Spondylitis, AnkylosingRh-Hr Blood-Group SystemAntigens, CD1dSpondylitisIsoantibodiesH-2 AntigensHLA AntigensCarbodiimidesChloroformAntigensHLA-B27 AntigenAntigens, BacterialSacroiliac JointAntigens, NeoplasmAntigens, SurfaceAntigens, ViralSpineSpondylarthritisAntirheumatic AgentsHLA-B AntigensHLA-DR AntigensAntibodies, MonoclonalAntigens, ProtozoanSpondylarthropathiesAntigens, Polyomavirus TransformingImmunoglobulin GArthritisAntigens, FungalAntigens, CDArthritis, ReactiveBlood SedimentationSeverity of Illness IndexIritisHLA-A AntigensAntigens, HelminthTuberculosis, SpinalHistocompatibility AntigensArthritis, PsoriaticHistocompatibility Antigens Class IIRheumatic DiseasesEpitopesHistocompatibility Antigens Class IUveitis, AnteriorCarcinoembryonic AntigenAntigens, Viral, TumorBalneologyHistocompatibility TestingHLA-DQ AntigensArthritis, RheumatoidReceptors, Antigen, T-CellHLA-A2 AntigenCross ReactionsEnzyme-Linked Immunosorbent AssayT-LymphocytesHLA-D AntigensProliferating Cell Nuclear AntigenLumbar VertebraeKyphosisReceptors, Antigen, B-CellProstate-Specific AntigenO AntigensThoracic VertebraeAntibodies, BacterialAntigens, CD8Molecular Sequence DataLymphocyte ActivationAntigens, CD15Treatment OutcomeImmunoglobulin AAntigens, Tumor-Associated, CarbohydrateCervical VertebraeTumor Necrosis Factor-alphaSulfasalazineAllelesOsteitisAnti-Inflammatory Agents, Non-SteroidalHLA-DR4 AntigenAntigens, CD3Hepatitis B Surface AntigensBlood Group AntigensBack PainMice, Inbred BALB CReceptors, Tumor Necrosis FactorPseudarthrosisSpinal DiseasesAmino Acid SequenceHLA-DRB1 ChainsHLA-C AntigensGenetic Predisposition to DiseaseAntibody SpecificityImmune SeraKlebsiellaCell LineSacroiliitisB-LymphocytesPsoas Abscess