title: Letter: HL-A B27 and modified bone formation.
mesh_terms: D005096:Exostoses / Q000276:immunology*; D006680:HLA Antigens / Q000302:isolation & purification*; D006649:Histocompatibility Antigens / Q000302:isolation & purification*; D006801:Humans; D013167:Spondylitis, Ankylosing / Q000276:immunology*; D013577:Syndrome
chemical_list: D006680:HLA Antigens; D006649:Histocompatibility Antigens