ThrombocytopeniaNCT00015639
Identification of Donors of CD36-Deficient Platelets Among Japanese Individuals on the NIH Campus
An observational study of Thrombocytopenia, run by National Institutes of Health Clinical Center (CC) at 1 site in United States.
Trial summary
Plasma histidine-rich glycoprotein (HRG) binds to platelets in the presence of zinc (1). This binding is totally blocked by a monoclonal antibody directed against platelet membrane CD36. Therefore, CD36 is assumed to carry the platelet binding site for HRG (2). Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Thrombocytopenia
- How many people
- 150 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2001to Feb 2004
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Phase I:
- Full Japanese, African American, and Taiwanese ancestry
- At least 18 years of age.
- Willingness and ability to participate in Phase II of the study.
- Must be able to provide written informed consent.
- Phase II:
- Less than 1% CD36 present on platelets, compared with controls.
Who cannot join
- Phase I:
- A history of anemia or thrombocytopenia.
- Unwillingness or inability to participate in Phase II of the study.
- Phase II:
- Discovery of anemia (hemoglobin less than 11.1 g/dL for women, less than 12.7 for men) or thrombocytopenia (less than 162,000/microliter for women, less than 154,000/microliter for men) in the blood counts performed during Phase I.
- Subjects will not be excluded because of any medications.
Trial locations and contacts
1 site in 1 country.
United States1 site
Warren G. Magnuson Clinical Center (CC)
Bethesda, Maryland, 20892
About this study
Official title: Identification of Donors of CD36-Deficient Platelets Among Individuals on the NIH Campus
Plasma histidine-rich glycoprotein (HRG) binds to platelets in the presence of zinc (1). This binding is totally blocked by a monoclonal antibody directed against platelet membrane CD36. Therefore, CD36 is assumed to carry the platelet binding site for HRG (2). Because CD36 also has a variety of other ligands, including polyanionic lipids, it is also possible that it contains the binding site for heparin (also polyanionic) and might be involve in the pathogenesis of heparin-induced thrombocytopenia. Demonstrating absent HRG or heparin binding to platelets lacking CD36 would confirm that the binding sites for either or both of these ligands are located on this membrane protein. Because 3% to 11% of healthy Japanese are reported to lack CD36 on their platelets, this population is a practical source of cells for examining the physiologic role(s) for CD36. Therefore, we will recruit blood donors from the Japanese community on the NIH campus. Their platelets will tested for the presence of CD36. Recruitment will be closed after two individuals have been identified whose platelets lack CD36 and who are willing to donate 30 cc of blood on 4 or 5 subsequent occasions for binding studies with radiolabeled HRG and heparin.
Read the detailed description
Plasma histidine-rich glycoprotein (HRG) binds to platelets in the presence of zinc (1). This binding is totally blocked by a monoclonal antibody directed against platelet membrane CD36. Therefore, CD36 is assumed to carry the platelet binding site for HRG (2). Because CD36 also has a variety of other ligands, including polyanionic lipids, it is also possible that it contains the binding site for heparin (also polyanionic) and might be involved in the pathogenesis of heparin-induced thrombocytopenia. Demonstrating absent HRG or heparin binding to platelets lacking CD36 would confirm that the binding sites for either or both of these ligands are located on this membrane protein. Because 3% to 11% of healthy Japanese are reported to lack CD36 on their platelets, this population is a practical source of cells for examining the physiologic role(s) for CD36. It has also been reported that 2.4% of African Americans and 4% of Taiwanese lack this protein on their platelets. Therefore, we will recruit blood donors from the Japanese, African American, and Taiwanese community on the NIH campus. Their platelets will be tested for the presence of CD36. Recruitment will be closed after two individuals have been identified whose platelets lack CD36 and who are willing to donate 30 cc of blood on 4 or 5 subsequent occasions for binding studies with radiolabeled HRG and heparin.
- Conditions
- Thrombocytopenia
- Keywords
- Blood Donors, Employees, Heparin, Histidine-Rich Glycoprotein, Membrane, Healthy Volunteer
- Medical subject headings
- Thrombocytopenia
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Apr 2001 (estimated)
- Study startApr 2001
- Study completionFeb 2004
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for ThrombocytopeniaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Enrolment
- 150 participants
Sponsor and investigators
- Lead sponsor
- National Institutes of Health Clinical Center (CC)
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00015639
- Sponsor's protocol ID
- 010156
- Other IDs
- 01-CC-0156
- Status last verified
- Feb 2004
- First submitted
- 25 Apr 2001
- Last updated
- 4 Mar 2008
- Results posted
- No
Publications
Greenwalt DE, Lipsky RH, Ockenhouse CF, Ikeda H, Tandon NN, Jamieson GA. Membrane glycoprotein CD36: a review of its roles in adherence, signal transduction, and transfusion medicine. Blood. 1992 Sep 1;80(5):1105-15. No abstract available.
PubMed 1381234Rigotti A, Acton SL, Krieger M. The class B scavenger receptors SR-BI and CD36 are receptors for anionic phospholipids. J Biol Chem. 1995 Jul 7;270(27):16221-4. doi: 10.1074/jbc.270.27.16221.
PubMed 7541795Horne MK 3rd. Heparin binding to normal and abnormal platelets. Thromb Res. 1988 Jul 15;51(2):135-44. doi: 10.1016/0049-3848(88)90057-6.
PubMed 3187955
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Identification of Donors of CD36-Deficient Platelets Among Individuals on the NIH Campus
- ClinicalTrials.gov ID
- NCT00015639
- Acronym / sponsor ID
- 010156
- Conditions
- Thrombocytopenia
- Keywords
- Blood Donors, Employees, Heparin, Histidine-Rich Glycoprotein, Membrane, Healthy Volunteer
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 150 participants
- Lead sponsor
- National Institutes of Health Clinical Center (CC)US National Institutes of Health
- Study start
- Apr 2001
- Study completion
- Feb 2004
- First posted
- 26 Apr 2001 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Plasma histidine-rich glycoprotein (HRG) binds to platelets in the presence of zinc (1). This binding is totally blocked by a monoclonal antibody directed against platelet membrane CD36. Therefore, CD36 is assumed to carry the platelet binding site for HRG (2). Because CD36 also has a variety of other ligands, including polyanionic lipids, it is also possible that it contains the binding site for heparin (also polyanionic) and might be involve in the pathogenesis of heparin-induced thrombocytopenia. Demonstrating absent HRG or heparin binding to platelets lacking CD36 would confirm that the binding sites for either or both of these ligands are located on this membrane protein. Because 3% to 11% of healthy Japanese are reported to lack CD36 on their platelets, this population is a practical source of cells for examining the physiologic role(s) for CD36. Therefore, we will recruit blood donors from the Japanese community on the NIH campus. Their platelets will tested for the presence of CD36. Recruitment will be closed after two individuals have been identified whose platelets lack CD36 and who are willing to donate 30 cc of blood on 4 or 5 subsequent occasions for binding studies with radiolabeled HRG and heparin.
Detailed description
Plasma histidine-rich glycoprotein (HRG) binds to platelets in the presence of zinc (1). This binding is totally blocked by a monoclonal antibody directed against platelet membrane CD36. Therefore, CD36 is assumed to carry the platelet binding site for HRG (2). Because CD36 also has a variety of other ligands, including polyanionic lipids, it is also possible that it contains the binding site for heparin (also polyanionic) and might be involved in the pathogenesis of heparin-induced thrombocytopenia. Demonstrating absent HRG or heparin binding to platelets lacking CD36 would confirm that the binding sites for either or both of these ligands are located on this membrane protein. Because 3% to 11% of healthy Japanese are reported to lack CD36 on their platelets, this population is a practical source of cells for examining the physiologic role(s) for CD36. It has also been reported that 2.4% of African Americans and 4% of Taiwanese lack this protein on their platelets. Therefore, we will recruit blood donors from the Japanese, African American, and Taiwanese community on the NIH campus. Their platelets will be tested for the presence of CD36. Recruitment will be closed after two individuals have been identified whose platelets lack CD36 and who are willing to donate 30 cc of blood on 4 or 5 subsequent occasions for binding studies with radiolabeled HRG and heparin.
Study design
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (7 listed)
- Full Japanese, African American, and Taiwanese ancestry
- At least 18 years of age.
- Willingness and ability to participate in Phase II of the study.
- Must be able to provide written informed consent.
- Less than 1% CD36 present on platelets, compared with controls.
Key exclusion criteria (6 listed)
- A history of anemia or thrombocytopenia.
- Unwillingness or inability to participate in Phase II of the study.
- Discovery of anemia (hemoglobin less than 11.1 g/dL for women, less than 12.7 for men) or thrombocytopenia (less than 162,000/microliter for women, less than 154,000/microliter for men) in the blood counts performed during Phase I.
- Subjects will not be excluded because of any medications.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Mar 2008.
- Background: PubMed 1381234Greenwalt DE, Lipsky RH, Ockenhouse CF, Ikeda H, Tandon NN, Jamieson GA. Membrane glycoprotein CD36: a review of its roles in adherence, signal transduction, and transfusion medicine. Blood. 1992 Sep 1;80(5):1105-15. No abstract available.
- Background: PubMed 7541795Rigotti A, Acton SL, Krieger M. The class B scavenger receptors SR-BI and CD36 are receptors for anionic phospholipids. J Biol Chem. 1995 Jul 7;270(27):16221-4. doi: 10.1074/jbc.270.27.16221.
- Background: PubMed 3187955Horne MK 3rd. Heparin binding to normal and abnormal platelets. Thromb Res. 1988 Jul 15;51(2):135-44. doi: 10.1016/0049-3848(88)90057-6.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Thrombocytopenia, run by National Institutes of Health Clinical Center (CC) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Mar 2008. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00015639, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Mar 2008.