SNRPN and systemic lupus erythematosus: Cross-reactivity of autoantibodies against epitopes on SLE small nuclear ribonucleoprotein-associated protein B (SmB) and SmD with various domains of EBNA-1 has been reported in SLE, and lupus-like autoimmune disease appears in rabbits after immunization by EBNA-1 motif PPPGRRP (27–29).