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Human platelet activating antibodies.
1Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455.
Seminars in Thrombosis and Hemostasis
|January 1, 1992
Summary
Platelet antibodies can activate or inhibit platelet function, potentially explaining thrombotic and hemorrhagic symptoms in transfused patients. This study investigated HLA and platelet-specific antibodies, revealing diverse effects on platelet activation and aggregation.
Area of Science:
- Immunology
- Hematology
- Transfusion Medicine
Background:
- Platelet antibodies are implicated in transfusion reactions.
- Neonatal alloimmune thrombocytopenia (NAIT) and reactions in multiply transfused patients involve platelet antibodies.
- Human Leukocyte Antigen (HLA) antibodies and platelet-specific antibodies can be present in these patient populations.
Observation:
- Multispecific HLA antibodies and platelet-specific antibodies (anti-HPA-1a, anti-HPA-3a, anti-HPA-1b) were identified.
- HLA antibodies induced potent platelet aggregation and ATP release.
- Anti-HPA-1b antibodies caused agglutination but not ATP release, yet blocked subsequent ADP stimulation.
Findings:
- HLA antibodies strongly activated platelets, causing aggregation and dense granule ATP release.
- Platelet-specific anti-HPA-1b antibodies induced agglutination and inhibited subsequent platelet activation by ADP, epinephrine, and thrombin.
- These antibodies demonstrated varied effects, including potent activation by HLA antibodies and inhibitory effects by anti-HPA-1b, impacting thrombin-induced activation.
Implications:
- Transfused platelets can be either activated or inhibited by various platelet antibodies.
- Platelet-reactive antibodies in multiply transfused patients may contribute to observed thrombotic and hemorrhagic complications.
- Understanding these antibody-mediated effects is crucial for managing transfusion-related complications.