Post-HCT rATG exposure <30 AU × day/mL was associated with lower NRM, faster CD4⁺ IR, and lower overall all-cause mortality and thus higher OS. The correlation between post-HCT rATG exposure and NRM (A) and CD4⁺ IR (B). CD4 ⁺ IR was defined as CD4⁺ levels twice above 50 cells per µL at 2 consecutive measures within 100 days. (C) The correlation between post-HCT rATG exposure and all-cause mortality and OS.