Fig. 3: Increased frequency of CD11c⁺Tbet^highCD21^low B cells in DS.

a, Representative t-distributed stochastic neighbour embedding (t-SNE) analysis of a fixed number of B cells to illustrate subset distribution in whole blood from adults with DS and age-matched HC individuals. b,c, The frequency in adults with DS (n = 10) and age-matched HC individuals (n = 10) of total B cells expressed as the percentage of CD66b⁻ cells (non-granulocytes) (b) and B cell subsets expressed as the percentage of total B cells (c). d–g, The frequency in HC adults (n = 10), adults with DS (n = 10) and patients with SLE (n = 6) of CD11c⁺ B cells in the IgD⁺ naive (CD27⁻CD38^lowIgD⁺) or DN (CD27⁻CD38^lowIgD⁻) compartments expressed as the percentage of total (d), IgD⁺ naive (e) or DN (f) B cells, and the log₂-transformed ratios of CD11c⁺ subsets to CD11c⁻ subset (rN:aN and DN2:DN1) (g). h–k, Intracellular Tbet expression (h), and surface expression of FAS and CD86 (i), CD21 (j) and CXCR5, CCR7, CCR4 and CXCR3 (k) in naive and DN B cells from both HC individuals (n = 2–4) and individuals with DS (n = 3–10). MSI, mean signal intensity; MFI, mean fluorescence intensity. l,m, Correlation of CD11c⁺ B cells and circulating IL-6 (l) and cT_FH1/17 (m). r, Pearson correlation coefficient. In b–g, the whiskers denote the minimum and maximum values, the box limits denote quartile 1 to quartile 3, and the centre bar denotes the mean. Significance was assessed using two-tailed unpaired t-tests (b and h–k) and one-way ANOVA with Tukey’s post hoc analysis (d–g).