Prevalence of antinucleosome antibodies by enzyme-linked immunosorbent assays in patients with systemic lupus erythematosus and other autoimmune systemic diseases.

The objective was to report our experience with the detection of antinucleosome antibodies (anti-Ncs Ab) in a series of systemic lupus erythematosus (SLE) patients, and to compare these results with those of antihistone and anti-double-stranded (ds) DNA antibodies. For this we selected 128 patients (106 females, 22 males, mean age 40 years) including 52 patients with SLE without organ involvement, 14 with lupus nephritis, 8 with neuropsychiatric lupus (NPSLE), 39 with systemic sclerosis (SSc), 15 with Sjögren syndrome (SS), and 51 healthy controls (38 females, 13 males, mean age 42 years). The sera were assayed for the levels of anti-ds DNA (ELISA), antihistone (INNO LIA ANA Update), anti-Ncs Ab (ELISA) and antinuclear antibodies (ANA-indirect immunofluorescence (IIF) on Hep-2 cells). The frequencies of positive anti-Ncs Ab, anti-ds DNA, and antihistone antibodies were in group of patients with SLE: 73%, 63%, and 54%, with SSc: 18%, 8%, 5%, and with SS: 3%, 3% and 0%, respectively. Patients with SLE have significantly increased levels of anti-Ncs Ab in their sera compared to healthy controls, SSc patients, and patients with SS. The concentration of the anti-Ncs Ab was 76 IU/mL in the SLE patients, 139 IU/mL in cases with lupus nephritis, 117 IU in NPSLE patients, 15 IU/mL in the SSc and 8 IU/mL in the healthy controls. All the three autoantibodies were present more frequently in cases with lupus and this correlation was significant in statistical means. Antinucleosome IgG antibodies seem to be a more sensitive marker of SLE than anti-ds DNA.