[Expression of RhD antigen on RBC of different RhD serotype by flow cytometry]

This study was purposed to establish the method of quantifying RhD antigen on red blood cells (RBC) by flow cytometry (FCM) and to explore the expression of D antigen on RBC of different RhD serotype. RhD(+) RBCs and RhD(-) RBCs were mixed in 1:1 ratio. Cells were stained by the indirect method (IgG anti-D as the first antibody, FITC-anti-IgG F(ab')2 as the second antibody), and the ratio of RhD(+) on RBCs was quantified by FCM. The optimal dosage of IgG anti-D was defined. Expression of RhD antigen on RBC of RhD(+), weak D, RhDel and RhD(-) type were detected by FCM. The results showed that optimal dilution of IgG anti-D monoclonal antibody was 1:4, 1x10(6) cells/50 microl. The percentage of D(+) RBC of RhD(+), weak D, RhDel and RhD(-) type were 96.8+/-2.97%, 79.5+/-9.88%, 47.8+/-11.43%, 3.7+/-2.96%, respectively. The mean fluorescence intensity (MFI) of RhD antigen expression of RhD(+), weak D, RhDel and RhD(-) type were 33.3+/-6.21 Dal, 18.6+/-5.39 Dal, 7.10+/-1.17 Dal, 0.79+/-0.55 Dal, respectively. In conclusion, there are significant differences of RhD antigen expressions among RBC of different RhD serotypes. The level of antigen on RhD(+) RBC is the highest and then weak D the next, while the level of antigen on RhDel RBC is the lowest level.