Dual seropositivity and shared epitopes in RA: friends or foes? Dual seropositivity, RF and/or anti-citrullinated protein antibodies (ACPA) as well as shared epitope (SE) are known to be associated with poor prognosis and structural damage in RA. https://t.co/QcTHpgPV2Q https://t.co/TzueMr8M5T