Blood B10-cell frequencies in patients with autoimmune disease. (A) Representative B-cell cytoplasmic IL-10 expression by control (Ctrl) persons, and lupus (SLE), rheumatoid arthritis (RA), Sjögren syndrome (SjS), blistering skin disease (BD), and multiple sclerosis (MS) patients with relatively high B10-cell frequencies after in vitro CpG + PIB stimulation for 5 hours. B10 + B10pro cell maturation was induced by 48-hour CD40L + CpG stimulation, with PIB added during the final 5 hours of culture. Percentages indicate IL-10⁺ B-cell frequencies among CD19⁺ B cells. (B) IL-10⁺ B-cell frequencies as in panel A, with each dot representing single persons. Horizontal bars represent group means. The solid horizontal lines represent means plus 2 SD (95% confidence interval) for controls; and dashed lines, means plus 2 SD for all values. The patients are described in Table 1. Significant differences between means of patient groups and healthy controls are indicated: *P < .05; **P < .01. (C) Relative frequencies of B10 cells and B10 + B10pro cells identified for control persons and patients with autoimmune disease as in panel B compared after CpG or LPS stimulation, with each dot representing a person. (D) Relationship between cytoplasmic IL-10 expression levels and B10 + B10pro-cell frequencies in control persons and patients after stimulation with CD40L + CpG, with PIB added during the final 5 hours of 48-hour cultures. Linear mean fluorescence intensities (MFI) for IL-10⁺ and IL-10⁻ B cells were determined using the gates indicated in panel A with the values shown representing a ratio of IL-10⁺ to IL-10⁻ MFIs. A linear regression line (± 95% prediction bands, dashed lines) is shown for reference.