Relationship between α₂ genotype and platelet α₂β₁ density.

The level of platelet α₂β₁ was determined in freshly drawn whole blood by flow cytometry using murine monoclonal anti-α₂β₁ (8C12). Mean fluorescence intensity (MFI) is plotted on the ordinate. All donors expressed only alleles A1 or A2 and are subdivided with respect to expression of these alleles: left panel, homozygous A2/A2; center panel, heterozygous A1/A2; and right panel, homozygous A1/A1. As indicated on the abscissa, donors are further subdivided with respect to number of haplotypes expressing the −52T sequence (2, 1, or 0). Boxes represent the mean (center horizontal bar) ± 1 SD for each data set.