T-cell recovery and peripheral T-cell division after PSCT.

(A) Depicted are median numbers of CD4⁺ and CD8⁺ T cells and naive, memory, and effector CD4⁺ and CD8⁺ T-cell subsets (upper panels) and median values of Ki67 expression in CD4⁺ and CD8⁺ T cells and T-cell subsets (lower panels) at sequential time points after PSCT. Note that at 6 weeks, the percentage of naive CD4⁺ T cells was too low in most patients to determine Ki67 expression in this subset. Black circles, CD4⁺ (left panels) or CD8⁺ (right panels) T cells; white circles, naive T cells; white squares, CD27⁺memory T cells; white triangles, CD27⁻ memory T cells; white diamonds, CD27⁻ effector T cells. (B) The proportion of dividing CD4⁺ T cells did correlate significantly with the proportion of dividing CD8⁺ T cells, suggesting that division is driven by a common factor. (C) Patients with no signs of infectious diseases (group 1, n = 6) had lower proportions of dividing CD4⁺ T cells than patients with documented inflammatory complications, such as GVHD, reactivation of CMV, or fungal pneumonia (group 2, n = 8). Note that patient 12 was not assigned to either group because she was admitted to the hospital for severe dehydration at this time point (see Table 1). White circles, group 1 patients; cross-hair circles, group 2 patients (B, C). Horizontal bars indicate median values in panel C. Depicted in panels B and C are data obtained 6 weeks after PSCT (n = 15). Similar results were obtained for the other time points and for CD8⁺ T cells (data not shown).