The factors that trigger the development of extraarticular features of rheumatoid arthritis (RA) are still unknown. HLA-DR alleles such as HLA-DR4 and HLA-DR1 are associated with the risk to develop RA. A large scale study from Sweden and the Mayo Clinic suggests that HLA-DR4, but not HLA-DR1, is associated with the risk to develop extraarticular RA.
No takes yet. Share an insight, caveat, or question.
Jean Roudier (2006) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: