Human platelet antigen (HPA)-specific immunoglobulin M antibodies in neonatal alloimmune thrombocytopenia can inhibit the binding of HPA-specific immunoglobulin G antibodies
| Autor: | Matthew Hopkins, Krishna Kotecha, Anthony Calvert, Frances Green, Nina Bendukidze, Geoff Lucas, Anthony Poles |
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| Rok vydání: | 2017 |
| Předmět: |
biology
business.industry medicine.drug_class Immunology Hematology 030204 cardiovascular system & hematology medicine.disease Monoclonal antibody Molecular biology Immunoglobulin G Human platelet antigen Serology Isoantibodies 03 medical and health sciences 0302 clinical medicine Immunoglobulin M Neonatal alloimmune thrombocytopenia biology.protein Immunology and Allergy Medicine Antibody business 030215 immunology |
| Zdroj: | Transfusion. 57:1267-1271 |
| ISSN: | 0041-1132 |
| DOI: | 10.1111/trf.14047 |
| Popis: | BACKGROUND A term baby with unexplained thrombocytopenia and a platelet (PLT) count of 14 × 109/L (maternal PLT count was 200 × 109/L) was investigated for neonatal alloimmune thrombocytopenia. STUDY DESIGN AND METHODS Serologic investigations were performed using the PLT immunofluorescence test (PIFT), monoclonal antibody immobilization of PLT antigens (MAIPA), and a bead-based assay (BBA) with maternal sera taken up to 56 days postdelivery. One serum sample was also separated into “immunoglobulin (Ig)M-rich” and “IgM-depleted” fractions and tested for PLT-specific antibodies. The family was genotyped for HPA. RESULTS HPA-3a–specific IgM antibodies were detected in the PIFT and confirmed in the BBA. PLT-specific IgG HPA-3a antibodies were not detected in the MAIPA assay and BBA in the initial sample but were detected in both techniques in subsequent serum samples. Testing of IgM-rich and IgM-depleted fractions in the MAIPA assay revealed that IgG antibody binding of the IgM-depleted fraction was inhibited by approximately 50% when it was reconstituted with the IgM-rich fraction suggesting that the IgM antibodies blocked the binding of the IgG antibodies. This effect was not observed when the IgM-depleted fraction or untreated serum was diluted with elution buffer. Incompatibility for HPA-3 was identified between the mother and the infant. The infant received one HPA-1a, −5b negative neonatal PLT transfusion, and one random PLT transfusion, with satisfactory outcomes. Both units were later found to be HPA-3b3b. CONCLUSION HPA-3a IgM antibodies can inhibit PLT-specific HPA-3a IgG antibodies in the MAIPA assay. |
| Databáze: | OpenAIRE |
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