A, CD19+ peripheral blood B-cell depletion and repopulation during the second cycle of veltuzumab therapy. B-cell subsets were analyzed at 26 months, shortly after relapse from long-term remission. B, Long-term remission after the first cycle of veltuzumab correlates with the elevation of naive (CD19+CD27−) compared with memory (CD19+CD27+) B-cell frequencies. C, Long-term remission after the first cycle of veltuzumab correlates with the high levels (12.5%) of transitional (CD19+CD24+CD38+) B cells, as previously described.2