Combined pretreatment with KGF + PFT-β additively restores thymocyte cellularity after allogeneic BMT. Lethally irradiated B6 recipients of allogeneic (balb/c) BM were left untreated (BMT control) or pretreated with KGF, PFT-β, or KGF + PFT-β and analyzed for thymocyte cellularity at (A-E) 4 and (F-J) 8 weeks after BMT alongside age-/sex-matched, unmanipulated B6 controls (non-BMT control). Data shown are mean absolute numbers ± SEMs of total thymocytes. The data are pooled from 5 independent experiments with 4 to 5 mice per group; *P < .05 compared with BMT controls; #P < .05 compared with KGF- and PFT-β–treated BM transplant recipients.