Flow cytometric analysis of purified erythroid precursors from a patient with Cooley anemia.

(A) Reactivity with Hoechst 33342 on the abscissa and PI on the ordinate. The closeness of the contour lines reflects the numbers of cells reacting. There are 3 definable populations: PI reactive cells are dead; Hoechst 33342 are reactive, but PI nonreactive are apoptotic (shaded area); and the remaining cells (PI and Hoechst 33342 nonreactive) are alive and not apoptotic. Panel B is similar to A, except that FITC-AnV reactivity is recorded on the abscissa. The shaded area identifies the apoptotic population. (C) Reactivity of the erythroid precursors with FITC-AnV on the abscissa and Hoechst 33342 on the ordinate. The 2 methods identify the same apoptotic population (shaded area).