Flow cytometric analysis of 68 monoclonal anti-D reagents

68 monoclonal IgG anti-D were assessed for quantitative and qualitative binding to D variant red cells using a flow cytometric indirect immunofluorescence test. One antibody failed to bind to normal RhD pos. cells, but reacted weakly with D cat VI and D Cat VII cells. Quantitatively, binding varied approximately twenty-fold between different MAbs and different D variants. D cat III cells gave the lowest level of binding when compared with the D pos. controls. Qualitatively, R1VIr, R2VIr, R1VIIr and DFR samples failed to react with various MAbs regardless of the levels of binding of these MAbs to the D pos. controls, thus supporting the idea of missing epitopes in such variants.