Durchflusszytometrische Untersuchung zur Frage der Absorption und Elution von HLA-Klasse I-Antigenen auf Thrombozyten während der Lagerung als gepoolte Thrombozytenkonzentrate
Die Versorgung von HLA immunisierten Patienten mit geeigneten Thrombozyten stellt auch heute noch ein Problem in der Transfusionsmedizin dar. Zwar kann mittlerweile in den meisten Fällen durch die Bereitstellung passender Thrombozytapheresekonzentrate von HLA kompatiblen Einzelspendern ein adäquater...
|PDF Full Text
No Tags, Be the first to tag this record!
The origin of HLA class I molecules on platelets is still under discussion. Adsorption of HLA molecules on platelets using specific experimental conditions has been described. The study presented investigates whether there is a significant elution and adsorption of HLA class I molecules on platelets during storage of pooled random platelet concentrates (PRPC) under routine conditions. Platelet concentrates (PCs) from whole blood prepared from HLA-A2-positve and HLA-A2-negative donors, pooled and stored under routine conditions. In addition, platelets from HLA-A2-negative donors were pelleted and resuspended in cell-free plasma from HLA-A2-positiv donors. HLA-A2-positive PCs (positive control), HLA-A2-negative PCs (negative control) and HLA-A2-negative platelets in plasma from HLA-A2-negative donors were stored simultaneously. Binding of FITC-conjugated monoclonal murine antihuman Anti-HLA2 antibodies (anti-HLA-A2-mab) was measured during 5-day storage by flow cytometry. An increased binding of anti-HLA-A2-mab during storage was found on HLA-A2-negative platelets (p<0,005) independently whether they were incubated with cell-free plasma or platelets from HLA-A2-positve donors or autologous HLA-A-negative cell-free plasma. However, non-specific binding of IgG controls increased equally, whereas anti-HLA-A2-mab binding to platelets from HLA-A2-positive donors did not decrease during storage. The study suggests that there is no significant elution and adsorption of HLA class I antigens of platelets in pooled PCs during storage under the usual conditions for platelet storage. Increased anti-HLA-A2-mab signal was due to non-specific binding. Therefore, HLA class I compatible platelets should maintain their compatibility for an immunized patient when stored in a pool with HLA incompatible platelets and shortened survival after transfusion should not be expected.