Antibodies to hnRNPA / B are mainly found in patients with RA, SLE, and MCTD. Other connective tissue diseases, especially in progressive systemic sclerosis (pSS), are rarely detected. In SLE, hnRNPA / B antibody, especially hnRNPAl antibody is closely related to U1-snRNP and / or Sm antibody. Because anti-U1-snRNP antibody can be detected in 20% to 30% of SLE and all MCTD patients, but it is rare in RA patients. Usually anti-hnRNP A / B and anti-UlsnRNP in the serum of RA patients do not appear at the same time. JIANGMEN XINXIN METAL PRODUCTS CO., LTD. , https://www.bbqoutdoorgrill.com
Anti-hnRNP-A2 / RA33 can appear early in the onset of RA, so it is helpful for early diagnosis, especially when the serum RF is negative. If the antibody is not detected, 'RA cannot be excluded. A positive hnRNPA / B antibody can exclude other joint diseases, such as psoriatic arthritis, ankylosing spondylitis and osteoarthritis. Although the role of anti-hnRNP A / B in the diagnosis of SLE and MCTD is still unclear, it can provide information for auxiliary diagnosis when anti-U1snRNP is weakly positive or the response is unclear.
The appearance of anti-hnRNP-A2 / RA33 has nothing to do with age, gender and disease stage. However, the positive rate is different in different populations. Compared with patients in central and western Europe, the RA33 positivity rate is very low among RA patients in Finland and Greece, while it is higher among non-Caucasian SLE patients.
In addition, the anti-hnRNP A / B protein has nothing to do with the activity and stage of the disease, and the antibody remains positive after remission. However, patients receiving steroid therapy for a long time, RA positive rate decreased.
The diagnostic sensitivity of anti-hnRNP-A2 / RA33 antibody to RA is 35%, and the specificity is about 85%. When the serum is only anti-hnRNP-A2 / RA33 positive without anti-Ul-snRNP, the specificity can be increased to 96%. .
The result of ELISA detection of anti-hnRNP-Al was 50% sensitivity and 85% specificity for RA, while the sensitivity of Western blot analysis was only 20% and specificity was 94%; when the serum was only positive for anti-hnRNP-A1 Without the anti-U1-snRNP this value can be increased to 98%.
In short, the autoantibodies against the A / B protein of hnRNP complex is a serological marker with high diagnostic value for RA. Although the positive rate of hnRNP antibody in RA is lower than RF, the specificity is higher than RF. These antibodies can also be detected in other related diseases (especially SLE and MCTD), but they often appear together with snRNP antibodies. There is a strong correlation between function and structure. For many years, patients with SLE and MCTD have been known to have autoimmune reactions on this microparticle (especially anti-Sm and anti-U1-snRNP). In contrast, only a few patients with RA have autoantibodies against snRNP. Therefore, it is only a hypothesis that the autoimmune response of spliceosome antibodies to SLE and MCTD is more specific, so it is not surprising to find antibodies against hnRNP protein in the serum of such patients. The detection of anti-hnRNP spliceosome-related antibody in the serum of RA patients indicates that this disease is more closely related to immunology than we originally thought. Therefore, this antibody forms a bridge between these three diseases, rather than a very valuable serum marker. So far, only hnRNPA / B protein can be used as a rheumatic autoimmune disease