The Philadelphia-negative classical chronic myeloproliferative neoplasms are characterized by proliferation of one or more cell lines in the bone marrow and increased number of mature and immature cells in the peripheral blood. These myeloproliferative neoplasms include; polycythemia vera, essential thrombocythemia and idiopathic myelofibrosis, in which JAK2V617F is by far the most prevalent mutation. Because of the rapid turnover of cells in these neoplasms, derangement in the serum levels of vitamin B12 and folate is expected.
To assess the possible correlation of serum B12 and folate levels with JAK2V617F mutation in patients with polycythemia vera, essential thrombocythemia and idiopathic myelofibrosis.
PATIENTS AND METHODS:
This case-control study was conducted from December 2012 to December 2013, and enrolled 54 patients, diagnosed as polycythemia vera (36), essential thrombocythemia (6) and idiopathic myelofibrosis (12), attending Medical City, Baghdad Teaching Hospital. Twenty healthy volunteers were included as a control group. JAK2V617F mutation status had been reviewed at time of sampling. The following investigations were done: automated complete blood counts; serum B12 and folate were measured using the electrochemiluminescence immunoassay.
The mean levels of serum B12 and folate were much higher in myeloproliferative neoplasm patients than control group (p-value of 0.028 and 0.004 respectively).
Serum B12 level showed significant difference between polycythemia vera patients with positive JAK2V617F and negative mutation (p= 0.04), while no significant difference was found for serum folate level (p= 0.630). Insignificant differences were also found for idiopathic myelofibrosis patients (B12, p= 0.140; and serum folate, p= 0.098), and essential thrombocythemia patients (B12, p= 0.133; and serum folate, p= 0.800).
Correlations of serum folate and B12 with hematocrit, white blood cell count, absolute neutrophil count, platelet count, mean cell volume, and mean cell hemoglobin in myeloproliferative neoplasm patients: significant correlations were only found in PV patients between B12 and total white blood cell count, absolute neutrophil count and platelet count (p= 0.009, 0.012 and 0.002 respectively).
There is derangement in the levels of serum B12 in patients with polycythemia vera in relation to JAK2V617F mutation, thus we may propose that this mutation may have a possible impact on polycythemia vera patients, in particular, reflected by higher levels of serum B12 through the associated increase in absolute neutrophil count.