Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as new possible minor criteria for diagnosis of polycythemia vera

Introduction: The role of inflammation in the pathophysiology of polycythemia vera (PV) is important. The presence of JAK2 mutations is important in the diagnosis of PV, and serum levels of erythropoietin (EPO) also play a supporting role. However, serum EPO levels show some limitations. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are a readily available marker of inflammation. Thus, we examined whether NLR & PLR might diagnose PV in erythrocytosis patients. We compared NLR & PLR and EPO diagnostic values.

Methods: We retrospectively reviewed clinical and laboratory data from two referral hospitals. Two hundred and eighty-five patients with erythrocytosis who underwent a test for the JAK2 mutation were included. It wac classified as the PV group and the secondary polycythemia (SP) group.

Results: The median NLR & PLR in the PV group (n = 70) was significantly higher than that in the SP group (n = 170) (NLR: 6.04 vs. 1.77, PLR: 283.18 vs. 101.56, respectively, p < 0.001). In the receiver operating characteristic analysis, the area under the curve of NLR & PLR was significantly higher than that of serum EPO (NLR vs EPO: 0.921 vs. 0.827, p = 0.003; PLR vs EPO: 0.917 vs 0.827, p = 0.003).

Conclusion: In conclusion, NLR & PLR were higher in PV than in SP and showed better diagnostic value than serum EPO level, highlighting their potential as minor diagnostic criteria in patients with PV.