Identification of Donors of CD36-Deficient Platelets Among Japanese Individuals on the NIH Campus
Completed
Conditions studied: Thrombocytopenia
In brief
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.
Key facts
- Study ID
- NCT00015639
- Run by
- National Institutes of Health Clinical Center (CC)
- People needed
- 150
- Starts
- 2001-04-01
- Expected to finish
- 2004-02-01
- Last updated by the study team
- 2008-03-04
Who can join
Age: any. Sex: any. Healthy volunteers: not accepted.
You may qualify if…
- 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.
You may not qualify if…
- 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.
Where it is running
- Warren G. Magnuson Clinical Center (CC) — Bethesda, Maryland, United States
Full record on ClinicalTrials.gov
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