Antinucleosome Antibody in Children and Adolescents with Systemic Lupus Erythematosus

Abstract
Background: SLE is an autoimmune disease of unknown etiology characterized by the production of abroad and heter-ogeneous group of autoantibodies. These autoantibodies are directed to nuclear, cytoplasmic, and cellular membrane antigens. Recently, it was proposed that the nucleosome is the principal antigen in the pathophysiology of SLE, and that anti-Nuc antibodies are associated with organic damage.
Aim of the Study: The aim of this work was to study the potential utility of serum levels of anti- nucleosome antibodies as a diagnostic tool and a disease activity marker in children and adolescents with systemic lupus erythematosus.
Patients and Methods: The study was carried out on forty five patients with SLE who attended to the outpatient clinic and inpatient of Pediatric Nephrology matched age and sex served as a control group. All studied children were subjected to full history, complete physical examination, SLEDAI score, routine laboratory investigations and anti-dsDNA and anti-nucleosome antibody IgG assay. Data was analyzed by using SPSS.
Results: The mean serum level of anti-Nuc antibody was significantly higher in patients than controls (p-value <0.001). But there was no significant difference between patients' subgroups. There was a weak correlation between serum anti-Nuc antibody and SLEDAI score (r: 0.213) but strong corre-lation between anti-dsDNA antibody and SLEDAI score (r: 0.711). Anti-Nuc antibody showed higher sensitivity but equal specificity to anti-dsDNA antibody for the diagnosis of SLE.
Conclusion: Anti-nucleosome antibodies are superior to anti-dsDNA antibodies in the diagnosis of SLE especially in anti-dsDNA negative patients as they have higher sensitivity but as regard to disease activity antidsDNA antibody is more accurate.