KGF increases thymic cellularity and numbers of peripheral T cells on day 19 after allogeneic BMT. Eight- to 10-week-old B6 mice were lethally irradiated (11 Gy) and transplanted with T cell–depleted LP BM (5 × 10⁶). Some recipients received KGF (5 mg/kg/day) or PBS subcutaneously pretransplant on days −6 to −4. On day 19, thymic cellularity (A, *P = .002), CD4⁺ and CD8⁺ populations from spleens (B, *P = .02, and C, *P = .003), and inguinal LN (D, *P = .02, and E, *P = .02) were determined by flow cytometry. Values from individual mice are shown with medians. Data are pooled from 2 experiments with similar results.