Erythroblastic islands from ICAM-4 null and wild-type mouse bone marrow. (A) Islands reconstituted from B6,129 ICAM-4 null and wild-type mouse bone marrow cells. Histogram of number of erythroblastic islands formed from 1 × 10⁵ single cells obtained from wild-type (n = 10) and ICAM-4 null (n = 10). *P < .001 when compared to islands formed from wild-type marrow. (B) Erythroblastic islands formed in vivo in ICAM-4 null and wild-type mice. Histogram of number of erythroblastic islands obtained from wild type (n = 6) and ICAM-4 null (n = 6). *P < .001 when compared to islands formed from wild-type marrow. Results are shown as mean ± SD.