“Study of JAK2 V617F mutation, serum B12 level and interleukin – 23 level in polycythemia vera

Introduction: Myeloproliferative neoplasms (MPNs) including Polycythemia Vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are clonal hematopoietic stem cell disorders which originate from a single stem cell. Usually one cell line predominates in a given disorder. Over the last 12 years, several somatic mutations have been described in MPN classification like: JAK2, CALR and MPL, but JAK2 is the most frequent, with frequencies of approximately 98% in PV, 50% to 60% in ET, and 55% to 65% in PMF. It is believed that cytokines participate in the activation of JAK2V617F, one of them IL-23 that acts as a pro-inflammatory mediator and can induce chronic inflammation and its plasma level increased in MPN patients. High serum cobalamin is frequently observed in malignant blood diseases and MPDs. An elevated level of plasma cobalamin is found in 30 to 50% of patients with Polycythemia Vera (PV). Objectives: the study aimed to: 1. Estimate JAK2 V617F mutation gene PV in Iraqi patients. 2. Measure the levels of IL-23 and B12 in the PV cases with JAK2V617F +ve mutation. Patients and Methods: Thirty patients were diagnosed as polycythaemia according to their clinical and laboratory findings like: CBC, and bone marrow biopsy (for some patients), liver and renal function test, abdominal U/S some with CT abdomen and JAK2 V617F mutation. Then levels of B12 and IL-23 were measured and correlated with CBC results. Results and Discussion: The mean age of PV patients was (52.0  12.5) with a range of (22-71 yrs), there was a PV case in a 22 years old male which was considered as a rare condition also male to female ratio of (1:1) is unusual. Splenomegaly and hepatomegaly present in 36.7% and 13.3% of PV patients respectively. The mean Hb was (17.2 1.7 g/dl), while the mean WBC count was (12.3±3.9 x109/L) and the platelet count was (446.0±285.2). Plasma levels of IL-23 were significantly increased in all patients with JAK2 V617F +ve mutation PV with mean (70.00±72.18 pg/mL) and range (8.5-259.0) and there was a significant positive correlation between IL-23 level and the total WBC count. B12 serum level was high in 16 of total 30 cases, with mean serum level (766.54±583.95pg/mL) .There was no Correlation between B12 level and Hb level, Platelet count and WBC count. Also there was no correlation between IL-23 and B12. Conclusions: 1. Study of JAK2V617F mutation is an important test in MPN patients, particularly in those who suspected to have PV. 2. The diagnosis of PV was based on clinical, haematological and genetic tests. While B.M. biopsy was not performed for the studied cases, it is recommended by WHO as a major criterion to establish a diagnosis of PV. (WHO criteria for PV diagnosis, 2016) 3. High levels of IL-23 in the sera of all PV patients that positively correlate with WBC count. 4. Cobalamin levels was elevated in 53.3% of PV.