aGVHD and cGVHD delay the B-cell reconstitution but increase B-cell divisions. Mean (± standard error) of total number of sjKREC/blood mm³ (upper panels) measured by quantitative PCR before (pre-) and 3, 6, 12, and 24 months after allo-HSCT in patients with (dotted lines, n = 116) or without (plain lines, n = 127) aGVHD (left panel) or with (dotted lines, n = 117) or without (plain lines, n = 126) cGVHD (middle panel) and number of divisions (lower panels) were represented. Values were normalized for the genomic copy number, with albumin gene quantification.¹⁷  Mean number of B-cell divisions (n) was calculated using the following formulas: number of Cj’s = 2ⁿ × number of sjKRECs, or 2ⁿ = Cj/sjKREC, or nLOG2 = LOG(Cj/sjKREC), and finally, n = LOG(Cj/sjKREC)/LOG2. In right panels, “no” represents patients who developed no GVHD (n = 79); “acute only,” patients who developed aGVHD only (n = 47); “chronic only,” patients who developed cGVHD only (n = 48); and “both,” patients who developed aGVHD followed by cGVHD (n = 69). For lower right panel: at month 3, no vs acute *; at month 12, no vs chronic ***; no vs both * and acute vs chronic **; other combinations were NS. Shaded areas indicate values in healthy controls (n = 43). *P < .05; **P < .01; ***P < .001; NS, not significant (Mann-Whitney).