title: Complement activating rheumatoid factors in rheumatoid arthritis studied by haemolysis in gel: relation to antibody class and response to treatment with podophyllotoxin derivatives.
abstract: Complement (C) activating rheumatoid factors (RF) were measured in 16 patients with rheumatoid arthritis (RA) by a simple haemolysis in gel (HIG) assay. IgM-RF, but not IgG-RF or IgA-RF, measured by an enzyme linked immuno-sorbent assay, were closely correlated with C activating RF (r = 0.86). In neither assay did the concentrations of RF appear to be directly related to C1 activation as expressed by serum concentrations of C1r-C1s-C1 inactivator complexes or of C4. In the sera, C1q binding substances, measured by C1q binding assay, were markedly correlated with C activating RF (r = 0.88), whereas C1q binding substances detected by the C1q deviation test were not. Treatment with podophyllotoxin derivatives for 6 months clearly reduced patients' RF concentrations. The decrease of IgG-RF, IgA-RF and IgM-RF was significantly more pronounced than that of the IgG, IgA and IgM concentrations, respectively.
mesh_terms: D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology; D003167:Complement Activation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006462:Hemolytic Plaque Technique; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis / Q000145:classification*; D008297:Male; D008875:Middle Aged; D011034:Podophyllotoxin / Q000031:analogs & derivatives*; D012217:Rheumatoid Factor / Q000032:analysis / Q000502:physiology*
chemical_list: D000936:Antigen-Antibody Complex; D007136:Immunoglobulins; D012217:Rheumatoid Factor; D011034:Podophyllotoxin