The use of one-step immunoblotting to detect both anti-RA33 and anti—ENA antibodies,and its diagnostic value for RA patients

Objective To improve the diagnostic specificity of anti-RA33 antibody for rheumatoid arthritis(RA).Methods Establishment of one-step immunoblotting technique to detect both anti-RA33 and anti-ENA antibodies simultaneously,and 266 sera from different rheumatic patients were detected.Results The positive rate of anti-RA33 antibody was 38.0%(38/100) in RA,35.8%(24/67) in SLE,36.4%(8/22) in MCTD,8.3%(3/36) in SS respectively.Among these anti-RA33 positive sera,anti-Sm/u1RNP bands were determinated in 95.8%(23/24) SLE,100%(8/8) MCTD respectively,and anti-SSA/SSB bands were determinated in 100%(3/3) SS sera.In contrast,none of the anti-ENA bands above were found in RA sera.Conclusion The one-step immunblotting in this study is extremely useful to serologically differentiate anti-RA33 positive RA from anti-RA33 positive SLE and MCTD patients.