Prevalence of ankylosing spondylitis and HLA-B27 in a North American Indian population: a pilot study.

The value of an epidemiologic approach to the diagnosis of ankylosing spondylitis was assessed in a pilot study of an Amerind population. In 103 adult volunteers aged 20 to 42 years on a Cree reservation lumbar flexion and chest expansion were measured and HLA typing was performed on peripheral blood lymphocytes. Of the 14 subjects with HLA-B27, 2 had radiologic evidence of sacroiliitis but none could be said to have definite ankylosing spondylitis on clinical grounds.