RNA analysis.

RT-PCR analysis was done to analyze CD34 expression in the marrow of long-term engrafted primary bnx recipients of human CD34⁺/CD38⁻ cells. The KG-1A cell line was used as a positive control, and nontransplanted bnx mouse marrow as a negative control. Marrow samples from 3 bnx mice that had no cell surface CD34 expression were tested. Eight months after engraftment, mouse 1 had 22.1% human CD45⁺ cells in its marrow. Twelve months after engraftment, mouse 2 had 13.4% human CD45⁺ cells in its marrow and mouse 3 had 35.6% human CD45⁺ cells in its marrow.