Normal platelet counts mask abnormal thrombopoiesis in patients with chronic myeloid leukemia.

Increased platelet heterogeneity has been reported in myeloproliferative neoplasms (MPN) with thrombocytosis. However, whether abnormal thrombopoiesis occurs in patients with chronic myeloid leukemia (CML) who have normal platelet counts, remains unclear. In order to explore this question, 25 patients with CML with normal platelet counts (CML-N), 40 patients with CML with elevated platelet counts (CML-E) and 33 healthy adults were recruited. The association of platelet count with mean platelet volume (MPV), platelet large cell ratio (P-LCR) and platelet distribution width (PDW) was examined. Bone marrow smears were also reviewed to assess the proliferation and abnormal lobation of megakaryocytes. The results showed that the two CML groups exhibited higher MPV, P-LCR and PDW values than those of the controls (P<0.05). Furthermore, the CML-N group was more heterogeneous in terms of thrombopoiesis than the CML-E group, as demonstrated by a higher PDW (P<0.05) and higher ratio of multinucleated dysmegakaryocytes (12.17 vs. 4.69%; χ2=29.79; P=0.000). In addition, no correlation between platelet count and MPV, P-LCR or PDW was observed in the CML-N group (r=-0.102, -0.051 and -0.049, and P=0.619, 0.828 and 0.810, respectively). The results suggested that patients in the CML-N group have more heterogeneous thrombopoiesis of megakaryocytes and platelets, and that apparently normal platelet counts may mask the abnormal thrombopoiesis in these patients.