title: Hidden rheumatoid-factor in active seronegative rheumatoid arthritis.
mesh_terms: D000328:Adult; D000818:Animals; D000937:Antigen-Antibody Reactions; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology*; D002850:Chromatography, Gel; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis; D007841:Latex Fixation Tests; D008722:Methods; D011817:Rabbits / Q000276:immunology; D012217:Rheumatoid Factor / Q000032:analysis*; D012218:Rheumatoid Nodule / Q000276:immunology; D012756:Sheep / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor