Determination of IgA,IgG,IgM class—specific rheumatoid factors and its clinical evaluation

<正> Solid phase enzyme-linked immunosorbent assay（ELISA） for detectingclass-specific RF was established.Aggregated rabbit IgG is used as coating antigenand the presence of RF is demonstrated by F（ab'）2 fragment of anti-human Igconjugated to horseradish peroxidase（HRP）.The results showed that high levels ofIgM-RF,IgG-RF and IgA-RF were found in patients with rheumatoid arthritis butnot found in other patients.A positive correlation existed between IgM-,IgG-,IgA-RF and disease activity.The presence of vasculitis was also correlated positivelywith the levels of the 3 class-specific RF.