Figure 3.

Distribution of κ⁺λ⁺ B cells among human B cell subsets. (A) Representative flow cytometric analysis and gating strategy of human CD19⁺ B cell subsets in PBMCs. All B cell subsets, except for the CD38^highCD27^high (PBs&PCs) subset representing plasmablasts (PBs) and plasma cells (PCs), were analyzed for surface (s) Igκ and Igλ expression, and the frequency of κ⁺λ⁺ cells was measured only on cells positive for sIgκ and/or sIgλ, as shown for the CD38vsCD24 plot. For the CD38^highCD27^high (PBs&PCs) subset, Igκ and Igλ were measured after cell fixation and permeabilization and, therefore, include intracellular (IC) expression. (B) Frequency of κ⁺λ⁺ cells within each B cell subset from healthy controls (N=18), and from SLE patients with low (SLE-L, N=12) and high (SLE-H, N=6) frequency of κ⁺λ⁺ cells. Data were collected over a total of 18 independent analyses. Each symbol is a subject, and bars represent mean+SD. Differences between groups were analyzed by a two-tailed Mann-Whitney U test. Differences between the HC group and each of the SLE groups are reported on top of each SLE bar. Differences between the transitional B cell subset and the other B cell subsets only in the SLE-H group, are depicted with horizontal lines on top of graph, and only if significant. *p ≤ 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001; ns, not significant.