The Comparison of Platelet Parameters in Patients with Thrombocytopenia Associated with Acute Myeloid Leukemia and Immune Thrombocytopenia

Abstract 3317 Parameters associated with platelets (PLT) other than total PLT count, mean platelet volume (MPV), and platelet distribution width (PDW) are not widely used in clinical fields, although recent researches about them are increasingly reported. Additional platelet parameters can be helpful to evaluate the underlying cause of thrombocytopenia induced by two mechanisms-insufficient production and destruction of platelets. We investigated the significance of platelet parameters by evaluation of patients with ineffective platelet production (acute myeloid leukemia, AML) and destruction of platelets (immune thrombocytopenia, ITP). 49 adults newly diagnosed with AML (median age: 60, range: 21–86 years old) who had thrombocytopenia (<150 ×103/uL) and 47 adults with ITP (median age: 44, range: 22–82 years old) who were diagnosed with the bone marrow (BM) study were retrospectively reviewed. PLT and PLT parameters - MPV, PDW, PLT crit (PCT), mean PLT component (MPC), mean PLT mass (MPM), and large PLT count (LPLT) were measured by the ADVIA 2120 Hematology System (Siemens, USA) at the time of diagnosis. The percentage of LPLT (LPLT%) was calculated (LPLT/PLT ×100). The mean values of each group were compared using independent T-test on SPSS. The sensitivity and the specificity of each item to differentiate AML and ITP were determined by receiver operating characteristic (ROC) curve analysis. The mean values of platelet parameters of 480 male and female Korean adults in different age groups (120 in each group) who had hemoglobin level of 12–16.5 g/dl in female and 13–18.5 g/dl in male, white blood cell count of 4–10 ×103/ul, and PLT of 150–450 ×103/ul are shown in table I. The mean values of MPV, PDW, MPC, MPM, and LPLT% of ITP patients were significantly higher than those of AML (p<0.05). PLT, PCT, and LPLT did not show the difference between AML and ITP patients (Table II). Also, MPV, PDW, MPC, MPM, and LPLT% appeared significant to differentiate two diseases (p<0.05) upon ROC curve analysis (Table III). Table I. Platelet parameters in 480 Korean adults Platelet parameters Mean ¡¾ SD Total Male under 50Y Male over 50Y Female under 50Y Female over 50Y Reference range PLT (×103/¥ìl) 261 ¡¾ 53 257 ¡¾ 52 241 ¡¾ 47 259 ¡¾ 51 280 ¡¾ 59 150–450 MPV (fl) 7.9 ¡¾ 1.0 7.7 ¡¾ 0.7 7.9 ¡¾ 0.7 7.9 ¡¾ 0.7 8.0 ¡¾ 1.8 9–13 PDW (%) 51.3 ¡¾ 7.5 51.6 ¡¾ 7.5 52.1 ¡¾ 7.1 52.2 ¡¾ 5.8 49.0 ¡¾ 9.0 N PCT (%) 0.20 ¡¾ 0.04 0.20 ¡¾ 0.04 0.19 ¡¾ 0.04 0.20 ¡¾ 0.06 0.20 ¡¾ 0.04 N MPC (g/dl) 26.0 ¡¾ 1.3 26.2 ¡¾ 1.4 25.8 ¡¾ 1.3 26.4 ¡¾ 1.0 25.5 ¡¾ 1.5 N MPM (pg) 1.9 ¡¾ 0.2 1.9 ¡¾ 0.2 1.9 ¡¾ 0.2 2.0 ¡¾ 0.2 1.9 ¡¾ 0.2 N LPLT (×103/¥ìl) 4.7 ¡¾ 2.7 4.5 ¡¾ 2.7 4.6 ¡¾ 3.1 4.9 ¡¾ 2.3 4.7 ¡¾ 2.8 N LPLT% (%) 1.7 ¡¾ 0.6 1.8 ¡¾ 1.3 2.0 ¡¾ 1.4 2.0 ¡¾ 1.1 1.8 ¡¾ 1.2 N Abbreviations: SD, Standard deviation; Y, years old; N, Not determined; see text. Table II. Platelet parameters in AML and ITP patients Platelet parameters Disease Mean ¡¾ SD Reference range PLT (×103/¥ìl) AML 59 ¡¾ 35 150-450 ITP 54 ¡¾ 29 MPV* (fl) AML 9.8 ¡¾ 2.1 9–13 ITP 10.9 ¡¾ 2.8 PDW* (%) AML 53.9 ¡¾ 17.0 N ITP 60.6 ¡¾ 12.1 PCT (%) AML 0.06 ¡¾ 0.04 N ITP 0.06 ¡¾ 0.03 MPC* (g/dl) AML 22.3 ¡¾ 2.1 N ITP 25.4 ¡¾ 2.2 MPM* (pg) AML 2.0 ¡¾ 0.3 N ITP 2.4 ¡¾ 0.4 LPLT (×103/¥ìl) AML 3 ¡¾ 5 N ITP 4 ¡¾ 6 LPLT%* (%) AML 4.7 ¡¾ 5.2 N ITP 8.3 ¡¾ 9.4 Abbreviations: See table I; see text. * p<0.05. Table III. AUC for differentiation of AML and ITP with cut-off values ¡¡ AUC (95% CI) Cut-off value Sensitivity (%) Specificity (%) PLT 0.48 (0.36–0.59) 68 ×103/¥ìL 34.0 74.6 MPV* 0.66 (0.55–0.77) 10.2 fL 57.4 78.0 PDW* 0.63 (0.53–0.74) 56.3 % 66.0 69.5 PCT 0.51 (0.40–0.62) 0.07 % 40.4 72.9 MPC* 0.84 (0.78–0.92) 2.1 g/dL 87.2 76.3 MPM* 0.85 (0.75–0.91) 22.5 pg 78.7 76.3 LPLT 0.61 (0.50–0.71) 5.5 ×103/¥ìL 21.3 89.8 LPLT%* 0.67 (0.57–0.77) 4.1 % 72.3 61.0 Abbreviations: AUC, areas under the curves; CI, confidence interval; see text. * : p<0.05. In AML, deficient platelet production in the BM causes thrombocytopenia. Immune mediated destruction in the peripheral blood induces thrombocytopenia in ITP in spite of activated PLT production in BM. MPV, PDW and platelet large cell ratio (P-LCR measured by Sysmex-XE2100) had been reported to reflect production rate (MPV and PDW) and percentage of immature platelets (P-LCR) so that being higher in ITP than aplastic anemia (Kaito et al, 2004). MPV, PDW, MPC, MPM, and LPLT% were higher in ITP than AML in our study. They are also proven to differentiate AML and ITP upon ROC curve analysis. MPV, PDW, and LPLT% can be used as markers to predict the status of thrombopoiesis differentiating two mechanisms of thrombocytopenia, deficiency of production and destruction of platelets. Disclosures: No relevant conflicts of interest to declare.