Fig 6.

Ex vivo class-switch recombination defect of subjects carrying NFKB1 LOF variants is linked to the more extreme phenotype. Six-day culture of CFSE-labeled lymphocytes normalized for B-cell numbers: unstimulated, CpG/IL-2 stimulated (T cell–independent activation), or anti-IgM/anti-CD40/IL-21 stimulated (T cell–dependent activation). A, Percentage of divided B cells, as measured based on CFSE dilution. B, Percentage of CD27⁺⁺ plasmablasts. The gating strategy is shown in Fig E7, A. C and D, IgM and IgG production in supernatants of 6-day cultures. CA, Clinically affected subjects with an LOF variant in NFKB1; CU, clinically unaffected subject; HD, healthy donor. Only subjects with sufficient B cells could be analyzed. P values were determined by using 2-way ANOVA with the Bonferroni post hoc test. ns, Not significant. **P ≤ .01 and ***P ≤ .001.