An immune-mediated mechanism in the development of vascular lesions is suspected (Cid et al., 1994; Forbess and Bannykh, 2015) due to the prevalence of macrophages and CD4 + T lymphocytes in inflammatory infiltrates and to the clinical response to immunosuppressive drugs (Eleftheriou et al., 2013; Watanabe et al., 2016; James et al., 2018) .