Autoimmune, anti-GP210 antibody detection
When detecting ANA by indirect immunofluorescence method using HEp-2 cells as a substrate, a peripheral fluorescent model can be detected in the serum of PBC patients, and its target antigen is a nuclear pore membrane glycoprotein with a molecular weight of 210kD, so , called GP210 protein, anti-GP210 protein has important diagnostic value for PBC. Clinically, ELISA is usually used for detection.
Anti-glycoprotein 210 antibodies (AGPA, anti-gp210, anti-nup210, anti-np210) target gp210 and are found at high frequency in patients with primary biliary cirrhosis (PBC). AGPA recognizes the cytoplasmic-facing carboxy-terminus (tail) of the protein. Although AGPA has only been found in a minority of PBC patients as a prognostic marker, those that do have a higher mortality rate and are predicted to have a poorer prognosis. Furthermore, patients who responded to ursodeoxycholic acid (UDCA) treatment and thus reduced AGPA failed to develop end-stage liver disease compared with an anti-gp210 Ab-naïve cohort. Nup210, a potential immune tolerance escape factor, is increased in the bile ducts of PBC patients with potentially damaging AGPA.
(PBC) Anti-mitochondrial, anti-centromere and anti-p62 antibodies were also found. When AGPA patients progressed to end-stage liver failure, those with anticentromere antibodies tended to develop portal hypertension, further suggesting a specific role for AGPA in PBC.
[Principle] Coat the purified nuclear envelope protein GP210 antigen on a polystyrene microwell plate. If there is an anti-GP210 antibody in the serum to be tested that can bind to it, wash to remove non-specific binding substances, and then add enzyme-labeled anti-GP210. Immunoglobulin antibody (also known as secondary antibody or anti-antibody, usually anti-IgG antibody), the antibody specifically binds to the antibody that has reacted with the solid-phase antigen, washes to remove unbound enzyme-labeled secondary antibody, adds substrate, enzyme It catalyzes the generation of color-developing products, and the depth of color development is proportional to the concentration of anti-GP210 antibody in the specimen.
[Reagents] Reagent composition: microwell plate coated with GP210 protein, enzyme-labeled secondary antibody, enzyme substrate solution, negative control, positive control, sample diluent and concentrated washing solution, etc.
[Operation] Operate according to the kit instruction manual or the SOP formulated by the laboratory. The main operation process is as follows: sample dilution→loading standard or sample→incubating reaction→washing→adding enzyme-labeled secondary antibody→incubating reaction→washing→display Color→terminate reaction→result interpretation.
【Result Judgment】
1. Qualitative detection If the degree of color development is lower than the cut-off value, the value is negative, and if it is higher than the cut-off value, it is positive.
2. Quantitative detection The absorbance value of the standard reaction well is detected by the microplate reader, and the absorbance-concentration standard curve is drawn, and the concentration of the anti-GP210 antibody can be found according to the standard curve.
【Reference interval】
1. Qualitative tests are usually negative for normal people.
2. For quantitative tests, each laboratory should establish its own reference interval. If the reference interval provided by the literature or instructions is used, it should be verified before use.
[Clinical Significance] Anti-GP210 antibody has certain sensitivity (38%) and high specificity (99%) for PBC, especially for the diagnosis of PBC negative for anti-mitochondrial M2 antibody. Therefore, the combined detection of anti-GP210 antibody and mitochondrial M2 antibody is of great significance for improving the detection rate of PBC.
