell subsets to correlate tissue parameters with the clinical data of patients, such as progression-free survival or overall survival.Overall, 35 patients who were treated between 2009 and 2019 and for whom one or more paraffin tissue blocks were available have been included in the present study (58 tissue specimens in total). Conventional immunohistochemistry stains for CD3, CD4, CD8, CD20 and CD30 were used for the analysis of the immune phenotype, and quantitative analysis was performed using QuPath as a quantitative digital pathology tool for bioimage analysis of whole slides.Analysis of tissue parameters for prognostic significance revealed that patients with a stronger infiltration by CD8+ lymphocytes within the tumor cell compartment had a higher risk of disease progression (p = 0.031) and showed a shorter progress-free survival (p = 0.038). Furthermore, a significant association of the percentage of CD30+ cells (median: 7.8%) with the risk of disease progression (p = 0.023) and progression-free survival (p = 0.023) was found. In relation to the clinical features of our patient cohort, a higher risk of disease progression (p = 0.015) and a shorter progression-free survival (p = 0.032) for older patients (>61 years) were observed.Our results demonstrated the prognostic relevance of large-cell transformation in mycosis fungoides and its strong association with the presence of CD30+ lymphocytes. Unlike previous reports, our study suggests an adverse prognostic role for CD8+ T cells in patients with mycosis fungoides. Moreover, our data indicate that the immune phenotype within the tumor microenvironment shows strong temporal heterogeneity and is altered in the course of tumor progression.
View details for DOI 10.3390/cells11223570
View details for Web of Science ID 000887092100001
View details for PubMedID 36428999
View details for PubMedCentralID PMC9688439
-
Protease- and cell type-specific activation of protease-activated receptor 2 in cutaneous inflammation
JOURNAL OF THROMBOSIS AND HAEMOSTASIS
2022
Abstract
Protease-activated receptor 2 (PAR2) signaling controls skin barrier function and inflammation, but the roles of immune cells and PAR2-activating proteases in cutaneous diseases are poorly understood.To dissect PAR2 signaling contributions to skin inflammation with new genetic and pharmacological tools.We found markedly increased numbers of PAR2+ infiltrating myeloid cells in skin lesions of allergic contact dermatitis (ACD) patients and in the skin of contact hypersensitivity (CHS) in mice, a murine ACD model for T cell-mediated allergic skin inflammation. Cell type-specific deletion of PAR2 in myeloid immune cells as well as mutation-induced complete PAR2 cleavage insensitivity significantly reduced skin inflammation and hapten-specific Tc1/Th1 cell response. Pharmacological approaches identified individual proteases involved in PAR2 cleavage and demonstrated a pivotal role of tissue factor (TF) and coagulation factor Xa (FXa) as upstream activators of PAR2 in both the induction and effector phase of CHS. PAR2 mutant mouse strains with differential cleavage sensitivity for FXa versus skin epithelial cell-expressed proteases furthermore uncovered a time-dependent regulation of CHS development with an important function of FXa-induced PAR2 activation during the late phase of skin inflammation.Myeloid cells and the TF-FXa-PAR2 axis are key mediators and potential therapeutic targets in inflammatory skin diseases.
View details for DOI 10.1111/jth.15894
View details for Web of Science ID 000866278800001
View details for PubMedID 36161697