title: Seronegative arthritis, seronegative spondarthritis, reactive arthritis.
mesh_terms: D001168:Arthritis / Q000145:classification* / Q000235:genetics / Q000276:immunology; D006680:HLA Antigens / Q000235:genetics; D015796:HLA-B27 Antigen; D006801:Humans; D012217:Rheumatoid Factor / Q000032:analysis; D013167:Spondylitis, Ankylosing / Q000145:classification* / Q000235:genetics / Q000276:immunology
chemical_list: D006680:HLA Antigens; D015796:HLA-B27 Antigen; D012217:Rheumatoid Factor