Objective: To investigate the association of rheumatoid vasculitis (RV) with the expression of the shared epitope, HLA-DRB1*04, DQA1, and DQB1 alleles.
Methods: A case-control study was designed to compare the frequency of the shared epitope, DRB1*04 alleles, DQA1, and DQB1 alleles of 31 patients with RV with that of 76 patients with rheumatoid arthritis (RA) without vasculitis. RV cases were discerned in subgroups according to presence or absence of minor skin vasculitis and major organ lesions. HLA-DRB1, DQA1, and DQB1 typing was performed by a polymerase chain reaction amplification and oligonucleotide hybridization.
Results: Overall, no associations were found between RV and the shared epitope, the DRB1*04 alleles, DQA1, or DQB1 alleles. The risk of developing RV with minor skin vasculitis (i.e., purpura or petechiae) was 10-20-fold increased in patients with DRB1*04, in particular in those homozygous for DRB1*04, and also in those with DRB1*0401. No such association was found for patients with major organ lesions.
Conclusion: The occurrence of vasculitis in RA is not associated with the shared epitope. DQA1, or DQB1 alleles. However, the risk of minor skin vasculitis is higher in patients carrying DRB1*04.