Comparison of Mean Platelet Component and Mean Platelet Mass in an Individual during Hyperproductive and Hypoproductive Thrombocytopenic States

Introduction

The Siemens ADVIA 120 has the capacity to calculate the mean platelet (PLT) component (MPC), a measure of PLT density, and the mean PLT mass (MPM). Jin Kim and colleagues (Blood Coag Fibrinol 2014) studied these parameters in 480 controls (CTRL), in 44 patients with immune thrombocytopenia (ITP), and in 57 patients with acute myelogenous leukemia (AML). Their results showed CTRL: Mean PLT 259 ± 54 x10³/µL, Mean MPC 26.0 ± 1.3 gm/dL, Mean MPM 1.9 ± 0.2 pg; ITP: Mean PLT 48 ± 22 (x10³/µL), Mean MPC 25.3 ± 2.1 gm/dL, Mean MPM 2.4 ± 0.4; AML Mean PLT 45 ± 22 (x10³/µL), Mean MPC 22.1 ± 2.1 gm/dL, Mean MPM 2.0 ± 0.3 pg, p < 0.01.Overall, MPC and MPM were significantly higher in ITP than in AML.

We replicated their findings (Melinscak J Thromb Haemost 2015;13Suppl2:607a) in 10 CTRL: Mean PLT 261 ± 55 x10³/µL, Mean MPC 28.1 +/- 0.7 gm/dL Mean MPM 1.9 +/- 0.1 pg; in 20 patients with ITP: Mean PLT 64 ± 46 x10³/µL Mean MPC 26.7 ± 1.9 gm/dL, Mean MPM 2.4 ± 0.5 pg; and in 20 patients with hypoproductive thrombocytopenias (HYP): Mean PLT 54 ± 40 x10³/µL, Mean MPC 24.2 ± 1.9 gm/dL, Mean MPM 2.0 ± 0.2 pg, p < 0.01.

We now report on these parameters in an individual who had ITP and chemotherapy-induced thrombocytopenia (CIT) at different time-points.

A 58-year-old man with no past medical history presented to the emergency room in 04/2007 with epistaxis and hematuria. His complete blood counts were white blood count 9700/µL, hemoglobin 15.2 g/dL, hematocrit 41.5%, and PLT 7000/µL. He was diagnosed with ITP. His ITP was refractory to dexamethasone, anti-Rh(D), and danazol. It responded to the combination of methylprednisolone, rituximab, and vincristine. A relapse in 2007 responded to a single dose of rituximab while a relapse in 2008 responded to rituximab and vincristine. Relapses in 2011 and 2013 were treated with dexamethasone 40 mg daily for 4 days and rituximab 375 mg/m2 weekly for 4 weeks. A relapse in 05/2014, with PLT 17,000/ul, was treated with rituximab 375 mg/m2 weekly for 4 weeks. His PLT rose to 106,000/ul in 11/2014. In 12/2014, he developed a nasopharyngeal mass leading to nasal congestion and dyspnea. He was diagnosed with high grade B cell lymphoma. Following debulking therapy with rituximab, cyclophosphamide, and prednisone in 01/2015, he received 6 cycles DA-REPOCH from 02/2015 through 05/2015. PLT was 160,000/uL prior to the start of DA-REPOCH, nadired at 10 days at 91,000/ul, and normalized at 3 weeks at 262,000/ul. Similar trends occurred with subsequent cycles. The magnitude of nadir was progressive; following the 6^th chemotherapy cycle, the nadir PLT was 34,000/ul. MPC and MPM were measured in 2013 and in 2014 on five different dates while he had active ITP and in 2015 on three different dates while he had CIT.

His results showed respectively during ITP vs CIT: mean PLT 79,800/µL ± 33,100/µL vs 69,000/µL ± 32,400/µL, p=0.67; mean MPC 28.8 ± 0.876 gm/dL vs 26.2 ± 1.50 gm/dL, p=0.02; mean MPM 2.77 ± 0.305 pg vs 2.24 ± 0.114 pg, p=0.03. Overall, MPC and MPM were significantly higher during ITP than during CIT.

This case is unique since both a hyperproductive and a hypoproductive state occurred, at different time-points, in the same individual. The values for the MPC and MPM in this study were consistent with those in prior reports of ITP and HYP. A strength of this study is that the MPC and MPM assays were measured within 2 hours of collection. The MPC sharply decreases when studied 4 to 6 hours after collection. The significant difference in MPC and MPM during these diverse thrombocytopenic states attests to the clinical utility of these parameters in distinguishing ITP from HYP.

No relevant conflicts of interest to declare.