Diagnostic value of anti-SA antibodies and antibodies to heterogeneous nuclear ribonucleoprotein K in rheumatoid arthritis

Annotation The aim of the research is to determine the levels and frequency of antibodies popularity to cyclic citrullinated peptide (APCCP), rheumatoid factor (RF), anti-Sa antibodies and antibodies to heterogeneous nuclear ribonucleoprotein K (anti-gRNP K) in rheumatoid arthritis (RA) and to compare their diagnostic characteristics, and also to determine sensitivity and specificity of anti-Sa antibodies, anti-hRNP K in seronegative RA. Material and methods. The study included 270 patients with RA and 50 healthy individuals. The levels of ACCP, anti-Sa, anti-hRNP K were assessed in blood serum samples from patients by enzyme-linked immunosorbent assay using commercial test systems. RF levels were assessed by kinetic nephelometry on automatic analyzer. Results. The levels and popularity frequency of the studied antibodies in patients with RА were significantly higher than in healthy individuals (p <0.05). Tests based on ADCP detection had the highest indices of sensitivity and specificity for RA diagnosis; sensitivity - 78.01%, specificity - 100.00%, and RF - 70.64%, specificity 96.97%. In case of serogegative APCCP and RA RF, diagnostic sensitivity of anti-Sa antibodies determination was 50.00%, specificity was 96.77%, sensitivity of anti-hRNP K antibodies determination was 55.56%, and specificity was 100.00%. Conclusion. Considering high specificity of tests for anti-Sa and anti-hRNP K antibodies in seronegative RA, they can be considered as additional confirmatory diagnostic tests.