The increasing use of platelet transfusion in the treatment of thrombocytopenia has
stimulated significant advances in the understanding of platelet immunology.
A number of antigens which are also shared by granulocytes and Iymphocytes have
been found on platelets. These have been shown more recently to be histocompatibility
antigens, which are clinically important in causing neonatal and posttransfusion
thrombocytopenia and in decreasing the platelet survival of transfused platelets in
individuals receiving multiple transfusions.
In recent years, many attempts have been made to replace the cumbersome and
insensitive complement fixation test with more sensitive methods. These tests have
included inhibition of serotonine uptake, release of 51Cr from platelets and
assay of platelet factor 3.
In this study, the simplified platelet factor 3 assay (Hirschman & Gralnick, 1974) was
evaluated in 50 sera from thrombocytopenia with various clinical disorders and in 20
sera from the pregnant women.
The results are as follows;
1. About 40% of patients with thrombocytopenia had the malignant tumors and leukemia.
Other clinical disorders with thrombocytopenia include hepatic disease, idiopathic throm
tobcytopenic purpura, disseminated intravascular congulation, salmonellosis, aplastic
anemia and etc.
2. Detection of platelet antibody by PF 3 assay were significantly frequent in the
patients with past history of transfusions.
3. By PF 3 assay, platelet antibodies are detectable in 9 cases among 20 pregnant
women and the positive frequency was increased with the number of pregnancy.
4. By PF 3 assay, platelet antibody was detectable in 3 out of 4 cases of idiopathic
thrombocytopenic purpura.
5. The platelet factor 3 assay appear to be sensitive and applicable in most clinical
laboratories.
6. The PF 3 assay may be used as a pretransfusion compatibility test for the patients
refractory to platelet transfusions.
7. Studies on the false positive reactions and reproducibility need to be further
investigated.
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