Characterization of arterial dendritic cells in giant cell arteritis and polymyalgia rheumatica

Giant cell arteritis and polymyalgia rheumatica are two frequently overlap conditions. A pathophysiological continuum between these two diseases has been highlighted by the demonstration of activated dendritic cells in the arterial wall of PMR and GCA patients. However, in PMR, activation of these dendritic cells was not associated with inflammatory infiltration of the arterial wall. The aim of this study was to characterize arterial wall dendritic cells during PMR and GCA. BulK RNA sequencing was performed from FFPE sections of temporal artery biopsies from control (n = 3), PMR (n = 5) and GCA (n = 3) patients. Total RNA was extracted from FFPE tissue sections using the Maxwell RSC RNA FFPE kit (Promega). Ribosomal RNA-depleted RNA was used for library preparation with the NEBNext Ultra II Directional RNA library prep kit for Illumina (New England Biolabs). Libraries were paired-end sequenced (2*76 base pairs) on a NextSeq500 device (Illumina), with a read depth of 40 million. Kallisto software was used for quantifying transcript abundance from RNA-seq data against GRCh38 cDNA reference transcriptome from the Ensembl database, v96.