Patients with early and late onset of B-cell reconstitution differ in B-cell subset regeneration kinetics. (A) Flow cytometrically determined cell counts of CD19⁺ B and CD3⁺ T cells, as well as CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cell subsets are shown separately for patients with an early (black line) or late (gray line) onset of B-cell reconstitution at indicated time points after allo-HSCT (early/late: D14, n = 14/9; D28, n = 19/16; D60, n = 17/13; D90, n = 19/15; D180, n = 11/7). (B) Graphs illustrate cell counts of indicated CD19⁺ B-cell subsets within 6 months after transplantation in patients with early (black line) and late (gray line) onset of B-cell reconstitution (early/late: D14, n = 14/9; D28, n = 19/16; D60, n = 17/13; D90, n = 19/15; D180, n = 11/7). Shown are mean values ± SEM. Statistically significant differences between the values of both patient groups are depicted. *P ≤ .05; **P ≤ .001. (C) Shown is the percentage of patients within the early or late onset patient group who displayed (left) no (light gray) or present (dark gray) systemic aGVHD and (right) who received reduced-intensity (light gray) or full-intensity (dark gray) conditioning therapy. Numbers in the pie charts indicate the percentage of patients within the respective group. Statistically significant association between onset of B-cell reconstitution and presence of systemic (left) aGvHD and (right) conditioning therapy were calculated with the 2-tailed Fisher exact test. P ≤ .05.