Rat anti-mouse IL-17A (Clone #50104, catalog #MAB421) or IgG2A isotype control (Clone #54447, catalog #MAB006) antibody (R&D Systems, Inc., Minneapolis, MN) was administered weekly via intra-peritoneal injections (200μg/mouse, resuspended in 500μl sterile phosphate buffered saline [PBS]) starting 2 weeks post-HCT.19 (link)–21 (link) Based on pilot studies (data not shown), earlier and higher doses of anti-IL-17A were avoided due to concerns over potential impairment in hematopoietic cell engraftment.