Gross appearance of spleens obtained from mice 14 days after transplantation with 3 × 10⁴ purified bone marrow cells expressing the GATA-2irGFP (bottom row) or control irGFP vectors (top row). The mean splenic weight (mg) ± standard error for each group is indicated at right and were statistically significantly different (P < .04). The weight of the spleens from animals transplanted with GATA-2irGFP–expressing cells did not differ from the weight of spleens from animals that did not receive cells (148 ± 2; n = 2).