PB smears of β-thalassemic/normal hematopoietic chimeras to demonstrate amplification of the genetically normal red cells.

(A) Wright-Giemsa–stained PB smear from an animal transplanted with genetically normal BM. (B) Smear from an animal transplanted with β-thalassemic BM. (C) Smear from a chimeric animal with 12% normal HSCs and 56% normal Hb in the PB. (D) Smear from a chimeric animal with 20% normal HSC engraftment and 81% normal Hb in the PB. Photomicrographs are at 250 × magnification.