Rheumatoid FactorArthritis, RheumatoidImmunoglobulin MImmunoglobulin GAntigen-Antibody ComplexPeptides, CyclicCryoglobulinsAutoantibodiesCryoglobulinemiaAntibodies, AntinuclearLatex Fixation TestsAntibodies, Anti-IdiotypicNephelometry and TurbidimetryImmunoglobulin AImmunoglobulin IdiotypesRheumatoid NoduleSjogren's SyndromeSynovial FluidAntirheumatic AgentsRheumatic DiseasesPrecipitinsEnzyme-Linked Immunosorbent AssayArthritisImmunoglobulin Fc FragmentsBlood SedimentationCitrullineCross ReactionsHLA-DR4 AntigenComplement Fixation Testsgamma-GlobulinsFalse Positive ReactionsComplement C1Arthritis, JuvenileAntibody SpecificityArthrographyHemagglutination TestsEndocarditis, Subacute BacterialHLA-DRB1 ChainsSynovitisImmunoglobulin AllotypesImmunoglobulin Gm AllotypesVasculitis, Leukocytoclastic, CutaneousHLA-DR AntigensComplement Activating EnzymesAutoimmune DiseasesImmunoglobulinsStaphylococcal Protein AJointsCollagen DiseasesBiological MarkersB-LymphocytesImmunoglobulin Heavy ChainsImmunoglobulin Variable RegionBinding Sites, AntibodyJoint DiseasesFelty SyndromeLupus Erythematosus, SystemicComplement C1qAntibodies, MonoclonalSyphilis, CongenitalImmunoglobulin IsotypesComplement ActivationEpitopesVasculitisSeverity of Illness IndexImmunoassayComplement System ProteinsComplement C3Mice, Inbred MRL lprProtein Tyrosine Phosphatase, Non-Receptor Type 22HybridomasImmunoglobulin Light ChainsComplement C4Immunoglobulin kappa-ChainsConnective Tissue DiseasesRubella virusAutoantigensGenes, ImmunoglobulinBlood Protein DisordersFluorescent Antibody Technique