Ploidy distribution of marrow megakaryocytes from patients with essential thrombocythemia.

Panels A1-10 show the ploidy distribution for each patient prior to anagrelide therapy. Increased MK ploidy was observed in all patients with a modal ploidy of 32N. Response to anagrelide was associated with decreased MK ploidy (corresponding panels B1-10). The modal ploidy was shifted from 32N to 16N as in healthy controls. The decreased ploidy correlated with a reduction in cell size and circulating platelet count.