LACK OF TEMPORAL ASSOCIATION OF IRIDOCYCLITIS WITH IgG REACTIVITIES TO CORE HISTONES AND NUCLEOSOME SUBPARTICLES IN PAUCIARTICULAR JUVENILE CHRONIC ARTHRITIS

This study aimed to measure IgG reactivities to DNA-free nucleosomesubparticles (H2AH2B, H3H4) and nucleosome subparticles (H2AH2B–DNA,H3H4–DNA) and to evaluate the temporal relation of thesereactivities, as well as those to single core histones, withiridocyclitis (IC) in patients with antinuclear antibody positive(ANA +) pauciarticular juvenile chronic arthritis (JCA). Reactivitiesto nuclear substrates were determined by enzymatic immunoassaysin 120 sera from 45 children with ANA + pauciarticular JCA.Significantly elevated IgG levels to H3 and H4, to DNA-freenucleosome subparticles, and to the nucleosome subparticle H3H4–DNAwere present in patients with ANA + pauciarticular JCA; no evidenceof recognition of conformational epitopes was found. In bothhorizontal and follow-up studies, no relation between the reactivitiesstudied and the development, presence, or history of IC wasfound. Our results show the absence of a relation of antibodiesto histone molecules or to nucleosome subparticles with IC inpatients with ANA+ pauciarticular JCA. KEY WORDS: Juvenile chronic arthritis, Antinuclear antibodies, Iridocyclitis ^*Present address: Laboratorio Biotecnologie e Tecnologie Biomediche,IRCCS Policlinico San Matteo, 27100 Pavia, Italy.