JAK 2 NEGATIVE POLYCYTHEMIA VERA IN A TERTIARY CARE CENTER IN WEST UP POPULATION IN INDIA :A RARE PRESENTATION OF 5 CASES
Authors:   Assistant Professor, School of Medical Sciences and Research,Sharda University., Tiwari Neema , Chaturvedi Nidhi ,   Assistant Professor, Pathology(hematology), Subharti Medical College, Meerut., Bansal Rani ,   Professor and Head of the Department of Pathology, Subharti Medical College, Meerut.
Published: March 2023

Introduction: Polycythaemia vera (PV) belongs to the group of myeloproliferative neoplasms with an excessive increase in hemoglobin levels.(1). It has been seen that JAK2 V617F mutation present in 80-90% of MPNs and JAK2 exon12 mutations are seen in 4%-5% cases of MPNs like PV.As per an Indian data the JAK2V617F mutational frequency in Indian population was 81.8% for PV, which was different from that reported in western literature as more than 95% for PV.Activation of JAK2 by either point mutation or fusion protein causes activation of the JAK-STAT pathway. While mutations in JAK2 are reported in numerous MPN phenotypes, exon 12 mutations specifically result in erythrocytosis due to increased EPO signalling. In India, the incidence of JAK2-negative polycythemia is relatively high, reaching up to 18%. (2,3) Case series: Case 1-A 21-year male presented to the hematology OPD with complains of paresthesias and off and on headache for the past 6 months. He was on multiple symptomatic medications but to no relief. On routine investigations it was seen that he had a persistent hemoglobin level fluctuating between 17.5gm/dl and 18.5 gm/dl. He has iron deficiency for which he is on single oral iron tablet. No definite organomegaly was seen. In hematology OPD he was investigated for polycythemia vera keeping in mind the WHO criterias.His Serum EPO levels are within normal range,JAK2 V617F/exon 12mutation analysis is negative.A bone marrow aspiration and biopsy study done shows Hypoplastic marrow for age with erythroid predominance. In view of clinical suspicion of JAK 2 negative PV he is being treated with ecosprin, phlebotomy every 3 months and supplemental iron orally. The patient is clinically relieved of his symptoms of peripheral neuropathy. His last hemoglobin value is stable at 16.5gm/dl.Case 2-A 32 -year male presented to hematology OPD with mild headache and weakness for 6 months. A routine CBC investigation showed a high hemoglobin level of 18.4 gm/dl. Mildly raised RBC count was also seen. A subnormal serum EPO levels of 3.7 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon 12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved.Case 3- A 29-year male presented to hematology OPD with paresthesias and weakness for 3 months. A routine CBC investigation showed a high hemoglobin level of 19.7 gm/dl. Mildly raised RBC count was also seen. Rest all parameters were within normal limits. On examination no hepatosplenomegaly or lymphadenopathy was seen. A low serum EPO levels of <1 mIU/Ml (4.3-29.0 mIU/ML) was seen. JAK 2V617F/exon12 mutation analysis was negative. The patient has been started on ecosprin and phlebotomy every 3 months and is symptomatically relieved. Case4-33 year male presented to OPD with fatigue and paresthesias.CBC showed increased hemoglobin of 18gm/dl.Patient was a non-smoker.Vitamin B12 was>1000gm/dl.Bone marrow showed mildly predominant myeloid series.JAK2 mutation profile was negative but the patient responded to phlebotomy.Case5:A 28 year female had recurrent headaches however MRI and other investigations were normal. A serum EPO level done on suspicion of PV showed subnormal ranges.Bone marrow was reported as reactive.JAK2 mutation analysis was negative however patient responds to ecosprin and hyroxyurea. Conclusion-All five cases that presented to the department had been undiagnosed before they reached our setup. The unique feature of all these cases was negativity for both JAK2V617F as well as JAK2 exon 12 mutation despite its clinical behaviour being that of PV .These cases are being actively managed as low risk polycythemia vera and since the start of the treatment comprising of phlebotomy once every 3 months their hemoglobin and hematocrit concentrations are maintained.No cytoreductive therapy is being given .Such unique presentations need to be reported and discussed extensively.