Significance of anti-nucleosome antibodies in diagnosis of systemic lupus erythematosus

Objective To evaluate the sensitivity and the specificity of antinucleosome antibodies(AnuA) and other autoantibodies in diagnosis of systemic lupus erythematosus(SLE).Methods Serum AnuA was measured by immunologic blotting in 65 patients with SLE,38 cases with other rheumatic diseases including rheumatoid arthritis,mixed connective tissue diseases,primary Sjogren syndrome,polymyositis,systemic sclerosis)and 30 healthy controls.Serum anti-dsDNA,anti-Sm,anti-histone antibody and other laboratory parameters were also measured.Results Seropositive rates for AnuA,anti-dsDNA and anti-Sm in 65 SLE patients were 58.5%,52.3% and 30.7% respectively,which were significantly higher than those in other rheumatic diseases(5.3%,0% and 7.9% respectively) and healthy controls(0%,0% and 0%)(P0.05).The sensitivity of AnuA in diagnosis of SLE was 58.5%,there was no significant difference with that of anti-dsDNA and anti-Sm(P0.05).and the specificity of AnuA in SLE was 97.1%,there was no significant difference with that of anti-dsDNA and anti-Sm(P0.05),while there was significant correlation between AnuA and anti-histone antibody(P0.05).AnuA was correlated with anti-dsDNA(P0.05),but not with anti-Sm(P0.05).The sensitivity of AnuA combined with anti-dsDNA and anti-Sm for SLE was 83.1%.The levels of Hb,C3 and C4 in AnuA positive patients were lower than those in AnuA negative patients(P0.05).Conclusion AnuA has high specificity and good sensitivity in diagnosis of SLE;AnuA combined with anti-dsDNA and anti-Sm might improve its diagnostic sensitivity.