Studies of rheumatoid arthritis among a tribe of Northwest Indians.

Thirty-six women from a Northwest Indian population known to have an increased prevalence of rheumatoid arthritis were studied. The course of the clinical disease was that of erosive rheumatoid arthritis with characteristic involvement of metacarpophalangeal and wrist joints. Rheumatoid factor and antinuclear antibody tests were frequently positive, and reactions to gold therapy were more frequent than in other rheumatoid populations. Viral antibodies were similar in the rheumatoid and the control groups. HL-A W24 and HL-A BW40 were increased in both the diseased and the control Indian populations.