Changes in CD34+ Cells and CXCR4 levels. Data are shown as the geometric mean of change and error bars correspond to the 95% CI. (A) Change in circulating CD34⁺ cell count as a percentage of baseline values for the population enrolled as a whole. (B) Change in circulating CD34⁺ cell count as a percentage of baseline values in nonresponders only. (C) Change in circulating CD34⁺ cell count as a percentage of baseline values in responders only. (D) Change in CXCR4 expression as a percentage of baseline values.