TRIM21 and systemic lupus erythematosus: Among SS and SLE sera used, those with reactivity to Ro/SSA and to native histones, respectively, showed significantly decreased ApoCell-phagocytosis (among SS sera: the anti-Ro/SSA-positive; median: 206, range: 118–320, the anti-Ro/SSA-negative; median: 356, range: 289–462, p = 0.0008, among SLE sera: the anti-histone-positive; median: 255, range: 209–300, the anti-histone-negative; median: 327, range: 245–450, p = 0.02).