This trial is active, not recruiting.

Conditions thrombocytopenia, platelet transfusion refractoriness
Sponsor National Institutes of Health Clinical Center (CC)
Start date July 2016
End date December 2017
Trial size 68 participants
Trial identifier NCT02858323, 16-CC-N155, 999916155



Platelets are blood cells that help blood clot. Some people have what is called thrombocytopenia. This means they have a low blood platelet count. They need platelet transfusions very often. Human leukocyte antigen (HLA) alloimmunization occurs for a lot of these people. They become refractory. This means their platelet levels no longer increase after transfusions. Researchers want to study a procedure that detects HLA antibodies. They want to test how well it predicts how a person will respond to a transfusion. They want to see if it does this better than the procedure that is usually used.


To study the effect of C1q-binding of Class I HLA antibodies on platelet refractoriness in people who get platelet transfusions. To test if this method better predicts response to platelet transfusion than the IgG solid phase immunoassay method.


People enrolled on protocols 11-C-0136, 08-H-0156, 03-C-0277, 01-C-0157, or 01-C-0129 who:

Agreed to have their specimens and data used for future research

Had Class I HLA antibodies detected by the IgG method

Had one or more platelet transfusions at NIH after the first positive HLA IgG antibody result


For each participant, researchers will look at a small portion of their archived plasma sample. The samples were left over from prior HLA antibody tests.

Participants samples will be analyzed. They will be tested to see if C1q-binding HLA antibodies are present. This will be done by solid phase immunoassay. Results will be compared with the past results of the IgG method.

Participants data will be stored in database that s protected by password.

United States No locations recruiting
Other countries No locations recruiting

Study Design

Observational model cohort
Time perspective retrospective

Primary Outcomes

Corrected count increment after platelet transfusion
time frame: 5 months

Eligibility Criteria

All participants from 3 years up to 80 years old.

- INCLUSION CRITERIA: 1. Class I HLA antibodies detected by the IgG solid phase immunoassay method 2. > 1 episode of platelet transfusion at NIH after the first positive HLA IgG antibody result EXCLUSION CRITERIA: 1) Hyperproliferative thrombocytopenia

Additional Information

Official title Complement (C1q) Binding to HLA Antibodies in a Solid-Phase Immunoassay and Clinical Effect on Platelet Transfusion
Principal investigator Willy A Flegel, M.D.
Description Human leukocyte antigen (HLA) alloimmunization is common in patients undergoing frequent platelet transfusion, and is the most important cause of immune platelet refractoriness. Management strategies in HLA alloimmune platelet-refractory patients include transfusion with HLA-matched or crossmatched platelets; however, in broadly-sensitized patients, or in patients with uncommon HLA types, antigen-negative or epitope compatible donors may be difficult to find. The Luminex immunoglobulin (Ig)G single-antigen-bead (SAB) solid phase immunoassay is now commonly used to detect HLA antibodies. However, an assay that specifically detects C1qbinding to HLA antibodies has been reported to identify a clinically relevant subset of HLA antibodies in solid organ transplantation; one group has studied the utility of this assay in platelet transfusion of HLA-alloimmunized platelet refractory patients. We intend to evaluate the ability of this C1-binding immunoassay to predict response to platelet transfusion in HLA alloimmune patients.
Trial information was received from ClinicalTrials.gov and was last updated in April 2017.
Information provided to ClinicalTrials.gov by National Institutes of Health Clinical Center (CC).