Project description:BACKGROUND: Giant Cell Arteritis (GCA) causes severe inflammation of the aorta and its branches and is characterized by intense effector T cells infiltration. The roles that immune checkpoints play in pathogenesis of GCA are still unclear.Our aim was to study the immune checkpoints interplay in GCA. METHODS: First, we used VigiBase, the WHO international pharmacovigilance database, to evaluate the relationship between GCA occurrence and immune checkpoint inhibitors (ICI) treatments. We then further dissected the role of ICI in the pathogenesis of GCA, using immunohistochemistry, immunofluorescence, transcriptomics and flow cytometry on peripheral blood mononuclear cells (PBMCs) and aortic tissues of GCA patients and appropriated controls. RESULTS: Using VigiBase, we identified GCA as a significant immune related adverse event associated with anti-CTLA-4 (Cytotoxic T-lymphocyte-associated-protein-4) but not anti-PD-1/PD-L1 treatment. We further dissected a critical role for CTLA-4 pathway in GCA by identification of the dysregulation of CTLA-4-derived gene pathways and proteins in CD4+ T cells (and specifically Tregs) present in blood and aorta of GCA patients versus controls. While Tregs were less abundant and activated/suppressive in blood and aorta of GCA versus controls, they still specifically upregulated CTLA-4. Activated and proliferating CTLA-4+ Ki-67+ Tregs from GCA were more sensitive to anti-CTLA-4 (Ipilimumab)-mediated in vitro depletion versus controls. CONCLUSIONS: We highlighted the instrumental role of CTLA-4 immune checkpoint in GCA which provides a strong rationale for targeting this pathway.
Project description:To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls
Project description:Vasculitis is characterized by the inflammation of blood vessels. In patients with giant cell arteritis (GCA) large- to medium-sized vessels are affected. Single-cell RNA sequencing was performed on GCA patients and healthy controls (HC) to study the transcriptome of peripheral blood mononuclear cells of patients and controls.
Project description:Background: Kawasaki Disease (KD) is a childhood illness of suspected infectious etiology that causes medium-sized muscular arteritis, most critically affecting the coronary arteries. No single diagnostic test exists, hampering early diagnosis and treatment. Approximately 25% of untreated patients develop coronary artery disease, and children who are treated with intravenous gammaglobulin but do not respond are also at high risk. Subacute/chronic arteritis and luminal myofibroblastic proliferation are the pathologic processes occurring in KD CA after the second week of illness, when neutrophilic necrotizing arteritis has subsided. The specific dysregulated immune pathways contributing to subacute/chronic arteritis have been unknown, hampering the development of effective immunomodulatory therapies for patients not responding to intravenous gammaglobulin therapy. Methods and Results: Deep RNA sequencing was performed on KD (n=8) and childhood control (n=7) coronary artery tissues, revealing 1074 differentially expressed mRNAs. Molecular pathways involving T helper cell, cytotoxic T lymphocyte, dendritic cells, and antigen presentation were the most significantly dysregulated. There was significant upregulation of immunoglobulin and type I interferon-stimulated genes. 80 upregulated extracellular genes encoding secreted proteins are candidate biomarkers of KD arteritis. Conclusions: The immune transcriptional profile in KD coronary artery tissues is primarily T helper and cytotoxic lymphocyte-mediated, and has features of an antiviral immune response such as type I interferon-stimulated gene expression. This first report of the KD coronary artery transcriptome identifies specific dysregulated immune response pathways that can inform the development of new therapies for and biomarkers of KD arteritis, and provide direction for future etiologic studies.