Darc expression on erythrocytes. (A) A representative field showing Darc expression on erythrocytes visualized by confocal microscopy (“Darc expression”). (B) Flow cytometric histograms of red cell Darc expression from representative persons with A/A (blue) and G/G (red) genotypes. The corresponding isotype controls are shown as red and blue lines. The table indicates the average values for the percentage of erythrocytes expressing Darc and the mean fluorescent intensity from persons with G/G, A/G, and A/A genotypes, as described in “Darc expression.”