Longitudinal measurement of mutation allele frequency in TET2 mutant PBMC samples. Variant allele frequencies (left y-axis) are shown in the 5 recurrently mutated genes as measured by targeted sequencing and plotted with leukemic burden as assessed by absolute lymphocyte count (ALC; right y-axis). (A) Four untreated samples showing long-term persistence of TET2 mutant clones. The boxed data points are from NK-enriched samples, and thus allele frequencies are skewed higher. (B) Four samples that received treatment with CP for 9 or 5 months as indicated, showing complete reduction of the mutant clone and lymphocyte counts in treated individuals. Pred, prednisone; unk., unknown.