Thrombocyte counts after 5 Gy TBI (day 0) for monkeys treated with TPO (▪, n = 4), TPO/GM-CSF (┌, n = 4), or GM-CSF (□, n = 4) in the upper panel and TPO/G-CSF (┌, n = 4) or G-CSF (□, n = 3) in the lower panel. Data represent the arithmetic mean ± SD of the various treatment groups. The horizontal line defines the level of thrombocytopenia (40 × 10⁹/L) below which thrombocyte transfusions are given.