Lower platelet count with increased density of platelet antigens in granulocyte colony-stimulating factor mobilized peripheral blood stem cell donors.

BACKGROUND/PURPOSE: Granulocyte colony-stimulating factor (G-CSF) is widely used for prophylaxis and treatment of neutropenia in cancer patients and also for peripheral blood stem cells (PBSC) mobilization. The aim of this study is to evaluate the possible changes of platelet surface antigens after G-CSF injection in PBSC donors compared with healthy control. METHODS: Between January 1st and December 31st, 2014, 48 healthy voluntary PBSC donors were eligible for this study. Donors received G-CSF (Filgrastim) subcutaneously for five days, and then their whole blood was collected for complete blood count. Analysis of platelet antigens was performed by flow cytometry. Sixteen healthy controls were also included for comparison. RESULTS: Lower platelet counts were found in PBSC donors after G-CSF use and in comparison with health controls. The platelet size evaluated by forward scattering (FSC) showed smaller platelets in PBSC donors after G-CSF use compared with healthy controls (39.3 vs 46.7 mean fluorescence intensity, P = 0.015). CD31 were higher in PBSC donor (203.2 vs. 120.7, P < 0.001). Except CD31, other platelet surface antigens were not different between PBSC donors and healthy controls. After adjusting by FSC data, the mean antigen intensity/FSC of CD31, CD41a, CD42a, CD42b and CD61 showed 5.45 vs 2.78 (P < 0.001), 4.35 vs 3.47 (P = 0.007), 3.87 vs 3.17 (P = 0.015), 20.45 vs 16.94 (P = 0.045), and 5.98 vs 4.88 (P = 0.018) respectively. CONCLUSION: We noted higher density of platelet surface antigens, lower platelet count and smaller platelet size after G-CSF injection.

Abnormal platelet immunophenotypes and percentage of giant platelets in myelodysplastic syndrome: A pilot study.

OBJECTIVES: Myelodysplastic syndrome (MDS) is a heterogeneous hematopoietic stem cell disorder with thrombocytopenia. Flow cytometric immunophenotyping of blood cells has been instrumental in diagnosis as co-criteria, but the data regarding platelets remains lacking. This study aims to determine if there is a difference in surface antigen levels on platelets by comparing surface antigen levels in MDS patients and healthy control subjects. Concurrently, as flow cytometric gating can reveal the diameter of cells, this study will investigate differences in giant platelet percentage by comparing these percentages in high- and low-risk MDS patients. STUDY DESIGN: Twenty newly diagnosed MDS patients were enrolled in this study. Platelet surface antigen levels were determined by measuring the binding capacity of antibodies with flow cytometry. RESULTS: Platelets of MDS patients were shown to have a lower level of CD61 and higher levels of CD31 and CD36 than healthy controls. Judged by forward scatter (FSC), MDS patients' platelets appeared to be larger than those of healthy control subjects, whereas the MFI adjusted by diameter (MFI/FSC ratio) of CD31, CD41a, CD42a, CD42b and CD61 on platelets were lower in MDS patients than in healthy control subjects. There was a significant quantity of giant platelets found in MDS patients, and the high-risk MDS patients tended to have a higher percentage of giant platelets than low-risk patients. Conclusions: All the results indicate that MDS patients exhibit a lower antigen presentation (MFI) adjusted by diameter on platelets than healthy controls and the giant platelets detected by flow cytometry might correlate with the condition of MDS.

Higher CD56+ or CD2+ lymphocyte percentage predicts poor steroid response in patients with immune thrombocytopenia.

INTRODUCTION: Immune thrombocytopenia (ITP) is known as an immune-mediated disease and often evolves to chronic type in adult. Corticosteroids only work in around 60% of patients. This study evaluated the roles of subgroup lymphocytes from peripheral blood in ITP adults with different treatment response. METHODS: Between October 2009 and March 2017, 37 adults were newly diagnosed as ITP requiring treatment. The patients were separated into two groups: 23 patients with platelet count <50,000/µL with corticosteroid dependence or second-line treatment (Poor-responder Group), and 14 patients with platelet counts <50,000/µL with standard steroid treatment, which stopped within three months (Good-responder Group). Subgroup lymphocyte percentages of peripheral blood were determined through flow cytometry before treatment. Data analysis with Mann-Whitney test and receiver operating characteristic curves were performed using GraphPad Prism (Version 7). A p-value of <0.05 was considered significant. RESULTS: Lymphocyte percentage was significantly lower in Poor-responder Group than in Good-responder Group (p = 0.008). In subgroup lymphocytes, higher percentages of CD19+ B lymphocytes were found in Good-responder Group (p = 0.03). In Poor-responder Group, a higher CD2+ and CD56+ lymphocytes were observed (p = 0.02 and 0.03). By the cut-off value of percentage of CD56+ lymphocytes with 24.5% or CD2+ lymphocytes with 85.7%, the specificity showed 92.86%. CONCLUSIONS: This study found that newly diagnosed ITP patients with increased percentages of CD56+ or CD2+ lymphocytes in peripheral blood associated with a poorer response to steroid treatment.