title: On the reassessment of the prevalence of As among B27 positive normal individuals.
mesh_terms: D006649:Histocompatibility Antigens / Q000032:analysis*; D006801:Humans; D013167:Spondylitis, Ankylosing / Q000453:epidemiology* / Q000235:genetics
chemical_list: D006649:Histocompatibility Antigens