JAK2 VG17F allele percentages in the MPDs. (A) Neutrophil JAK2 V617F allele percentages in the MPDs. Thirty-six ET and 77 PV patients were stratified by neutrophil JAK2 V617F allele percentage and disease duration. Boxes indicate the quartiles of the distribution; medians are indicated by black lines. All of the PV median neutrophil allele percentages were significantly greater than all of the ET median neutrophil allele percentages, regardless of disease duration (P = .008). Within ET or PV, the differences in allele percentages as a function of disease duration were not statistically significant. The JAK2 V617F allele percentage in the 8 IMF patients (median of 100, range of 48-100) could not be compared with the other groups because of the small sample size. (B) JAK2 V617F percentages in PV and ET neutrophils and platelets. Neutrophil genomic DNA and platelet cDNA were isolated simultaneously from blood samples in 23 PV and 13 ET patients. Circles indicate PV samples; triangles, ET. Median neutrophil JAK2 V617F allele percentage in PV (66%, gray bar) was greater than in ET (22%, black bar) (P < .001); median platelet JAK2 V617F allele percentage in PV (65%, gray bar) was greater than in ET (43%, black bar) (P = .002). In PV, the median neutrophil JAK2 V617F allele percentage was not significantly different (ns) from the platelet JAK2 V617F allele percentage, whereas in ET the platelet JAK2 V617F allele percentage was significantly greater than the neutrophil JAK2 V617F allele percentage (P = .001). Lines indicate cases in which JAK2 V617F was detected in platelet cDNA only. Neutrophil cDNA analysis yielded similar results (data not shown).