BAFF is a key survival factor for Spl-PCs on B-cell depletion in AID-Cre-EYFP mice. (A) Quantification of BAFF concentration in culture supernatants of 4 × 10⁶ total spleen cells from control (n = 5) and anti-CD20–treated mice (n = 6) after 3 days (ELISA). (B) Quantification of APRIL concentration in culture supernatants of 4 × 10⁶ total spleen cells from control (n = 6) and anti-CD20–treated mice (n = 7) after 3 days (ELISA). (C-E) Number of residual EYFP⁺ cells observed at the nadir of B-cell depletion (or at equivalent time points) in controls (n = 12), anti-CD20– (n = 14), anti-CD20/anti-BAFF– (n = 8), and anti-BAFF–treated (n = 4) mice: EYFP⁺ B220⁺ splenic B cells (C), EYFP⁺ B220⁻ Spl-PCs (D) and EYFP⁺B220⁻ BM-PCs (E) (see protocol in supplemental Figure 2B). Analysis originates from ≥2 independent tamoxifen-labeling experiments, except for the anti-BAFF group. Significant differences are estimated by Mann-Whitney U test or 1-way ANOVA, Dunn test for multiple comparisons (*P < .05; **P < .01; ***P < .001; ****P < .0001). Mean values are indicated.