What Is the Rheumatoid Factor?

Rheumatoid factor (RF) is an antibody against the determinant of the Fc fragment of human or animal IgG molecules. It is an autoantibody with denatured IgG as the target antigen. RF was originally discovered by Rose et al. (1948) in the serum of patients with rheumatoid arthritis (RA). There are B-cell clones that produce RF in RA patients. RF can be synthesized in large quantities under the direct action of denatured IgG or EB virus. RF is mainly IgM autoantibodies, but there are also IgG, IgA, IgD and IgE. There are many methods for detecting RF. The latex agglutination test and ELISA method are commonly used. The latex method mainly measures IgM type RF. The ELISA method can be used to determine RF of different Ig types, and it can also achieve quantitative detection, which is more practical.

Rheumatoid factor (theumatoid factor, RF) is an anti-human or animal IgG molecule Fc fragment

Rheumatoid factors are mostly IgM antibodies that bind to the Fc segment of anti-IgC. They mainly bind to immune complexes rather than monomeric IgC, and promote the clearance of immune complexes in the blood through this and immune complexes. , And deposition in the tissue. The role of rheumatoid factor in glomerulonephritis is unknown, but glomerulonephritis is rarely complicated by rheumatoid arthritis. However, rheumatoid factor can be detected from ICGN. This finding suggests that rheumatoid factors can aggravate the deposition of immune complexes in the glomeruli, but the properties of the antigen and primary antibodies determine the ability of the complexes to deposit in the kidney ^[2]

Its clinical significance is as follows:

When rheumatoid factor content exceeds a certain titer (1: 160), it is called rheumatoid factor positive. Alternatively, rheumatoid factor exceeds the upper limit of normal value (normal value is 0 to 20 units / ml), which is called high rheumatoid factor (positive) ^[3]

Normal: 1:16, Suspicious: 1:32, positive.