RESUMO
Objective To explore the method for early diagnosis of masked polycythemia vera (mPV) by comparing and analyzing the features of mPV and polycythemia vera (PV). Methods A total of 200 newly diagnosed male patients were collected based on diagnostic criteria, including 100 cases of PV and 100 cases of mPV. Erythropoietin (EPO), neutrophil alkaline phosphatase (NAP) score, bone marrow biopsy (BMB), and JAK2 V617F mutation were evaluated in all cases. After 6 months, hemoglobin (Hb) and JAK2 V617F mutation load were detected in patients without special treatment in two groups during follow-up. Results EPO, NAP score, BMB hematopoietic volume and the number of megakaryocyte had no statistical differences between PV group and mPV group [(3.4 ± 0.7) U/ml vs. (3.2±0.6) U/ml, (276±20) score vs. (278±21) score, (78±10) % vs. (76±9) %, (53±6) vs. (51±5), respectively], while JAK2 V617F mutation load in PV group was higher than that in mPV group[(89.2±9.4) % vs. (78.1±8.6) %, P<0.05]. In mPV patients without special treatment, Hb ≥185 g/L was found in 37 patients after 6 months, and the level of Hb and JAK2 V617F mutation load in these 37 patients reached (194±8) g/L and (90.7±9.1) %, respectively. Conclusions There is no significant difference in EPO, NAP score and BMB between PV and mPV, but the JAK2 V617F mutation load is different. In mPV patients without special treatment, Hb level can reach the typical PV diagnostic criteria after 6 months, meanwhile, JAK2 V617F mutation load is also increased.