Colloidal gold immunostaining for the detection of platelet reactive allo- and autoantibodies. Use on fresh and frozen cells.

ABSTRACT

BACKGROUND: Fresh washed platelets are commonly used as target cells for the detection of platelet reactive antibodies. The use of stored platelets would allow a faster execution of the tests and a rapid selection of phenotyped cells. METHODS: Glass-adherent platelet monolayers were freeze stored. The antigen-antibody reaction between platelet antigens and platelet reactive allo- or autoantibodies was revealed by a modified antiglobulin test, using colloidal gold-labeled anti-human IgG. Immunogold staining (IGS) was compared with the platelet suspension immunofluorescence test (PSIFT) and with the solid-phase red cell adherence assay (SPRCA). The reactivity of fresh and freeze-stored platelets was compared. RESULTS: IGS proved to be slightly less sensitive (10%) than PSIFT and SPRCA The results obtained with fresh and freeze-stored cells were scored identically. CONCLUSIONS: The immunogold staining assay on freeze-stored platelets seems to be a convenient technical approach for platelet serology.