Significane of determining antinuclear antibodies in systemic connective tissue disorders in children

Abstract

Systemic connective tissue diseases (SCTD) are characterized by systemic autoimmune inflammation and are accompanied by development of antinuclear antibodies (ANA). Our aim was a comparative analysis of ANA in blood serum in children with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). The study included 50 patients with SLE, 50 patients with RA who were treated at the National Medical Research Center of Childrens Health. Median age was 12,2 y. o. (9-15.5). The titers of ANA and the cell fluorescence type were determined with the indirect immunofluorescence reaction (IFR) using the HEp-2 cell line (Immco Diagnostics, Inc, USA), as well as the concentration of antibodies to double-stranded DNA (adsDNA) in blood serum samples of the children detected by immunochemiluminescence (ICM) woth Elia dsDNA (Thermo Fisher Scientific, USA). A positive ANA titer and adsDNA were found, respectively, in 98% and in 48% in children with SLE. A positive ANA titer and adsDNA was detected in 100% and in 4% of children with RA, respectively. Highly positive ANA titers ( 1/1280) have been detected in 68% of children with SLE, and in 30% of children with RA. None of the RA patients with highly positive ANA titers had adsDNA. But, in patients with SLE, highly positive ANA titers and a positive dsDNA level were simultaneously detected in 16% of cases. There are both single types of cell fluorescence and their combinations in children with SLE and RA. Nuclear dot-like fluorescence was more common in children with SLE, cytoplasmic type, in children with RA, nucleolar type of glow was found only in children with RA. The revealed combinations of ANA and adsDNA titers in children with SLE and RA confirm the need for simultaneous use of RNIF and ICM.