HLA-DPB1 and acute graft versus host disease: To explore the heterogeneity of HLA-DPB1 mismatches for acute GVHD (II-IV), we excluded 2 studies with small sample size and 1 study with GVH direction mismatches, and then pooled the remaining results, with hazard ratio of 1.34 (95% CI, 1.27 to 1.42; P < .001; I2 = 0.0%), which was consistent with it from the primary analysis.