IL-7 administration resulted in accelerated B-cell recovery in mice receiving T-cell–depleted BMT. Recovery of CD19⁺ B cells/μL was evaluated after T-cell–depleted (panel A, 2 groups of 21 mice each) and T-cell–replete (panel B, 2 groups of 15 mice each) BMT. Groups of mice were treated with PBS (□) or IL-7 (▪) at a dose of 500 ng twice daily on days 7 to 63. Absolute mean numbers (± SE) are depicted.