Megakaryocyte- and Platelet-Derived Microparticles as Novel Diagnostic and Prognostic Biomarkers for Immune Thrombocytopenia.

Altered cell-derived microparticles (MPs) have been reported in multiple autoimmune diseases. However, the roles of megakaryocyte- and platelet-derived MPs (MKMPs and PMPs) in immune thrombocytopenia (ITP) have not been investigated. In this study, we examined plasma MKMP and PMP levels in patients with ITP and evaluated their potential diagnostic values. Plasma MKMP and PMP levels were analyzed by flow cytometry in a discovery set of ITP patients (n = 78), non-immune thrombocytopenia (TP) patients (n = 69), and age- and gender-matched healthy controls (n = 88). Samples from a therapy set of ITP patients (n = 21) were used to assess the response to thrombopoietin receptor agonist (TPO-RA) treatment. Spearman correlation analysis was performed between MP levels and disease parameters. Receiver operator characteristic (ROC) curves were generated to evaluate the diagnostic values of the MPs. We found that plasma MKMP and PMP levels were significantly lower in ITP patients than those in healthy controls (p values < 0.0001) but higher than in those in TP patients (p < 0.002 and p < 0.0002, respectively). After normalization to platelet counts, PMP/Platelet ratios in ITP patients were higher than those in TP patients and healthy controls (p values < 0.001). PMP/Platelet ratios had a diagnostic value for ITP (area under the curve = 0.808, p < 0.0001) with 73.1% sensitivity and 77.3% specificity. MKMP levels can be used to discriminate ITP from TP with a cut-off value of 112.5 MPs/µL and a sensitivity of 74.4%. Moreover, both MKMP and PMP levels were elevated in ITP patients who responded to TPO-RA treatment. Plasma PMP levels positively correlated with platelet counts in the responders (r = 0.558, p < 0.01). Our results indicate that plasma MKMP and PMP levels are decreased in ITP patients and that plasma MKMP and PMP levels may serve as biomarkers for ITP diagnosis and prediction of TPO-RA treatment response.

[The Effect of Immunized Platelet Transfusion Refractoriness on Allo-HSCT Patients with Malignant Hematological Diseases].

OBJECTIVE: To investigate the characteristics of platelet antibody in patients with hematological diseases, so as to research the effect of immunized platelet transfusion refractoriness (PTR) on the prognosis of allogeneic hematopoietic stem cell transplantation (allo-HSCT) recepients with malignant hematological diseases patients. METHODS: The clinical data of platelet antibody positive patients tested by Capture-P in the First Affiliated Hospital of Soochow University from July 1, 2014 to July 1, 2019 were retrospectively analyzed, including sex, age, disease, platelet transfusion assessments, CD34+ cells, transplant prognosis, and so on. RESULTS: In 5 years, 913 (7.28%) hematologic patients with platelet antibody positive were identified, the detection rate of females (513 cases) were higher than males (400 cases). Among the 913 patients, the antibody positive rates of 520 patients with malignant hematological diseases (acute myeloid leukemia, acute lymphoblastic leukemia and myelodysplastic syndrome) showed significantly statistical different (10.27%, 8.01%, and 7.20%) (P<0.01), and the positive rate of the acute myeloid leukemia of those patients was higher than myelodysplastic syndrome patients(α<0.0125). There were 35 cases diagnosed as immunized PTR before allo-HSCT, the platelet increments, 14 h correct count increment, progression-free survival rate and overall survival rate of those patients were significantly lower than those in negative transfusion effective patients (P<0.01), while the percentage of ABO matching was significantly higher (α<0.0125). CONCLUSION: The positive rate of platelet antibody identification is high in females and acute myeloid leukemia patients, and immunized PTR caused by antibody is a risk factor for poor prognosis of allo-HSCT in malignant hematological disease patients.

Extracellular ubiquitin levels are increased in coronary heart disease and associated with the severity of the disease.

Aim: This study aimed to evaluate concentration of plasma extracellular ubiquitin (UB) in coronary heart disease (CHD) patients and its correlation with the disease severity.Methods: Levels of UB and stromal cell-derived factor-1a (SDF-1a) were measured in 60 healthy controls and 67 CHD cases. Coronary atherosclerosis was assessed with Gensini scoring system. Spearman correlation was used to evaluate the correlation between UB and low-density lipoprotein cholesterol (LDL-C), C-reactive protein (CRP), creatine kinase-MB (CK-MB), cardiac troponin I (cTnI) or SDF-1a. The receiver-operating characteristic (ROC) curve was established to assess the predictive value of UB.Results: Plasma UB levels were significantly higher in CHD patients than in controls (p < .0001), and the levels in those with acute myocardial infarction (AMI) were higher than stable angina pectoris (SAP) and unstable angina pectoris (UAP) groups (both p < .01). UB was also positively correlated with Gensini score, CRP, CK-MB and cTnI in CHD. ROC analysis of UB showed that the area under the curve (AUC) were 0.711 (95%CI, 0.623-0.799) and 0.778 (95%CI, 0.666-0.890) for CHD and acute coronary syndrome (ACS), respectively. Plasma SDF-1a levels were elevated in CHD patients but showed no significant correlation with UB concentration or the severity of the disease.Conclusion: Plasma UB concentration was increased in CHD and the change of UB levels may reflect the progression of CHD.

[Establishment of Flow Cytometric Immunobead Array Assay for Quantitation of Platelet-Specific Antibodies and Its Application].

OBJECTIVE: To establish a flow cytometric immunobead array assay (FCIA) to quantify platelet antibodies and to explore its application in the diagnosis and treatment of ITP. METHODS: The guantitative standard curve was established by binding the human IgG of known concentration on antibody-coated microbeads; at the same time, the platelet-specific antigen and antibody complex was captured and levels of platelet antibodies were detected using the microbeads coated by 5 kinds of antibodies against platelets suca as GPIX (SZ1), GPⅠb (SZ2), GpⅢa (SZ21), GPⅡb (SZ22) and p-selection (SZ51). The fluorescence signal detected by flow cytometry were transformed into the conentration of platelet antibodies in samples through the quantitative standard curve, thereby establishing the method for quantititive detection of platelet-specific antibodies in plasm samples (FCIA), moreover the property, efficiency and clinical application of establishod FCIA method were evaluated. RESULTS: The FCIA could detect 5 kinds of antibodies against GPIX, GPⅠb, GpⅢa, GPⅡb and ß-selection within a broad range of 33.29-1280 ng/ml, 45.17-1280 ng/ml, 42.07-1280 ng/ml, 46.40-1280 ng/ml, 42.48-1280 ng/ml and 42.48-1280 ng/ml respectively, and their recovery rates were 115.23%, 112.58%, 117.47%, 107.64% and 112.67% respectively. The intra-assay coefficient of variation (CV) for anti- GPIX, -GPⅠb, -GpⅢa, -GPⅡb and p-selection antibodies was 3.54%, 3.63%, 4.66%, 6.43% and 6.67% respectively, and the inter-assay CV for above mentioned antibodies were 10.89%, 7.57%, 10.34%, 6.95% and 10.72% respectively. The detection showed that the levels of 5 kinds of platelet-specific antibodies in ITP group all were higher than those in non-ITP and healthy control groups (P＜0.01). The sensitivity, specificity and accuracy of quantitatively detecting 5 kinds of antibodies for diagnosis of ITP by FCIA were 68.29%, 84.98% and 78.95% respectively, while the sensitivity, specificity and accuracy of detecting 5 kinds of antibodies by modified indirect MAIPA were 41.46%, 90.41% and 72.81% respectively. CONCLUSION: The established quantitative FCIA for detection of antibodies provides a powerful tool for diaghosis and evaluation of therapeutic efficacy and prognosis of ITP patients.

Flow cytometric immunobead assay for quantitative detection of platelet autoantibodies in immune thrombocytopenia patients.

BACKGROUND: Platelet autoantibody detection is critical for immune thrombocytopenia (ITP) diagnosis and prognosis. Therefore, we aimed to establish a quantitative flow cytometric immunobead assay (FCIA) for ITP platelet autoantibodies evaluation. METHODS: Capture microbeads coupled with anti-GPIX, -GPIb, -GPIIb, -GPIIIa and P-selectin antibodies were used to bind the platelet-bound autoantibodies complex generated from plasma samples of 250 ITP patients, 163 non-ITP patients and 243 healthy controls, a fluorescein isothiocyanate (FITC)-conjugated secondary antibody was the detector reagent and mean fluorescence intensity (MFI) signals were recorded by flow cytometry. Intra- and inter-assay variations of the quantitative FCIA assay were assessed. Comparisons of the specificity, sensitivity and accuracy between quantitative and qualitative FCIA or monoclonal antibody immobilization of platelet antigen (MAIPA) assay were performed. Finally, treatment process was monitored by our quantitative FCIA in 8 newly diagnosed ITPs. RESULTS: The coefficient of variations (CV) of the quantitative FCIA assay were respectively 9.4, 3.8, 5.4, 5.1 and 5.8% for anti-GPIX, -GPIb, -GPIIIa, -GPIIb and -P-selectin autoantibodies. Elevated levels of autoantibodies against platelet glycoproteins GPIX, GPIb, GPIIIa, GPIIb and P-selectin were detected by our quantitative FCIA in ITP patients compared to non-ITP patients or healthy controls. The sensitivity, specificity and accuracy of our quantitative assay were respectively 73.13, 81.98 and 78.65% when combining all 5 autoantibodies, while the sensitivity, specificity and accuracy of MAIPA assay were respectively 41.46, 90.41 and 72.81%. CONCLUSIONS: A quantitative FCIA assay was established. Reduced levels of platelet autoantibodies could be confirmed by our quantitative FCIA in ITP patients after corticosteroid treatment. Our quantitative assay is not only good for ITP diagnosis but also for ITP treatment monitoring.

Plasma microRNAs characterising patients with immune thrombocytopenic purpura.

Altered microRNA (miRNA) expression has been reported in patients with immune thrombocytopenic purpura (ITP). However, the detailed expression profiling of cell-free circulating miRNAs in ITP patients has not been fully investigated. In this study, we aimed to examine plasma miRNAs in ITP patients and evaluate their diagnostic values. Plasma samples from 74 ITP patients and 58 healthy controls were obtained and allocated into discovery, validation, and therapy-response sets. Initial screen with a miRNA microarray assay identified 23 miRNAs with different levels between ITP patients and healthy controls (>1.5-fold changes; p<0.01). Subsequent quantitative real-time PCR confirmed eight up-regulated miRNAs (miR-320c, miR-642b-3p, miR-1275, miR-3141, miR-4270, miR-4499, miR-4739 and miR-6126) and three down-regulated miRNAs (miR-144-3p, miR-1281 and miR-3162-3p) in ITP patients. The levels of these circulating miRNAs varied, depending on ITP subtypes, i.e. newly-diagnosed, persistent and chronic ITP, and between treatment responders and non-responders. In receiver operator characteristic analysis, 10 miRNAs had positive diagnostic values (p<0.05) when tested individually. The diagnostic value improved when the miRNAs were analysed as a panel or together with the analysis of anti-platelet autoantibodies. Plasma miR-3162-3p levels were also found to positively correlate with platelet counts in ITP patients (r=0.338, p=0.01). Our results indicate that plasma miRNA profiles are altered in ITP patients and that the differentially expressed miRNAs may be used as biomarkers to improve the diagnosis of ITP.