PROCR and temporal arteritis: B cells are found in the adventitia of TAK artery and appear to be in a larger number compared with that in GCA samples, implying their involvement in the disease process in TAK.[67] Moreover, the number of CD19+/CD20-/CD127high antibody secreting B cells is significantly higher in TAK patients with active disease.[73] Mutoh et al. [74] identified two autoantibodies in Japanese TAK patients: anti-endothelial protein C receptor (EPCR) and anti-scavenger class B type I (SR-BI) antibodies; several features of these two autoantibodies indicate that they are likely to be pathogenic for TAK.