Cumulative incidence of GVHD after URD-PBSC transplantation by quartile (Q) of CD34⁺ dose. Higher CD34⁺ cell doses did not increase the incidence of GVHD. (A) Grades III-IV acute GVHD after MA transplantation (P = .599 at 180 days); (B) grades III-IV acute GVHD after RI/NMA transplantation (P = .305 at 180 days); (C) chronic GVHD after MA transplantation (P = .068 at 2 years); (D) chronic GVHD after RI/NMA transplantation (P = .189 at 2 years). MA: Q1 indicates no greater than 3.8; Q2, 3.8 to 6.2; Q3,6.2 to 9.5; Q4, greater than 9.5; RI/NMA: Q1, no greater than 3.6; Q, 3.6 to 5.9; Q3, 5.9 to 9.4; Q4, greater than 9.4 (× 10⁶ CD34⁺/kg).