IFNA1 and systemic lupus erythematosus: Moreover, using matched SLE serum and plasma, IFN activity levels showed a significant correlation (IFN-I, r2 = 0.866, p < 0.0001; IFN-II, r2 = 0.777, p < 0.0001; IFN-III, r2 = 0.745, p < 0.000.1) (Figure S1), indicating that blood processing has minimal effect on IFN concentrations, which is consistent with previous reports.27