WBC, neutrophil, B-cell, and NK cell counts before and after treatment for HD. Shown are the medians and interquartile ranges (error bars) of the absolute counts for the white blood cells, neutrophils, B cells, and NK cells in the same groups as shown in Fig 2. Significant differences between the healthy controls and any of the other groups are shown along the top; significant differences between the HD patients before treatment and the posttreatment HD subjects are shown below this.