HLA associations of seropositive rheumatoid arthritis in a Cree and Ojibway population

Objective. To determine the HLA associations of seropositive rheumatoid art hritis(RA) in a Cree and Ojibway population; to determine whether specific alleles distinguish juvenile or adult onset. Methods, HLA-A, B, C, and DRB1 alleles were analyzed in 23 Ojibway and Cree patients with RA seen in a single tertiary care center, Comparisons were m ade with published results of controls and with results of 18 patients with rheumatoid factor (RF) positive polyarticular juvenile rheumatoid arthriti s (JRA) from the same population. Results. Comparisons among patients with RA, patients with RF positive poly articular JRA, and controls showed increased frequencies of the RA shared e pitope in patients with RA and of DRB1*0901 in patients with seropositive p olyarticular JRA, while the frequency of DRB1*08 alleles was decreased in p atients with RF positive polyarticular JRA, Conclusion. In this population, DRB1*0901 may promote while DRB1*08 alleles may protect against a juvenile onset of RA specifically. In contrast, the RA shared epitope may have a greater effect on the risk of adult onset sero positive RA. Due to the small patient numbers, these results require confir mation.