Clinical value of multiplex immune assay of antinuclear antibodies in systemic lupus erythematosus.

: A promising trend in the diagnosis of systemic autoimmune diseases is the multiplex immune assay (MIA) of autoantibodies and other laboratory biomarkers using microchips. The aim of the work was to study the diagnostic and prognostic significance of MIA antinuclear antibody (ANA) profiles in systemic lupus erythematosus (SLE). 94 patients with SLE, 70 patients with other rheumatic diseases and 30 healthy donors were examined. ANA (antibodies to doublestranded - dsDNA, Sm, SS-A/Ro, SS-B/La antigens, nucleosomes, ribosomal protein P-RibP and ribonucleoprotein - RNP-70) were determined in the serum by MIA using the xMAP technology. In MIA, antibodies to dsDNA, Sm and RibP have a high diagnostic specificity (Sp) (95.0-99.0%) and a likelihood ratio of positive results (LR+) (9.67-15.0), i.e. are the most "useful" diagnostic tests, and antibodies to RNP-70, SS-A/Ro and nucleosomes are classified as "useful" tests for the diagnosis of SLE (Sp: 84.0-95.0%, LR+> 2.0). Determination of profiles from 3 or more antigen-specific ANA by MIA increases the Sp method to 98.0-100%, and the LR+ - to the maximum values. Profiles from 7 subpopulations of ANA (antibodies to dsDNA, Sm, RibP, SS-A/Ro,SS-B/La, nucleosomes and RNP-70, 57.9%, 71.9%, 82.5%, 61.4 %, 84.2%, 50.9%, 84.2%) were found in the chronic variant of SLE. In the acute course of the disease, 4 subpopulations of ANA are simultaneously detected (antibodies to dsDNA, Sm, SS-A/Ro and nucleosomes, 77.3%, 45.5%, 40.9% and 72.7%); in subacute course there are 2 subpopulations of ANA (antibodies to dsDNA and nucleosomes, 53.3% and 46.7%). The activity index of SLEDAI-2K positively correlates with the concentration of antibodies to dsDNA (r = 0.55, p < 0.05), nucleosomes (r = 0.65, p < 0.05), RibP (r = 0.32; p < 0.05) and Sm (r = 0.36, p < 0.05) in the blood. There was no reliable relationship between the production of varieties of ANA and the index of organ damage. Mucocutaneous disorders, lupus-nephritis and neurolupus were most often associated with the detection of antibodies to dsDNA (53.2-64.0%), nucleosomes (55.3-66.0%), SS-A/Ro (38.0-40.4%) and Sm (27.8-36.2%). MIA of ANA profiles is an important tool for implementing a personalized approach to diagnosis, evaluation of activity, course and clinical and immunologic subtypes of SLE.