CCR5 blockade decreases plasma levels of the gut GVHD biomarker Reg3a. (A-C) Serum concentrations of Reg3a (A), ST2 (B), or TNF-RI (C) from control (CON) and maraviroc-treated (MVC) patients at day 30 posttransplant. (D) Reg3a levels from control and maraviroc-treated patients at day 14 posttransplant. (E-F) Serum concentrations of Reg3a (E) or ST2 (F) from maraviroc-treated patients at the indicated time points. (G-I) Day 30 serum concentrations of Reg3a (G), ST2 (H), or TNF-RI (I) from maraviroc-treated patients who developed or did not develop grade 2-4 GVHD by day 180. Mean ± standard error (SE); *P < .05, Student t test for panels A-D and G-I; Mann-Whitney U test for panels E-F. ns, not significant.