Rheumatoid arthritis antigens homocitrulline and citrulline are generated by local myeloperoxidase and peptidyl arginine deiminases 2, 3 and 4 in rheumatoid nodule and synovial tissue.
Sanna TurunenJohanna HuhtakangasTomi NousiainenMaarit ValkealahtiJukka MelkkoJuha RisteliPetri LehenkariPublished in: Arthritis research & therapy (2016)
Rheumatoid nodules and synovia contain significant amount of PAD2, 3 and 4 and myeloperoxidase enzymes. These enzymes could explain the levels of citrulline and homocitrulline in seropositive RA synovial and rheumatoid nodule tissues especially around necrotic tissue.