Evaluation of the level of bone marrow fibrosis in patients diagnosed with essential thrombocytosis and polycyctemia vera with LDH level and JAK/2 gene mutation, CALR mutation and MPL mutation

Myeloproliferative diseases (MPH) are among the hematological diseases that have been waiting for treatment in hematology since ancient times and are frequently seen in the community. Polycythemia vera (PV) and essential thrombocytosis (ET), subgroups of myeloproliferative disease (MPH), are the most common. Despite all the advances in medicine, the factors that play a role in the etiology and progression of MPHs are still not fully elucidated. In these patients, besides thromboembolism and leukemic transformation, bone marrow fibrosis can also be seen during the disease process. Currently, the only way to definitively demonstrate the presence of bone marrow fibrosis is a bone marrow biopsy. Findings such as splenomegaly, tear cells on peripheral smear and leukoerythroblastosis are only seen in cases of advanced fibrosis. In this study, we examined whether there is a relationship between lactate dehydrogenase level and bone marrow fibrosis of JAK2, CALR, MPL gene mutations which is used in the diagnosis and follow-up of patients with ET and PV. The aim of our study was to shed light on the lactate dehydrogenase level and JAK2, CALR, MPL gene mutations possibility of the occurrence of bone marrow fibrosis. Patients who were diagnosed and followed up in the Hematology clinic of Fırat University Medical Faculty Hospital since 2010 were included in the study. Patients diagnosed with ET and PV according to WHO 2008 criteria were included in our study. A total of 154 patients, 62 of whom were diagnosed with PV and 92 with a diagnosis of ET, were included in the study. Demographic data of the patients were evaluated. Bone marrow biopsy specimens were evaluated according to the European Council's bone marrow fibrosis staging. The presence of reticulin and massontrichrome (MTC) was used as a bone marrow fibrosis marker. LDH levels of the patients at the time of bone marrow biopsy were recorded retrospectively. In our study, when the relationship between JAK2 positivity and bone marrow fibrosis in 62 patients with PV was examined, no statistically significant difference was found (reticulin (p=0.160), MTC (p=0.186)). When the relationship between JAK2 positivity and bone marrow fibrosis in 92 patients with ET in our study was examined, no statistically significant difference was found (reticulin (p=0.522), MTC (p=0.663)). In our study, when the relationship between LDH level and bone marrow fibrosis in 62 patients with PV was examined, no statistically significant difference was found (reticulin (p=0,276), MTC (p=0,076). When the relationship between LDH level and bone marrow fibrosis in 92 patients with ET in our study was examined, no statistically significant difference was found (reticulin (p=0,618), MTC (p=0,084). A positive and significant correlation was observed between LDH level and bone marrow fibrosis grade in 62 patients with PV in our study (p<0.001). When only ET patients were evaluated, no correlation was observed. The relationship the percentage of JAK2 gene mutations and the degree of bone marrow fibrosis in patients with ET and PV was examined, no significant difference was observed. In conclusion, in our study, which included patients diagnosed with PV and ET who were diagnosed and followed up in our center, a positive and significant correlation was found between LDH level and bone marrow fibrosis grade in patients with PV. This shows that LDH may be a guide for the bone fibrosis grade of PV patients. Although it is known that LDH increases in myeloproliferative diseases and JAK2 gene mutation positivity is known, there are not many studies evaluating their effects on prognosis and clinic. In order to elucidate this situation, studies in more than one center, in larger groups and in which more parameters are examined are needed. Keywords: Myeloproliferative diseases, JAK2, LDH, CALR, MPLbone marrow fibrosis