The Association Between Platelet Reactivity and Bleeding Risk in Adult ITP

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

UNKNOWN

Total Enrollment

400 participants

Study Classification

OBSERVATIONAL

Study Start Date

2017-12-01

Study Completion Date

2018-12-31

Brief Summary

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It seems reasonable to assume that patients who present significant bleeding symptoms may have different quality of platelets than those without bleeding. This question was addressed in a study that examined platelet function in adult ITP patients, which try to determine whether this correlated with bleeding risk. Previous reports have suggested that measuring platelet function may help define patients at highest risk of bleeding. In addition, Middelburg and colleagues corrected platelet function for quartile of platelet count, using \<32×10\^9/L as the lowest cohort and \>132×10\^9/L as the top quartile. They demonstrated that increased platelet reactivity (as measured by flow cytometry) was associated with decreased risk of bleeding but particularly for those patients with the lowest platelet counts. Further studies in a larger cohort are needed to confirm this correlation. Our study aimed at standardizing a prediction model to evaluate the bleeding risk of adult ITP patients with the use of platelet function tests.

Detailed Description

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The investigators are undertaking a prospective multicenter double-blind study of 400 adult patients with immune thrombocytopenia from 6 medical centers in China. We adopted three different assays that examined platelet function and reactivity. 1) Flow cytometry: Citrate anticoagulated whole blood was diluted in PBS to result in 20×10\^9/L platelets, and 20 μl was aliquoted into polystyrene test tubes. Ten microliters of anti-CD42b-PE was added and incubated at room temperature for 10 min. Agonists (TRAP-6 12.5 μMol/L, Collagen 20 μg/mL, ADP 2 μM, Epinephrin 20 μM, Arachidonic acid 0.275 mM, Ristocetin 1.5 mg/mL) or PBS were added (10 μl each) and incubated again for 10 min. Then mAb PAC-1-FITC or anti-CD62p-FITC (10 μl each) or the corresponding isotype-matched controls were added. After 15-min incubation in the dark, the reaction was stopped with 500 μl PBS. Samples were analyzed on a flow cytometer (FACScan, Becton-Dickinson) by measuring 10,000 events in the CD42b-positive fraction. 2) Filopodia quantification: Briefly, platelets in Tyrode's buffer were allowed to adhere to VWF (9×10\^6 cells/coverslip) in the presence of botrocetin (1 μg/mL) and Integrilin (40 μg/mL) at 37°C. After 15 min, non-adherent platelets were removed by washing and adherent platelets were fixed with 4% PFA, stained with TRITC-phalloidin (2 μg/mL) and viewed by epifluorescence microscopy for filopodia count. 3) Platelet aggregation: Measured on an automated platelet aggregation analyzer.

Understanding bleeding risk and underlying determinants of bleeding is important in order to help recognize patients that will require pharmacologic therapy even at higher platelet counts. Previous studies have suggested that low platelet counts, increased patient age, use of concurrent medications, and male sex are associated with increased bleeding risk. The present investigation will answer whether platelet function predicts the severity of bleeding in adult ITP patients. Clinical information of recruited participants includes gender, age, platelet count and physical/laboratory examination. Blinding was set between investigators who evaluated bleeding risks and those who performed experiments.

Conditions

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Immune Thrombocytopenia

Keywords

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Platelet function Bleeding risk Immune Thrombocytopenia

Study Design

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Observational Model Type

COHORT

Study Time Perspective

PROSPECTIVE

1. Untreated adult ITP patients of both genders between the ages of 18 and 80 years.
2. Participants of either acute or chronic phase; with or without thrombocytopenia; with or without bleeding manifestation.

Exclusion Criteria

1. Received high-dose steroids or IVIG within 3 weeks prior to the test.
2. Received second-line ITP-specific treatments (eg, cyclophosphamide, 6-mercaptopurine, vincristine, vinblastine, etc) within 3 months prior to the test.
3. Current HIV infection, hepatitis B virus or hepatitis C virus infections.
4. Severe medical condition (liver and kidney function impairment).

Minimum Eligible Age

18 Years

Maximum Eligible Age

80 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Responsible Party

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Ming Hou

Professor and Director

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Jun Peng, MD, PhD

Role: STUDY_DIRECTOR

Qilu Hospital, Shandong University

Locations

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Qilu Hospital, Shandong University

Jinan, Shandong, China

Site Status RECRUITING

Countries

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China

Central Contacts

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Ming Hou Hou, MD, PhD

Role: CONTACT

Phone: 86-531-82169879

Email: [email protected]

Review additional registry numbers or institutional identifiers associated with this trial.

Plt function and bleeding risk

Identifier Type: -

Identifier Source: org_study_id

The Association Between Platelet Reactivity and Bleeding Risk in Adult ITP

Study Results

Basic Information

Brief Summary

Detailed Description

Conditions

Keywords

Study Design

Study Groups

Group A

Platelet function tests

Group B

Platelet function tests

Group C

Platelet function tests

Interventions

Platelet function tests

Eligibility Criteria

Inclusion Criteria

Exclusion Criteria

Sponsors

Traditional Chinese Medicine Hospital Affiliated to Shandong University

Jinan Central Hospital

Qianfoshan Hospital

Shandong Provincial Hospital

Shandong University Second Hospital

Shandong University

Responsible Party

Ming Hou

Principal Investigators

Jun Peng, MD, PhD

Locations

Qilu Hospital, Shandong University

Countries

Central Contacts

Ming Hou Hou, MD, PhD

References

Khellaf M, Michel M, Schaeffer A, Bierling P, Godeau B. Assessment of a therapeutic strategy for adults with severe autoimmune thrombocytopenic purpura based on a bleeding score rather than platelet count. Haematologica. 2005 Jun;90(6):829-32.

Middelburg RA, Roest M, Ham J, Coccoris M, Zwaginga JJ, van der Meer PF. Flow cytometric assessment of agonist-induced P-selectin expression as a measure of platelet quality in stored platelet concentrates. Transfusion. 2013 Aug;53(8):1780-7. doi: 10.1111/trf.12001. Epub 2012 Dec 7.

Middelburg RA, Carbaat-Ham JC, Hesam H, Ragusi MA, Zwaginga JJ. Platelet function in adult ITP patients can be either increased or decreased, compared to healthy controls, and is associated with bleeding risk. Hematology. 2016 Oct;21(9):549-51. doi: 10.1080/10245332.2016.1180097. Epub 2016 May 9.

Panzer S, Hocker L, Koren D. Agonists-induced platelet activation varies considerably in healthy male individuals: studies by flow cytometry. Ann Hematol. 2006 Feb;85(2):121-5. doi: 10.1007/s00277-005-0029-5. Epub 2005 Nov 10.

Panzer S, Rieger M, Vormittag R, Eichelberger B, Dunkler D, Pabinger I. Platelet function to estimate the bleeding risk in autoimmune thrombocytopenia. Eur J Clin Invest. 2007 Oct;37(10):814-9. doi: 10.1111/j.1365-2362.2007.01855.x. Epub 2007 Aug 28.

Other Identifiers

Plt function and bleeding risk