There were no statistically significant differences in mean values of alanine transaminase (two-tailed T-test: p= 0.60), aspartate transaminase (two-tailed T-test: p= 0.88), and thrombocytes (two-tailed T-test: p= 0.95) in GvHD patients before ECP onset and after last ECP. Similarly, there were no statistically significant differences in median values of g-GT (Wilcoxon signed rank test: p=0.44, z=-.771). The gene discussed is GPT; the disease is graft versus host disease.