Diagnostic value of antibody immunoblotting detection in rheumatoid arthritis patients

Objective. To assess the diagnostic value of antinuclear antibody (ANA) profiling in rheumatoid arthritis by immunoblotting.
Materials and methods. In total, 46 patients with rheumatoid arthritis (RA) with a mean age of 34.6 years (21.3–63.2) were observed. The disease duration was 11.2 years (3.7–19.8); the activity according to DAS 28 was 3.15 ± 1.36 (3.05–3.61) points. The RA diagnosis was based on generally accepted clinical guidelines. The control group included 28 patients with osteoarthritis. Laboratory examinations were conducted using a set of reagents to determine IgG antibodies to nuclear antigens by immunoblotting.
Results. The RA patients showed an increased level of antibodies to the RNP/Sm antigen, with its frequency being significantly higher than in the control group (p = 0.007). The most specific testomes for diagnosing RA were anti-RNP/Sm (specificity 96%, sensitivity 25%) and antibodies to the recombinant antigen (sensitivity 25%, specificity 88.1%). The method of ROC analysis found that the value of anti-RNP/Sm = 0 is the point corresponding to the optimal ratio of sensitivity/specificity. This value corresponds to a sensitivity of 50% and a specificity of 73.8%.
Conclusion. The studied laboratory tests, as a rule, showed high specificity, but rather low sensitivity. The most specific test for RA is anti-RNP/Sm. The conducted ROC analysis showed that the anti-RNP/Sm test has an average quality index for diagnosing RA.

1. Alexandrova EN, Novikov AA, Nasonov EL. Federal clinical guidelines. Laboratory diagnosis of rheumatic diseases, Moscow: Geotar-Media, 2015 (In Russ.).

2. Agmon-Levin N, Damoiseaux J, Kallenberg C, Sack U et al. International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies. Ann Rheum Dis. 2014;73(1):17–23. doi: 10.1136/annrheumdis-2013-203863

3. Lapin SV, Mazing AV, Bulgakova TV, Surkova EA, Blinova TV, Holopova IS, Napalkova OS, Lerner MYu, Totolyan AA, Emanuel' VL. Clinical guidelines for the laboratory diagnosis of autoimmune diseases, Moscow, 2014 (In Russ.).

4. Alekseeva EI, Dvoryakovskaya TM, Nikishina IP, Denisova RV, Podchernyaeva NS, Suhorukih OA & Shubina LS. Systemic lupus erythematosus: clinical recommendations. Part 1. Current Pediatrics. 2018;17 (1):19–37 (In Russ.).

5. Soloviev SK, Aseeva EA, Popkova TV, et al. Systemic lupus erythematosus: new horizons for diagnosis and therapy. Rheumatology Science and Practice. 2020;58 (1):5–14 (In Russ.).

6. Sutton EJ, Davidson JE, Bruce IN. The systemic lupus international collaborating clinics (SLICC) damage index: a systematic literature review. Semin Arthritis Rheum. 2013;43(3):352–61. doi: 10.1016/j.semarthrit.2013.05.003

7. Aringer M, Costenbader K, Daikh D, Brinks R, Mosca M, Ramsey-Goldman R, Smolen JS, Wofsy D, Boumpas DT, Kamen DL, et. al. 2019 European League Against Rheumatism/American College of Rheumatology classification criteria for systemic lupus erythematosus. Ann Rheum Dis. 2019; 78(9):1151–9. doi: 10.1136/annrheumdis-2018-214819

8. Choi MY, Cui J, Costenbader K, et al. Different indirect immunofluorescence ANA substrate performance in a diagnostic setting of patients with SLE and related disorders: retrospective review and analysis. Lupus Science &Medicine 2020;7:e000431. doi: 10.1136/lupus-2020-000431

9. Pisetsky DS. Antinuclear antibody testing – misunderstood or misbegotten? Nat Rev Rheumatol. 2017;13(8):495–502. doi: 10.1038/nrrheum.2017.74

10. Damoiseaux J, von Mühlen CA, Garcia-De La Torre I, Carballo OG, de Melo Cruvinel W, Francescantonio PL, Fritzler MJ, Herold M, Mimori T, Satoh M, Andrade LE, Chan EK, Conrad K. International consensus on ANA patterns (ICAP): the bumpy road towards a consensus on reporting ANA results. Auto Immun Highlights. 2016;7(1):1. doi: 10.1007/s13317-016-0075-0

11. Konieczna I, Relich I, Durajski M, Lechowicz L, Chrapek M, Gaweda J, Fraczyk J, Kaminski ZJ. Novel tool in rheumatoid arthritis diagnosis-The usage of urease flap region peptidomimetics. J Pept Sci. 2018;24(6):e3084. doi: 10.1002/psc.3084