Determination of IgA,IgG,IgM Class-Specific Rheumatoid Factor and Its Clinical Evaluation

Solid Phase enzyme-linked Immunosorbent assay(ELISA) for detectingclass-specific rheumatoid factor (RF) was established.Aggregated rabbit lgG was used ascoating antigen and the presence of RF was demonstrated by F(ab’)fragment of anti-humanIg conjugated to horseradish peroxidase(HRP).The results showed that high levels ofIgM-RF,IgG-RF and IgA-RF were found in patients with rheumatoid arthritis.A positive cor-relation existed between IgM-,IgG-,IgA-RF and disease activity.The presence of vasculitis al-so correlated positively with the levels of 3 class-specific RFs.