While being constitutively expressed in the HEV of lymph nodes and other secondary lymphoid organs, the induction of PNAd has been reported in activated vessels in synovial biopsies from RA patients [23-26], in a model of Lyme disease arthritis in severe combined immunodeficient (SCID) mice infected with Borrelia burgdorferi (B. burgdorferi) [27], as well as in many other inflammatory lesions [28]. This evidence concerns the gene NTAN1 and rheumatoid arthritis.