Objective: To study the serologic manifestations of rheumatoid arthritis (RA) at a United States Public Health Service Hospital that serves numerous tribes in Oklahoma.
Methods: Forty-five patients with RA were identified, and serologic studies for antinuclear antibody (ANA), rheumatoid factor, and antibodies to extractable nuclear antigens were performed. Extraarticular manifestations of RA were also evaluated.
Results: Twelve of the 45 patients with RA were Kiowa. These patients were significantly more likely to have a positive ANA (75%) than the other patients with RA (28%). In addition, anti-Ro was significantly more common among Kiowa (33%) than among members of other tribes (3%). There was no difference in the extraarticular manifestations of the Kiowa compared with the other Native American tribes.
Conclusion: RA can be distinctly characterized by serology among groups of American Indians living in the same geographic area.