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Giant cell arteritis (GCA) is a granulomatous vasculitis affecting large arteries, especially the aorta and the extracranial branches of the external carotid artery. Its exact pathogenesis is not fully understood but major progress has been made in recent years, leading to new therapeutic targets like inhibition of the interleukin-6 pathway or the modulation of immune checkpoints. The cause of GCA has not been clearly identified but it is thought that GCA occurs on a genetic background and is triggered by unknown environmental factors that could activate and lead to the maturation of dendritic cells localized in the adventitia of normal arteries. These activated dendritic cells then produce chemokines which trigger the recruitment of CD4 + T cells, which in turn become activated, proliferate and polarize into Th1 and Th17 cells, which produce IFN-γ and IL-17, respectively. Exposed to IFN-γ, endothelial cells and vascular smooth muscle cells produce chemokines leading to the recruitment of further Th1 cells, CD8 + T cells and monocytes. The latter differentiate into macrophages, which, when persistently exposed to IFN-γ, form giant cells, the histological hallmark of GCA. With the contribution of vascular smooth muscle cells, immune cells then trigger the destruction and remodeling of the arterial wall, thus leading to the formation of a neo-intima resulting in progressive occlusion of the arterial lumen, which is responsible for the ischemic symptoms of GCA. In this paper, we review recent progress in our understanding of GCA pathogenesis in the fields of genetics, epigenetics, infections, immunology and vascular remodeling. [ABSTRACT FROM AUTHOR]

The immune repertoire (IR) refers to the sum of B cells and T cells with functional diversity in the circulatory system of one individual at any given time. Immune cells, which reside within microenvironments and are responsible for protecting the human body, include T cells, B cells, macrophages, and dendritic cells. These dedicated immune cells have a characteristic structure and function. T and B cells are the main lymphocytes and are responsible for cellular immunity and humoral immunity, respectively. The T cell receptor (TCR) and B cell receptor (BCR) are composed of multiple peptide chains with antigen specificity. The amino acid composition and sequence order are more diverse in the complementarity-determining regions (including CDR1, CDR2 and CDR3) of each peptide chain, allowing a vast library of TCRs and BCRs. IR research is becoming increasingly focused on the study of CDR3 diversity. Deep profiling of CDR3s using high-throughput sequencing is a powerful approach for elucidating the composition and distribution of the CDR3s in a given sample, with in-depth information at the sequence level. Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. To identify novel biomarkers for diagnosis and drug targets for therapeutic interventions, several groups attempted to describe immune repertoire characteristics of the liver in the physiological environment or/and pathological conditions. This paper reviews the recent progress in IR research on human diseases, including hepatocellular carcinoma, attempting to depict the relationships between hepatocellular carcinogenesis and the IR, and discusses the possibility of IR as a potential biomarker and therapeutic for hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]