FLG and rheumatoid arthritis: Berthelot et al. [7] noticed that Filaggrin and the Fc portion of the immunoglobulin, which are two major self-antigens in rheumatoid arthritis (RA), colocalize in HC cytoplasm as if these structures were involved in immune tolerance disruption toward these antigens or as if the cells that are composed of HC could play a role in antigen-presenting before degeneration.