in order to investigate whether a subgroup of ra is preferentially associated with dr4 , hla typing was performed in two groups of patients with severe extra-articular manifestations ( felty 's syndrome and histologically proved leucocytoclastic vasculitis ) , patients with severe joint destruction ( seropositive and seronegative ) , a group with only mild joint destruction , and in healthy controls .
C0003873
ra
C0015773
felty 's syndrome