Premium
Complement‐Fixing Intracellular Complexes of IgG Rheumatoid Factor in Rheumatoid Plasma Cells.
Author(s) -
MUNTHE E.,
NATVIG J. B.
Publication year - 1972
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1972.tb01813.x
Subject(s) - rheumatoid factor , rheumatoid arthritis , immunology , intracellular , antibody , synovial fluid , immunoglobulin g , extracellular , complement fixation test , chemistry , synovial membrane , medicine , pathology , biochemistry , serology , alternative medicine , osteoarthritis
Intracellular rheumatoid factor activity is found mostly in IgM plasma cells of rheumatoid synovial membranes from seropositive patients, while tissues from seronegative patients nearly always lack free rheumatoid factor. However, rheumatoid factor activity can be revealed in a considerable number of IgG plasma cells by pepsin digestion of tissues both from seropositive and seronegative patients. This activity has been further characterized by sequential double immunofluorescence staining. It was demonstrated in plasma cells representing each of the four IgG subclasses. The proportion of rheumatoid plasma cells with this activity varied in tissues from different individuals, but in some seronegative cases about 50% or more of the IgG plasma cells contained such‘hidden’ rheumatoid factor. Most of the IgG rheumatoid factors in plasma cells possessed the ability to react with several IgG subclass proteins, and were thus often directed against antigens common to two or more subclasses. The results gave evidence of intracellular blocking of rheumatoid factor activity, due to IgG‐IgG rheumatoid factor complexes. Additional evidence of such plasma cell complexes was obtained by observing an in vitro fixation of the complement components Clq and C3 to such cells. The fixation of aggregated IgG to extracellular deposits and to inclusions in synovial lining cells and joint fluid leukocytes was due to Clq as well as to rheumatoid factor.