Two to three months after transfer, recipients of αζDKO-Tregs manifested splenomegaly (Figure 10E), increased YFP− exTregs within the transferred CD45.2+CD4+TCRβ+ population (Figure 10F, 10G), increased CXCR5+PD-1+ Tfr-cells within the YFP+ population, increased CXCR5+PD-1+ exTreg-Tfh-cells within the CD45.2+CD4+TCRβ+YFP− exTregs (Figure 10H, 10I), and increased GC B-cells and IgG1+ cells within GC B-cells (Figure 10J, 10K). The gene discussed is CXCR5; the disease is Splenomegaly.