Baseline data and antibody profiles in patients with SLE stratified by ancestral background
| African-Americans | Hispanic-Americans | European-Americans | Χ2 | P* | |
| Female (%) | 90.3 | 82.1 | 86.9 | 3.39 | 0.1839 |
| Age, mean±SD years | 39.9±14.7 | 22.8±14.7 | 39.6±18.2 | – | <0.0001 |
| ANA (%) | 98.1 | 95.5 | 99.0 | 2.49 | 0.2886 |
| Anti-dsDNA (%) | 42.6 | 46.3 | 42.4 | 0.31 | 0.8548 |
| Anti-Sm (%) | 39.4 | 25.4 | 15.2 | 19.77 | <0.0001 |
| Anti-RNP (%) | 67.6 | 29.9 | 22.2 | 68.10 | <0.0001 |
| Anti-Ro (%) | 55.6 | 35.8 | 33.3 | 17.09 | 0.0001 |
| Anti-La (%) | 19.4 | 6.0 | 12.1 | 8.18 | 0.0167 |
| APL (%) | 11.1 | 14.9 | 22.2 | 6.30 | 0.0350 |
| IFNα activity, median (IQR) | 5.3 (0.9–30.5) | 2.0 (0.7–16.7) | 1.4 (0.3–5.1) | – | <0.0001 |
*P values were derived from the Χ2 test statistic with two df for all variables, except for age and IFNα activity, which was calculated using one-way analysis of variance with a P value calculated from Kruskal-Wallis test.
Anti-dsDNA, antidouble-stranded DNA; APL, antiphospholipid; anti-RNP, antiribonucleoprotein; IFNα, interferon-α.