The aim of this study was to examine the relationship between HLA-DP a
nd susceptibility to articular and extra-articular features (Felty's s
yndrome and vasculitis) of rheumatoid arthritis (RA). The possible ass
ociation of DP types with severity of articular disease was also analy
sed. No statistically significant associations were observed between H
LA-DP alleles and articular or extra-articular features of RA, or to t
he severity of the arthritis when p was corrected for the number of al
leles tested.