Early inhibition of Th17 cells with neutralizing anti–IL-17 antibody delays the induction of BM failure in mice. Anti–IL-17 was administered at 100 μg intraperitoneally on alternating days (4 total injections) to the BM failure induction mouse model. Early anti–IL-17 neutralization consisted of 100 μg intraperitoneal injections on alternating days from 3 days before the LN injection to 3 days after (n = 5). Controls consisted of LN-injected mice (n = 3) and mice only irradiated (n = 2). Late anti–IL-17 neutralization consisted of 100 μg intraperitoneal injections on alternating days from 7 to 13 days after LN injections (n = 5). Controls consisted of LN-injected mice (n = 3) and mice only irradiated (n = 2). CBCs were performed using a Hemavet analyzer. Sternebrae were sectioned, hematoxylin and eosin–stained, and photographed. Experiments are represented as mean ± SD. P <.05 is considered statistically significant. (A) Schema of the anti–IL-17 neutralization experiment. (B) CBCs and total BM cells in TBI-only, B6 LN, and in B6 LN with anti–IL-17 antibody mice after early or late neutralization. (C) Representative hematoxylin and eosin sternebrae section (original magnification ×4) in TBI-only, B6 LN, and B6 LN with anti–IL-17 antibody after early (top panels) or late (bottom panels) neutralization.