ANTI-DOUBLE STRANDED DNA, ANTIHISTONE, AND ANTI-NUCLEOSOME IGG REACTIVITIES IN CHILDREN WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

In this study we evaluated the presence of anti-nucleosome reactivity in children with systemic lupus erythematosus (SLE), and assessed its clinical correlations in comparison with anti-dsDNA and anti-histone I gG levels. Reactivities to nuclear substrates were determined by enzym atic immunoassays in 80 sera from 22 children with SLE, and solid phas e adsorption experiments were performed.In children with active SLE, t he anti-dsDNA, anti-histone, and anti-nucleosome IgG levels were eleva ted, and were significantly correlated with disease severity; during r emission anti-histone (but not anti-dsDNA and anti-nucleosome) antibod ies, although reduced, were still significantly elevated. The results of adsorption studies showed that anti-dsDNA antibodies contributed to anti-nucleosome reactivity, while anti-histone antibodies did not. Th e recognition of the H3H4-DNA nucleosome subparticle, rather than H2AH 2B-DNA, may be related to the nucleosome reactivity. In children with SLE anti-nucleosome reactivity is present; it is in part due to anti-d sDNA antibodies and in part to antibodies recognizing conformational e pitopes that may be related to the H3H4-DNA nucleosome subparticle. It s clinical significance for diagnosis is not greater than that of the anti-dsDNA antibodies.