Impaired homing and adhesion of FA-A hematopoietic cells. (A) A total of 6 to 10 × 10⁶ low-density BM mononuclear cells from healthy donors and patients with FA-A were injected into each sublethally irradiated NOD/SCID recipient. At 16 hours after the graft, donor-derived cells were isolated from each recipient mouse and colony (CFC) assays were performed to evaluate homing capacity of human hematopoietic progenitor cells. BM homing of human GM-CFCs was expressed as a percentage of the number of GM-CFCs infused. Results represent means plus or minus SD of 2 experiments (3 pairs of samples for each experiment and 4 recipient mice for each sample). *Difference between the FA-A and normal donors is significant at P < .05. (B) A total of 6 to 10 × 10⁶ low-density BM mononuclear cells from each healthy donor (n = 8) and patient with FA-A (n = 8) were injected into each sublethally irradiated NOD/SCID mouse. At 16 hours after the graft, BM nucleated cells were isolated from each recipient mouse and labeled with anti human CD45-APC and CD34-PE as well as 7-AAD, followed by flow cytometry to evaluate the proportion of donor-derived human progenitor cells in the bone marrow. BM homing of human CD34⁺ progenitors was expressed as a percentage of the number of CD34⁺ BM cells infused. The horizontal bar represents the median. *Difference between the patients with FA-A and the healthy donors is significant at P < .05. (C) Cell-matrix adhesion: 10⁵ low-density BM mononuclear cells isolated from each healthy donor and patient with FA-A were seeded into a 96-well plate coated with 20 μg/mL fibronectin CH-296. After a 2-hour incubation at 37°C, nonadherent cells were removed and adherent cells were detached and quantified. Data represent the mean plus or minus SD percentage of adhesion of 3 independent experiments in triplicates with samples from 3 healthy donors and 3 patients with FA-A. * Significance between the FA-A and normal cells at *P < .05. (D) Cell-cell adhesion: 5 × 10⁵ BM mononuclear cells from each healthy donor and patient with FA-A were added onto confluent normal BM-derived stromal monolayers and incubated for 4 hours at 37°C; the adherent cells were then subjected to CFC assay (2 pairs of healthy donors and patients with FA-A). Numbers are given as the percentage of input CFCs (mean ± SD) with 2 independent experiments in duplicates in each experiment. **P < .01. (E) Western analysis of FANCA expression in transduced normal and FA-A lymphoblasts using an anti-FANCA antibody. (F) FA-A lymphoblasts were transduced with retrovirus expression eGFP-FANCA or eGFP alone. After fluorescence-activated cell sorting (FACS) sorting, 5 × 10⁵ GFP⁺ cells together with untransduced normal and FA-A lymphoblasts were added into the 24-well plates coated with 20 μg/mL fibronectin and cultured for 2 hours. The nonadherent cells were removed, and adherent cells were detached and quantified. Shown is the mean plus or minus SD percentage of adhesion in 3 independent experiments. Fibronectin-mediated adhesion was significantly reduced in FA-A or eGFP (vector)–transduced FA-A cells compared with FANCA-complemented cells (**P < .01).