Severe GI GvHD in both the lower and the upper GI tract also correlated with higher serum concentrations of Reg3α (161.5 ng/ml, 8.5–1744.0 ng/ml) as compared to mild GI GvHD (63.2 ng/ml, 4.5–2296 ng/ml, p = 0.002). This evidence concerns the gene REG3A and graft versus host disease.